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  • Add objects to Arraylist inside loop and get a list of them outside loops

    - by AgusDG
    Im already done with a method to do a shot on a board (bidimensional array). THe shot goes from the bottom to the top, and depending of the direction, it do bounces on the walls to get to the top. The thing is that I did the method to represent the trayectory with an 'x'. Now, I want to add the coordinates x and y of each position of the shot (b [x][y]) to and Arraylist of Objects Position. public Position(int row,int col) { this.row = row; this.col = col; } The thing is that the method uses a for loop and inside if loops, and I'll need to create the objects inside, and get them outside. I did that : public static ArrayList<Position> showTrayectory (char [][] b , int shotDirection, char bubble){ int row = 0, col = 0; ArrayList<Position> aListPos = new ArrayList<Position>(); Position positionsOfShot = new Position(row,col); START = ((RIGHT_WALL)/2) + shotDirection; boolean shotRight = false; if(shotDirection < 0) shotRight = false; else if(shotDirection > 0) shotRight = true; for(int y = BOTTOM,x = START ;y >= 0;y--) { if(!isOut(y,x) && !emptyCell(y,x)) break; if(x <= LEFT_WALL) shotRight = true; if(x >= RIGHT_WALL) shotRight = false; if(!isOut(y,x) && shotRight == true) { positionsOfShot = new Position(y,x); aListPos.add(positionsOfShot); b[y][x] = SHOT; ++x; } if(!isOut(y,x) && shotRight == false){ positionsOfShot = new Position(y,x); aListPos.add(positionsOfShot); b[y][x] = SHOT; --x; } } // The nested for loops below are for showing the positions // But I dont need it that way // I must get the trayectory from an ArrayList and print it from there for(int y=0;y < b.length;y++){ System.out.println(); for(int x=0;x < b[y].length;x++){ System.out.print(" "+b [y][x]+" "); } } System.out.println("\nTrayectory of the shot ["+shotDirection+"]"); System.out.println("Next bubble ["+bubble+"]"); for( Position ii : aListPos){ System.out.println("(" + positionsOfShot.getFila() + "," + positionsOfShot.getColumna()+")"); } return aListPos; } The sentence " b[y][x] = SHOT; " is still there, to see the proper trayectory of the shot (its not needed that way), but what I need, is getting the trayectory in an ArrayList, and print the trayectory from there. All that I get is a wrong position, and repeated during the number of positions the shot goes through. I need some help. I suppose the problem is that Im creating and adding Position Objects inside an ArrayList inside loops, but in a wrong way. I will need you to explain me how to do it properly ; ) Thanks in advance. I'll add the output for you see better what is that above haha *************************** y b y b g r b g o y g a a r y o y y r b y g r r o b o y y g b a r y r o a y y o o r r g r - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - x - - - - - - - x - - - - - - - x - - - Trayectory of the shot [1] Next bubble [y] (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) Action?

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  • How to copy this portion of a text file out and put into a hash using rails? (VATsim datafile)

    - by Rusty Broderick
    Hi I'm trying to work out how i can cut out the section between !CLIENTS and the '; ;' and then to parse it into a hash in order to make an xml file. Honestly have no idea how to do it. The file is as follows: vatsim-data.txt original file here ; Created at 30/12/2010 01:29:14 UTC by Data Server V4.0 ; ; Data is the property of VATSIM.net and is not to be used for commercial purposes without the express written permission of the VATSIM.net Founders or their designated agent(s ). ; ; Sections are: ; !GENERAL contains general settings ; !CLIENTS contains informations about all connected clients ; !PREFILE contains informations about all prefiled flight plans ; !SERVERS contains a list of all FSD running servers to which clients can connect ; !VOICE SERVERS contains a list of all running voice servers that clients can use ; ; Data formats of various sections are: ; !GENERAL section - VERSION is this data format version ; RELOAD is time in minutes this file will be updated ; UPDATE is the last date and time this file has been updated. Format is yyyymmddhhnnss ; ATIS ALLOW MIN is time in minutes to wait before allowing manual Atis refresh by way of web page interface ; CONNECTED CLIENTS is the number of clients currently connected ; !CLIENTS section - callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: ; !PREFILE section - callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: ; !SERVERS section - ident:hostname_or_IP:location:name:clients_connection_allowed: ; !VOICE SERVERS section - hostname_or_IP:location:name:clients_connection_allowed:type_of_voice_server: ; ; Field separator is : character ; ; !GENERAL: VERSION = 8 RELOAD = 2 UPDATE = 20101230012914 ATIS ALLOW MIN = 5 CONNECTED CLIENTS = 515 ; ; !VOICE SERVERS: voice2.vacc-sag.org:Nurnberg:Europe-CW:1:R: voice.vatsim.fi:Finland - Sponsored by Verkkokauppa.com and NBL Solutions:Finland:1:R: rw.liveatc.net:USA, California:Liveatc:1:R: rw1.vatpac.org:Melbourne, Australia:Oceania:1:R: spain.vatsim.net:Spain:Vatsim Spain Server:1:R: voice.nyartcc.org:Sponsored by NY ARTCC:NY-ARTCC:1:R: voice.zhuartcc.net:Sponsored by Houston ARTCC:ZHU-ARTCC:1:R: ; ; !CLIENTS: 01PD:1090811:prentis gibbs KJFK:PILOT::40.64841:-73.81030:15:0::0::::USA-E:100:1:1200::::::::::::::::::::20101230010851:28:30.1:1019: 4X-BRH:1074589:george sandoval LLJR:PILOT::50.05618:-125.84429:10819:206:C337/G:150:CYAL:FL120:CCI9:EUROPE-C2:100:1:6043:::2:I:110:110:1:26:2:59:: /T/:DCT:0:0:0:0:::20101230005323:129:29.76:1007: 50125:1109107:Dave Frew KEDU:PILOT::46.52736:-121.95317:23877:471:B/B744/F:530:KTCM:30000:KLSV:USA-E:100:1:7723:::1:I:0:116:0:0:0:0:::GPS DIRECT.:0:0:0:0:::20101230012346:164:29.769:1008: 85013:1126003:Dmitry Abramov UWWW:PILOT::76.53819:71.54782:33444:423:T/ZZZZ/G:500:UUDD:FL330:ULAA:EUROPE-C2:100:1:2200:::2:I:0:2139:0:0:0:0:ULLI::BITSA DCT WM/N0485S1010 DCT KS DCT NE R22 ULWW B153 LAPEK B210 SU G476 OLATA:0:0:0:0:::20101229215815:62:53.264:1803: ; ; !SERVERS: EUROPE-C2:88.198.19.202:Europe:Center Europe Server Two:1: ; ; END I want to format the html with the tags with client being the parent and the nested tags as follows: callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: Any help in solving this would be much appreciated!

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  • IE6 rendering bug. Some parsed <li> elements are losing their closing tags.

    - by Jeff Fohl
    I have been working with IE6 for many years [sob], but have never seen this particular bug before, and I can't seem to find a reference to it on the Web. The problem appears to be with how IE6 is parsing the HTML of a nested list. Even though the markup is correct, IE6 somehow munges the code when it is parsed, and drops the closing tags of some of the <li> elements. For example, take the following code: <!DOCTYPE html> <head> <title>My Page</title> </head> <body> <div> <ul> <li><a href=''>Child A</a> <div> <ul> <li><a href=''>Grandchild A</a></li> </ul> </div> </li> <li><a href=''>The Child B Which Is Not A</a> <div> <ul> <li><a href=''>Grandchild B</a></li> <li><a href=''>Grandchild C</a></li> </ul> </div> </li> <li><a href=''>Deep Purple</a></li> <li><a href=''>Led Zeppelin</a></li> </ul> </div> </body> </html> Now take a look at how IE6 renders this code, after it has run it through the IE6 rendering engine: <HTML> <HEAD> <TITLE>My Page</TITLE></HEAD> <BODY> <DIV> <UL> <LI><A href="">Child A</A> <DIV> <UL> <LI><A href="">Grandchild A</A> </LI> </UL> </DIV> <LI><A href="">The Child B Which Is Not A</A> <DIV> <UL> <LI><A href="">Grandchild B</A> <LI><A href="">Grandchild C</A> </LI> </UL> </DIV> <LI><A href="">Deep Purple</A> <LI><A href="">Led Zeppelin</A> </LI> </UL> </DIV> </BODY> </HTML> Note how on some of the <li> elements there are no longer any closing tags, even though it existed in the source HTML. Does anyone have any idea what could be triggering this bug, and if it is possible to avoid it? It seems to be the source of some visual display problems in IE6. Many thanks for any advice.

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  • How do I use accepts_nested_attributes_for?

    - by Angela
    Editing my question for conciseness and to update what I've done: How do I model having multiple Addresses for a Company and assign a single Address to a Contact, and be able to assign them when creating or editing a Contact? I want to use nested attributes to be able to add an address at the time of creating a new contact. That address exists as its own model because I may want the option to drop-down from existing addresses rather than entering from scratch. I can't seem to get it to work. I get a undefined method `build' for nil:NilClass error Here is my model for Contacts: class Contact < ActiveRecord::Base attr_accessible :first_name, :last_name, :title, :phone, :fax, :email, :company, :date_entered, :campaign_id, :company_name, :address_id, :address_attributes belongs_to :company belongs_to :address accepts_nested_attributes_for :address end Here is my model for Address: class Address < ActiveRecord::Base attr_accessible :street1, :street2, :city, :state, :zip has_many :contacts end I would like, when creating an new contact, access all the Addresses that belong to the other Contacts that belong to the Company. So here is how I represent Company: class Company < ActiveRecord::Base attr_accessible :name, :phone, :addresses has_many :contacts has_many :addresses, :through => :contacts end Here is how I am trying to create a field in the View for _form for Contact so that, when someone creates a new Contact, they pass the address to the Address model and associate that address to the Contact: <% f.fields_for :address, @contact.address do |builder| %> <p> <%= builder.label :street1, "Street 1" %> </br> <%= builder.text_field :street1 %> <p> <% end %> When I try to Edit, the field for Street 1 is blank. And I don't know how to display the value from show.html.erb. At the bottom is my error console -- can't seem to create values in the address table: My Contacts controller is as follows: def new @contact = Contact.new @contact.address.build # Iundefined method `build' for nil:NilClass @contact.date_entered = Date.today @campaigns = Campaign.find(:all, :order => "name") if params[:campaign_id].blank? else @campaign = Campaign.find(params[:campaign_id]) @contact.campaign_id = @campaign.id end if params[:company_id].blank? else @company = Company.find(params[:company_id]) @contact.company_name = @company.name end end def create @contact = Contact.new(params[:contact]) if @contact.save flash[:notice] = "Successfully created contact." redirect_to @contact else render :action => 'new' end end def edit @contact = Contact.find(params[:id]) @campaigns = Campaign.find(:all, :order => "name") end Here is a snippet of my error console: I am POSTING the attribute, but it is not CREATING in the Address table.... Processing ContactsController#create (for 127.0.0.1 at 2010-05-12 21:16:17) [POST] Parameters: {"commit"="Submit", "authenticity_token"="d8/gx0zy0Vgg6ghfcbAYL0YtGjYIUC2b1aG+dDKjuSs=", "contact"={"company_name"="Allyforce", "title"="", "campaign_id"="2", "address_attributes"={"street1"="abc"}, "fax"="", "phone"="", "last_name"="", "date_entered"="2010-05-12", "email"="", "first_name"="abc"}} Company Load (0.0ms)[0m [0mSELECT * FROM "companies" WHERE ("companies"."name" = 'Allyforce') LIMIT 1[0m Address Create (16.0ms)[0m [0;1mINSERT INTO "addresses" ("city", "zip", "created_at", "street1", "updated_at", "street2", "state") VALUES(NULL, NULL, '2010-05-13 04:16:18', NULL, '2010-05-13 04:16:18', NULL, NULL)[0m Contact Create (0.0ms)[0m [0mINSERT INTO "contacts" ("company", "created_at", "title", "updated_at", "campaign_id", "address_id", "last_name", "phone", "fax", "company_id", "date_entered", "first_name", "email") VALUES(NULL, '2010-05-13 04:16:18', '', '2010-05-13 04:16:18', 2, 2, '', '', '', 5, '2010-05-12', 'abc', '')[0m

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  • Hibernate - H2 db -- Could not parse mapping document from resource

    - by user1849757
    * Each of below files are in same location * Error : SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". SLF4J: Defaulting to no-operation (NOP) logger implementation SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details. org.hibernate.InvalidMappingException: Could not parse mapping document from resource ./employee.hbm.xml at org.hibernate.cfg.Configuration.addResource(Configuration.java:616) at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1635) at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1603) at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1582) at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1556) at org.hibernate.cfg.Configuration.configure(Configuration.java:1476) at org.hibernate.cfg.Configuration.configure(Configuration.java:1462) at com.yahoo.hibernatelearning.FirstExample.main(FirstExample.java:19) Caused by: org.hibernate.InvalidMappingException: Could not parse mapping document from input stream at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:555) at org.hibernate.cfg.Configuration.addResource(Configuration.java:613) ... 7 more Caused by: org.dom4j.DocumentException: http://hibernate.sourceforge.net/%0Ahibernate-mapping-3.0.dtd Nested exception: http://hibernate.sourceforge.net/%0Ahibernate-mapping-3.0.dtd at org.dom4j.io.SAXReader.read(SAXReader.java:484) at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:546) ... 8 more Exception in thread "main" java.lang.NullPointerException at com.yahoo.hibernatelearning.FirstExample.main(FirstExample.java:33) Hibernate Config: hibernate.cfg.xml <?xml version='1.0' encoding='utf-8'?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.connection.driver_class">org.h2.Driver</property> <property name="hibernate.connection.url">jdbc:h2:./db/repository</property> <property name="hibernate.connection.username">sa</property> <property name="hibernate.connection.password"></property> <property name="hibernate.default_schema">PUBLIC</property> <property name="hibernate.dialect">org.hibernate.dialect.H2Dialect</property> <property name="hibernate.show_sql">true</property> <property name="hibernate.hbm2ddl.auto">update</property> <!-- Mapping files --> <mapping resource="./employee.hbm.xml"/> </session-factory> </hibernate-configuration> Mapping Config: employee.hbm.xml <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/ hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="com.yahoo.hibernatelearning.Employee" table="employee"> <id name="empId" type="int" column="emp_id" > <generator class="native"/> </id> <property name="empName"> <column name="emp_name" /> </property> <property name="empSal"> <column name="emp_sal" /> </property> </class> </hibernate-mapping>

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  • Java code optimization leads to numerical inaccuracies and errors

    - by rano
    I'm trying to implement a version of the Fuzzy C-Means algorithm in Java and I'm trying to do some optimization by computing just once everything that can be computed just once. This is an iterative algorithm and regarding the updating of a matrix, the clusters x pixels membership matrix U, this is the update rule I want to optimize: where the x are the element of a matrix X (pixels x features) and v belongs to the matrix V (clusters x features). And m is a parameter that ranges from 1.1 to infinity. The distance used is the euclidean norm. If I had to implement this formula in a banal way I'd do: for(int i = 0; i < X.length; i++) { int count = 0; for(int j = 0; j < V.length; j++) { double num = D[i][j]; double sumTerms = 0; for(int k = 0; k < V.length; k++) { double thisDistance = D[i][k]; sumTerms += Math.pow(num / thisDistance, (1.0 / (m - 1.0))); } U[i][j] = (float) (1f / sumTerms); } } In this way some optimization is already done, I precomputed all the possible squared distances between X and V and stored them in a matrix D but that is not enough, since I'm cycling througn the elements of V two times resulting in two nested loops. Looking at the formula the numerator of the fraction is independent of the sum so I can compute numerator and denominator independently and the denominator can be computed just once for each pixel. So I came to a solution like this: int nClusters = V.length; double exp = (1.0 / (m - 1.0)); for(int i = 0; i < X.length; i++) { int count = 0; for(int j = 0; j < nClusters; j++) { double distance = D[i][j]; double denominator = D[i][nClusters]; double numerator = Math.pow(distance, exp); U[i][j] = (float) (1f / (numerator * denominator)); } } Where I precomputed the denominator into an additional column of the matrix D while I was computing the distances: for (int i = 0; i < X.length; i++) { for (int j = 0; j < V.length; j++) { double sum = 0; for (int k = 0; k < nDims; k++) { final double d = X[i][k] - V[j][k]; sum += d * d; } D[i][j] = sum; D[i][B.length] += Math.pow(1 / D[i][j], exp); } } By doing so I encounter numerical differences between the 'banal' computation and the second one that leads to different numerical value in U (not in the first iterates but soon enough). I guess that the problem is that exponentiate very small numbers to high values (the elements of U can range from 0.0 to 1.0 and exp , for m = 1.1, is 10) leads to ver y small values, whereas by dividing the numerator and the denominator and THEN exponentiating the result seems to be better numerically. The problem is it involves much more operations. Am I doing something wrong? Is there a possible solution to get both the code optimized and numerically stable? Any suggestion or criticism will be appreciated.

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  • Please help fix and optimize this query

    - by user607217
    I am working on a system to find potential duplicates in our customers table (SQL 2005). I am using the built-in SOUNDEX value that our software computes when customers are added/updated, but I also implemented the double metaphone algorithm for better matching. This is the most-nested query I have created, and I can't help but think there is a better way to do it and I'd like to learn. In the inner-most query I am joining the customer table to the metaphone table I created, then finding customers that have identical pKey (primary phonetic key). I take that, union that with customers that have matching soundex values, and then proceed to score those matches with various text similarity functions. This is currently working, but I would also like to add a union of customers whose aKey (alternate phonetic key) match. This would be identical to "QUERY A" except to substitute on (c1Akey = c2Akey) for the join. However, when I attempt to include that, I get errors when I try to execute my query. Here is the code: --Create aggregate ranking select c1Name, c2Name, nDiff, c1Addr, c2Addr, aDiff, c1SSN, c2SSN, sDiff, c1DOB, c2DOB, dDiff, nDiff+aDiff+dDiff+sDiff as Score ,(sDiff+dDiff)*1.5 + (nDiff+dDiff)*1.5 + (nDiff+sDiff)*1.5 + aDiff *.5 + nDiff *.5 as [Rank] FROM ( --Create match scores for different fields SELECT c1Name, c2Name, c1Addr, c2Addr, c1SSN, c2SSN, c1LTD, c2LTD, c1DOB, c2DOB, dbo.Jaro(c1name, c2name) AS nDiff, dbo.JaroWinkler(c1addr, c2addr) AS aDiff, CASE WHEN c1dob = '1901-01-01' OR c2dob = '1901-01-01' OR c1dob = '1800-01-01' OR c2dob = '1800-01-01' THEN .5 ELSE dbo.SmithWaterman(c1dob, c2dob) END AS dDiff, CASE WHEN c1ssn = '000-00-0000' OR c2ssn = '000-00-0000' THEN .5 ELSE dbo.Jaro(c1ssn, c2ssn) END AS sDiff FROM -- Generate list of possible matches based on multiple phonetic matching fields ( select * from -- List of similar names from pKey field of ##Metaphone table --QUERY A BEGIN (select customers.custno as c1Custno, name as c1Name, haddr as c1Addr, ssn as c1SSN, lasttripdate as c1LTD, dob as c1DOB, soundex as c1Soundex, pkey as c1Pkey, akey as c1Akey from Customers WITH (nolock) join ##Metaphone on customers.custno = ##Metaphone.custno) as c1 JOIN (select customers.custno as c2Custno, name as c2Name, haddr as c2Addr, ssn as c2SSN, lasttripdate as c2LTD, dob as c2DOB, soundex as c2Soundex, pkey as c2Pkey, akey as c2Akey from Customers with (nolock) join ##Metaphone on customers.custno = ##Metaphone.custno) as c2 on (c1Pkey = c2Pkey) and (c1Custno < c2Custno) WHERE (c1Name <> 'PARENT, GUARDIAN') and c1soundex != c2soundex --QUERY A END union --List of similar names from pregenerated SOUNDEX field (select t1.custno, t1.name, t1.haddr, t1.ssn, t1.lasttripdate, t1.dob, t1.[soundex], 0, 0, t2.custno, t2.name, t2.haddr, t2.ssn, t2.lasttripdate, t2.dob, t2.[soundex], 0, 0 from Customers t1 WITH (nolock) join customers t2 with (nolock) on t1.[soundex] = t2.[soundex] and t1.custno < t2.custno where (t1.name <> 'PARENT, GUARDIAN')) ) as a ) as b where (sDiff+dDiff)*1.5 + (nDiff+dDiff)*1.5 + (nDiff+sDiff)*1.5 + aDiff *.5 + nDiff *.5 >= 7.5 order by [rank] desc, score desc Previously, I was using joins such as on c1.pkey = c2.pkey or c1.akey = c2.akey or c1.soundex = c2.soundex but the performance was horrendous, and using unions seems to be working a lot better. Out of 103K customers, tt is currently generating a list of 8.5M potential matches (based on the phonetic codes) in 2.25 minutes, and then taking another 2 to score, rank and filter those down to about 3000. So I am happy with the performance, I just can't help but think there is a better way to structure this, and I need help adding the extra union condition. Thanks!

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  • C# slowdown while creating a bitmap - calculating distances from a large List of places for each pixel

    - by user576849
    I'm creating a graphic of the glow of lights above a geographic location based upon Walkers Law: Skyglow=0.01*Population*DistanceFromCenter^-2.5 I have a CSV file of places with 66,000 records using 5 fields (id,name,population,latitude,longitude), parsed on the FormLoad event and stored it in: List<string[]> placeDataList Then I set up nested loops to fill in a bitmap using SetPixel. For each pixel on the bitmap, which represents a coordinate on a map (latitude and longitude), the program loops through placeDataList – calculating the distance from that coordinate (pixel) to each place record. The distance (along with population) is used in a calculation to find how much cumulative sky glow is contributed to the coordinate from each place record. So, for every pixel, 66,000 distance calculations must be made. The problem is, this is predictably EXTREMELY slow – on the order of one line of pixels per 30 seconds or so on a 320 pixel wide image. This is unrelated to SetPixel, which I know is also slow, because the speed is similarly slow when adding the distance calculation results to an array. I don’t actually need to test all 66,000 records for every pixel, only the records within 150 miles (i.e. no skyglow is contributed to a coordinate from a small town 3000 miles away). But to find which records are within 150 miles of my coordinate I would still need to loop through all the records for each pixel. I can't use a smaller number of records because all 66,000 places contribute to skyglow for SOME coordinate in my map as it loops. This seems like a Catch-22, so I know there must be a better method out there. Like I mentioned, the slowdown is related to how many calculations I’m making per pixel, not anything to do with the bitmap. Any suggestions? private void fillPixels(int width) { Color pixelColor; int pixel_w = width; int pixel_h = (int)Math.Floor((width * 0.424088664)); Bitmap bmp = new Bitmap(pixel_w, pixel_h); for (int i = 0; i < pixel_h; i++) for (int j = 0; j < pixel_w; j++) { pixelColor = getPixelColor(i, j); bmp.SetPixel(j, i, pixelColor); } bmp.Save("Nightfall", System.Drawing.Imaging.ImageFormat.Jpeg); pictureBox1.Image = bmp; MessageBox.Show("Done"); } private Color getPixelColor(int height, int width) { int c; double glow,d,cityLat,cityLon,cityPop; double testLat, testLon; int size_h = (int)Math.Floor((size_w * 0.424088664)); ; testLat = (height * (24.443136 / size_h)) + 24.548874; testLon = (width * (57.636853 / size_w)) -124.640767; glow = 0; for (int i = 0; i < placeDataList.Count; i++) { cityPop=Convert.ToDouble(placeDataList[i][2]); cityLat=Convert.ToDouble(placeDataList[i][3]); cityLon=Convert.ToDouble(placeDataList[i][4]); d = distance(testLat, testLon, cityLat, cityLon,"M"); if(d<150) glow = glow+(0.01 * cityPop * Math.Pow(d, -2.5)); } if (glow >= 1) glow=1; c = (int)Math.Ceiling(glow * 255); return Color.FromArgb(c, c, c); }

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  • Why is FubuMVC new()ing up my view model in PartialForEach?

    - by Jon M
    I'm getting started with FubuMVC and I have a simple Customer - Order relationship I'm trying to display using nested partials. My domain objects are as follows: public class Customer { private readonly IList<Order> orders = new List<Order>(); public string Name { get; set; } public IEnumerable<Order> Orders { get { return orders; } } public void AddOrder(Order order) { orders.Add(order); } } public class Order { public string Reference { get; set; } } I have the following controller classes: public class CustomersController { public IndexViewModel Index(IndexInputModel inputModel) { var customer1 = new Customer { Name = "John Smith" }; customer1.AddOrder(new Order { Reference = "ABC123" }); return new IndexViewModel { Customers = new[] { customer1 } }; } } public class IndexInputModel { } public class IndexViewModel { public IEnumerable<Customer> Customers { get; set; } } public class IndexView : FubuPage<IndexViewModel> { } public class CustomerPartial : FubuControl<Customer> { } public class OrderPartial : FubuControl<Order> { } IndexView.aspx: (standard html stuff trimmed) <div> <%= this.PartialForEach(x => x.Customers).Using<CustomerPartial>() %> </div> CustomerPartial.ascx: <%@ Control Language="C#" Inherits="FubuDemo.Controllers.Customers.CustomerPartial" %> <div> Customer Name: <%= this.DisplayFor(x => x.Name) %> <br /> Orders: (<%= Model.Orders.Count() %>) <br /> <%= this.PartialForEach(x => x.Orders) %> </div> OrderPartial.ascx: <%@ Control Language="C#" Inherits="FubuDemo.Controllers.Customers.OrderPartial" %> <div> Order <br /> Ref: <%= this.DisplayFor(x => x.Reference) %> </div> When I view Customers/Index, I see the following: Customers Customer Name: John Smith Orders: (1) It seems that in CustomerPartial.ascx, doing Model.Orders.Count() correctly picks up that 1 order exists. However PartialForEach(x = x.Orders) does not, as nothing is rendered for the order. If I set a breakpoint on the Order constructor, I see that it initially gets called by the Index method on CustomersController, but then it gets called by FubuMVC.Core.Models.StandardModelBinder.Bind, so it is getting re-instantiated by FubuMVC and losing the content of the Orders collection. This isn't quite what I'd expect, I would think that PartialForEach would just pass the domain object directly into the partial. Am I missing the point somewhere? What is the 'correct' way to achieve this kind of result in Fubu?

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  • merge 2 php arrays which aren't of the same length by value

    - by Iain Urquhart
    Excuse me if this has indeed been asked before, I couldn't see anything that fitted my needs out of the dozens of similar titled posts out there ;) I'm trying to merge 2 php arrays which aren't of the same length, and merge them on a value that exists from identical key = values within both arrays. My first query produces an array from a nested set: array ( 1 => array ( 'node_id' => 1, 'lft' => 1, 'rgt' => 4, 'moved' => 0, 'label' => 'Home', 'entry_id' => 1, 'template_path' => '', 'custom_url' => '/', 'extra' => '', 'childs' => 1, 'level' => 0, 'lower' => 0, 'upper' => 0 ), 2 => array ( 'node_id' => 2, 'lft' => 2, 'rgt' => 3, 'moved' => 0, 'label' => 'Home', 'entry_id' => NULL, 'template_path' => '', 'custom_url' => 'http://google.com/', 'extra' => '', 'childs' => 0, 'level' => 1, 'lower' => 0, 'upper' => 0 ) ); My second array returns some additional key/values I'd like to insert to the above array: array ( 'entry_id' => 1, 'entry_title' => 'This is my title', ); I want to merge both of the arrays inserting the additional information into those that match on the key 'entry_id', as well as keeping the sub arrays which don't match. So, by combining the two arrays, I'd end up with array ( 1 => array ( 'node_id' => 1, 'lft' => 1, 'rgt' => 4, 'moved' => 0, 'label' => 'Home', 'entry_id' => 1, 'template_path' => '', 'custom_url' => '/', 'extra' => '', 'childs' => 1, 'level' => 0, 'lower' => 0, 'upper' => 0, 'entry_title' => 'This is my title' ), 2 => array ( 'node_id' => 2, 'lft' => 2, 'rgt' => 3, 'moved' => 0, 'label' => 'Home', 'entry_id' => NULL, 'template_path' => '', 'custom_url' => 'http://google.com/', 'extra' => '', 'childs' => 0, 'level' => 1, 'lower' => 0, 'upper' => 0, 'entry_title' => NULL ) ); Actually, writing this out makes me think I should do it via sql... Any help/advice greatly appreciated...

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  • Insert a transformed integer_sequence into a variadic template argument?

    - by coderforlife
    How do you insert a transformed integer_sequence (or similar since I am targeting C++11) into a variadic template argument? For example I have a class that represents a set of bit-wise flags (shown below). It is made using a nested-class because you cannot have two variadic template arguments for the same class. It would be used like typedef Flags<unsigned char, FLAG_A, FLAG_B, FLAG_C>::WithValues<0x01, 0x02, 0x04> MyFlags. Typically, they will be used with the values that are powers of two (although not always, in some cases certain combinations would be made, for example one could imagine a set of flags like Read=0x1, Write=0x2, and ReadWrite=0x3=0x1|0x2). I would like to provide a way to do typedef Flags<unsigned char, FLAG_A, FLAG_B, FLAG_C>::WithDefaultValues MyFlags. template<class _B, template <class,class,_B> class... _Fs> class Flags { public: template<_B... _Vs> class WithValues : public _Fs<_B, Flags<_B,_Fs...>::WithValues<_Vs...>, _Vs>... { // ... }; }; I have tried the following without success (placed inside the Flags class, outside the WithValues class): private: struct _F { // dummy class which can be given to a flag-name template template <_B _V> inline constexpr explicit _F(std::integral_constant<_B, _V>) { } }; // we count the flags, but only in a dummy way static constexpr unsigned _count = sizeof...(_Fs<_B, _F, 1>); static inline constexpr _B pow2(unsigned exp, _B base = 2, _B result = 1) { return exp < 1 ? result : pow2(exp/2, base*base, (exp % 2) ? result*base : result); } template <_B... _Is> struct indices { using next = indices<_Is..., sizeof...(_Is)>; using WithPow2Values = WithValues<pow2(_Is)...>; }; template <unsigned N> struct build_indices { using type = typename build_indices<N-1>::type::next; }; template <> struct build_indices<0> { using type = indices<>; }; //// Another attempt //template < _B... _Is> struct indices { // using WithPow2Values = WithValues<pow2(_Is)...>; //}; //template <unsigned N, _B... _Is> struct build_indices // : build_indices<N-1, N-1, _Is...> { }; //template < _B... _Is> struct build_indices<0, _Is...> // : indices<_Is...> { }; public: using WithDefaultValues = typename build_indices<_count>::type::WithPow2Values; Of course, I would be willing to have any other alternatives to the whole situation (supporting both flag names and values in the same template set, etc). I have included a "working" example at ideone: http://ideone.com/NYtUrg - by "working" I mean compiles fine without using default values but fails with default values (there is a #define to switch between them). Thanks!

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  • show hidden div tag from another page

    - by neueweblernen
    I'm trying to link to an all-inclusive FAQ page from various pages. The answers are contained in tags, nested within a line item of an unordered list housed by categories. The FAQ page has the following categories: Practical Nurse Exam Online Renewal Practice Hours etc. Under Practical Nurse Exam, there are sub categories, subjects, with questions below in tags that expand onClick. (e.g. Examination Day, Exam Results, etc.) Let's say I'm on a different page called Registration and there's a link to the FAQs for Exam Results. I'm able to link to the page and included the hashtag on the anchor or Exam Results, but it does not expand the subcategory. I've read this thread but it didn't work for me. Please help! The code is below: <script type="text/javascript"> function toggle(Info,pic) { var CState = document.getElementById(Info); CState.style.display = (CState.style.display != 'block') ? 'block' : 'none'; } window.onload = function() { var hash = window.location.hash; // would be "#div1" or something if(hash != "") { var id = hash.substr(1); // get rid of # document.getElementById(id).style.display = 'block'; } } </script> <style type="text/css"> .FAQ { cursor:hand; cursor:pointer; } .FAA { display:none; padding-left:20px; text-indent:-20px; } #FAQlist li { list-style-type: none; } #FAQlist ul { margin-left:0px; } headingOne{ font-family:Arial, Helvetica, sans-serif; color:#66BBFF; font-size:20px; font-weight:bold;} </style> Here's the body (part of it anyway) <headingOne class="FAQ" onClick="toggle('CPNRE', this)">PRACTICAL NURSE EXAM</headingOne> <div class="FAA" id="CPNRE"> <h3><a name="applying">Applying to write the CPNRE</a></h3> <ul id="FAQlist" style="width:450px;"> <li class="FAQ"> <p onclick="toggle('faq1',this)"> <strong>Q: How much does it cost to write the exam?</strong></p> <div class="FAA" id="faq1"> <b>A.</b> In 2013, the cost for the first exam writing is $600.00 which includes the interim license fee. See <a href="https://www.clpnbc.org/What-is-an-LPN/Becoming-an-LPN/Canadian-Practical-Nurse-Registration-Examination/Fees-and-Deadlines.aspx"> fee schedule</a>.</div> <hr /> </li> and here's the body of the other page that contains the link and the same script syntax as the all-inclusive FAQ page. This is just a test, that's not exactly what it will say: <a onclick="toggle('CPNRE', this)" href="file:///S|/Designs/Web stuff/FAQ all inclusive.html#applying"> click here</a>

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  • Effective optimization strategies on modern C++ compilers

    - by user168715
    I'm working on scientific code that is very performance-critical. An initial version of the code has been written and tested, and now, with profiler in hand, it's time to start shaving cycles from the hot spots. It's well-known that some optimizations, e.g. loop unrolling, are handled these days much more effectively by the compiler than by a programmer meddling by hand. Which techniques are still worthwhile? Obviously, I'll run everything I try through a profiler, but if there's conventional wisdom as to what tends to work and what doesn't, it would save me significant time. I know that optimization is very compiler- and architecture- dependent. I'm using Intel's C++ compiler targeting the Core 2 Duo, but I'm also interested in what works well for gcc, or for "any modern compiler." Here are some concrete ideas I'm considering: Is there any benefit to replacing STL containers/algorithms with hand-rolled ones? In particular, my program includes a very large priority queue (currently a std::priority_queue) whose manipulation is taking a lot of total time. Is this something worth looking into, or is the STL implementation already likely the fastest possible? Along similar lines, for std::vectors whose needed sizes are unknown but have a reasonably small upper bound, is it profitable to replace them with statically-allocated arrays? I've found that dynamic memory allocation is often a severe bottleneck, and that eliminating it can lead to significant speedups. As a consequence I'm interesting in the performance tradeoffs of returning large temporary data structures by value vs. returning by pointer vs. passing the result in by reference. Is there a way to reliably determine whether or not the compiler will use RVO for a given method (assuming the caller doesn't need to modify the result, of course)? How cache-aware do compilers tend to be? For example, is it worth looking into reordering nested loops? Given the scientific nature of the program, floating-point numbers are used everywhere. A significant bottleneck in my code used to be conversions from floating point to integers: the compiler would emit code to save the current rounding mode, change it, perform the conversion, then restore the old rounding mode --- even though nothing in the program ever changed the rounding mode! Disabling this behavior significantly sped up my code. Are there any similar floating-point-related gotchas I should be aware of? One consequence of C++ being compiled and linked separately is that the compiler is unable to do what would seem to be very simple optimizations, such as move method calls like strlen() out of the termination conditions of loop. Are there any optimization like this one that I should look out for because they can't be done by the compiler and must be done by hand? On the flip side, are there any techniques I should avoid because they are likely to interfere with the compiler's ability to automatically optimize code? Lastly, to nip certain kinds of answers in the bud: I understand that optimization has a cost in terms of complexity, reliability, and maintainability. For this particular application, increased performance is worth these costs. I understand that the best optimizations are often to improve the high-level algorithms, and this has already been done.

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  • C++ - getline() keeps reading the same line over and over again for some reason

    - by Jammanuser
    I am wondering WTF my while loop which calls istream& getline ( istream& is, string& str ); keeps reading the same line again. I have the following while loop (nested down several levels of other while loops and if statements) which calls getline, but my output statement which is the first code line in the while loop's block of code tells me it is reading the same line over and over again, which explains why my output file doesn't contain the right data when my program is finished. while (getline(file_handle, buffer_str)) { cout<< buffer_str <<endl; cin.get(); if ((buffer_str.find(';', 0) != string::npos) && (buffer_str.find('\"', 0) != string::npos)) { //we're now at the end of the 'exc' initialiation statement buffer_str.erase(buffer_str.size() - 2, 1); buffer_str += '\n'; for (size_t i = 0; i < pos; i++) { buffer_str += ' '; } buffer_str += "throw(exc);\n"; for (size_t i = 0; i < (pos - 3); i++) { buffer_str += ' '; } buffer_str += '}'; } else if (buffer_str.find(search_str6, 0) != string::npos) { //we're now at the second problem line of the first case buffer_str += " {\n"; output_str += buffer_str; output_str += '\n'; getline(file_handle, buffer_str); //We're now at the beginning of the 'exc' initialiation statement output_str += buffer_str; output_str += '\n'; while (getline(file_handle, buffer_str)) { if ((buffer_str.find(';', 0) != string::npos) && (buffer_str.find('\"', 0) != string::npos)) { //we're now at the end of the 'exc' initialiation statement buffer_str.erase(buffer_str.size() - 2, 1); buffer_str += '\n'; for (size_t i = 0; i < pos; i++) { buffer_str += ' '; } buffer_str += "throw(exc);\n"; for (size_t i = 0; i < (pos - 3); i++) { buffer_str += ' '; } buffer_str += '}'; } output_str += buffer_str; output_str += '\n'; if (buffer_str.find("return", 0) != string::npos) { getline(file_handle, buffer_str); output_str += buffer_str; output_str += '\n'; about_to_break = true; break; //out of this while loop } } } if (about_to_break) { break; //out of the level 3 while loop (execution then goes back up to beginning of level 2 while loop) } output_str += buffer_str; output_str += '\n'; } Because of this problem, my if statement and then my else statement in my loop are not functioning as they should, and it doesn't break out of that loop when it should (though it eventually does break out of it, but I don't know exactly how yet). Anyone have any idea what could be causing this problem?? Thanks in advance.

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  • CSS + jQuery - Unable to perform .toggle() and repeated jQueryTemplate Item [I must warn you this is a bit overwhelming]

    - by user1027620
    Okay here we go: Stream.html (Template file) <div class="streamItem clearfix"> <input type="button" /> <div class="clientStrip"> <img src="" alt="${Sender}" /> </div> <div class="clientView"> <a href="#" class="clientName">${Sender}</a> <p>${Value}</p> <p>${DateTime}</p> <div class="itemGadgets"> <ul> <li class="toggleInput">Value</li> <li></li> </ul> </div> <div class="inputContainer"> <input type="text" value="" /> </div> </div> </div> <div class="spacer" /> Default.aspx (jQuery) $('.toggleInput').live('click', function () { $(this).parent().parent() .find('.inputContainer').toggle(); $(this).parent().parent().find('.inputContainer') .find('input[type=text]').focus(); }); Update: The above has been changed to: $('.toggleInput').live('click', function () { $(this).closest(".clientView").find(".inputContainer").toggle() $(this).closest(".clientView").find(".inputContainer") .find('input[type=text]').focus(); }); Issues with jQuery: I have comments that belong to each .streamItem. My previous solution was to use ListView control as follows: <ItemTemplate> <asp:Panel ID="StreamItem" CssClass="StreamItem" runat="server"> ... <!-- Insert another nested ListView control here to load the comments for the parent stream. --> So as you can see, this is not a solution since I started using jQuery Templates and I am fetching the data using the following jQuery $.ajax method: $.ajax({ type: 'POST', url: 'Services.asmx/GetStream', data: "{}", contentType: 'application/json', success: function (Stream) { $.get('Templates/Stream.html', function (template) { $.tmpl(template, Stream.d).appendTo("#Stream"); }); } }); How can I resolve this without using the old ListView solution but by using jQuery Templates to load the comments whenever I am getting data for a specific stream? I am using a simple WebMethod to return my data as follows: [WebMethod] public List<Stream> GetStream() { List<Stream> Streams = Stream.GetRange(X, X, HttpContext.Current.User.Identity.Name); return Streams; } I am looking for a way to handle the .toggleInput click event. I need check if .Comments (a main container for the (to be comments container <div>)) has children (or more than one .commentItem). If so, then I need to show that .inputContainer and hide all the other .inputContainer divs with .Comments size() == 0 if they're visible. Please see the image below: Default.aspx (Partial CSS) div.streamItem div.clientView { float : left; width : 542px; } div.streamItem div.clientView p { margin : 5px 0 0 0; font-size : 10pt; } div.streamItem div.clientView div.inputContainer { display : none; /* Doesn't hide .inputContainer */ padding : 2px; background-color : #f1f1f1; } Issues with CSS: On page load, display: none; has no effect. That's it! If you're reading this I'd like to thank you for your time and thoughts! :)

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  • Testing for Adjacent Cells In a Multi-level Grid

    - by Steve
    I'm designing an algorithm to test whether cells on a grid are adjacent or not. The catch is that the cells are not on a flat grid. They are on a multi-level grid such as the one drawn below. Level 1 (Top Level) | - - - - - | | A | B | C | | - - - - - | | D | E | F | | - - - - - | | G | H | I | | - - - - - | Level 2 | -Block A- | -Block B- | | 1 | 2 | 3 | 1 | 2 | 3 | | - - - - - | - - - - - | | 4 | 5 | 6 | 4 | 5 | 6 | ... | - - - - - | - - - - - | | 7 | 8 | 9 | 7 | 8 | 9 | | - - - - - | - - - - - | | -Block D- | -Block E- | | 1 | 2 | 3 | 1 | 2 | 3 | | - - - - - | - - - - - | | 4 | 5 | 6 | 4 | 5 | 6 | ... | - - - - - | - - - - - | | 7 | 8 | 9 | 7 | 8 | 9 | | - - - - - | - - - - - | . . . . . . This diagram is simplified from my actual need but the concept is the same. There is a top level block with many cells within it (level 1). Each block is further subdivided into many more cells (level 2). Those cells are further subdivided into level 3, 4 and 5 for my project but let's just stick to two levels for this question. I'm receiving inputs for my function in the form of "A8, A9, B7, D3". That's a list of cell Ids where each cell Id has the format (level 1 id)(level 2 id). Let's start by comparing just 2 cells, A8 and A9. That's easy because they are in the same block. private static RelativePosition getRelativePositionInTheSameBlock(String v1, String v2) { RelativePosition relativePosition; if( v1-v2 == -1 ) { relativePosition = RelativePosition.LEFT_OF; } else if (v1-v2 == 1) { relativePosition = RelativePosition.RIGHT_OF; } else if (v1-v2 == -BLOCK_WIDTH) { relativePosition = RelativePosition.TOP_OF; } else if (v1-v2 == BLOCK_WIDTH) { relativePosition = RelativePosition.BOTTOM_OF; } else { relativePosition = RelativePosition.NOT_ADJACENT; } return relativePosition; } An A9 - B7 comparison could be done by checking if A is a multiple of BLOCK_WIDTH and whether B is (A-BLOCK_WIDTH+1). Either that or just check naively if the A/B pair is 3-1, 6-4 or 9-7 for better readability. For B7 - D3, they are not adjacent but D3 is adjacent to A9 so I can do a similar adjacency test as above. So getting away from the little details and focusing on the big picture. Is this really the best way to do it? Keeping in mind the following points: I actually have 5 levels not 2, so I could potentially get a list like "A8A1A, A8A1B, B1A2A, B1A2B". Adding a new cell to compare still requires me to compare all the other cells before it (seems like the best I could do for this step is O(n)) The cells aren't all 3x3 blocks, they're just that way for my example. They could be MxN blocks with different M and N for different levels. In my current implementation above, I have separate functions to check adjacency if the cells are in the same blocks, if they are in separate horizontally adjacent blocks or if they are in separate vertically adjacent blocks. That means I have to know the position of the two blocks at the current level before I call one of those functions for the layer below. Judging by the complexity of having to deal with mulitple functions for different edge cases at different levels and having 5 levels of nested if statements. I'm wondering if another design is more suitable. Perhaps a more recursive solution, use of other data structures, or perhaps map the entire multi-level grid to a single-level grid (my quick calculations gives me about 700,000+ atomic cell ids). Even if I go that route, mapping from multi-level to single level is a non-trivial task in itself.

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  • How to Create Auto Playlists in Windows Media Player 12

    - by DigitalGeekery
    Are you getting tired of the same old playlists in Windows Media Player? Today we’ll show you how to create dynamic auto playlists based on criteria you choose in WMP 12 in Windows 7. Auto Playlists In Library view, click on Create playlist dropdown arrow and select Create auto playlist. On the New Auto Playlist window type in a name for the playlist in the text box. Now we need to choose our criteria by which to filter your playlist. Select Click here to add criteria. For our example, we will create a playlist of songs that were added to the library in the last week from the Alternative genre. So, we will first select Date Added from the dropdown list. Many criteria will have addition options to configure. In the example below you will see that we have a few options to fine tune.   We will filter all the songs added to the library in the last 7 days. We will select Is After from the first dropdown list. Then select Last 7 Days from the second dropdown list. You can add multiple criteria to further filter your playlist. If you can’t find the criteria you are looking for, select “More” at the bottom of the dropdown list.   This will pull up a filter window with all the criteria. Select a filter and then click OK when finished.   From the Genre dropdown, we will select Alternative. If you’d like to add Pictures, Videos, or TV Shows to your auto playlists you can do so by selecting them from the dropdown list under And also include. You will then be able to select criteria for your pictures, videos, or TV shows from the dropdown list.   Finally, you can also add restrictions to your music such as the number of items, duration, or total size. We will limit the duration of our playlist to one hour by selecting Limit Total Duration To… Then type in 1 hour…Click OK.   Our library is automatically filtered and a playlist is created based on the criteria we selected. When additional songs are added to the Windows Media Player library, any of new songs that fit the criteria will automatically be added to the New Songs playlist. You can also save a copy of an auto playlist as a regular playlist. Switch to Playlists view by clicking Playlists from either the top menu or the navigation bar. Select the Play tab and then click Clear list to remove any tracks from the list pane.   Right-click on the playlist you want to save, select Add to, and then Play list. The songs from your auto playlist will appear as an Unsaved list on the list pane. Click Save list. Type in a name for your playlist. Your auto playlist will continue to change as you add or remove items from your Media Player library that meet the criteria you established. The new saved playlist we just created will stay as it is currently. Editing a Auto playlist is easy. Right-click on the playlist and select Edit. Now you are ready to enjoy your playlist. Conclusion Auto playlists are great way to keep your playlists fresh in Windows Media Player 12. Users can get creative and experiment with the wide variety of criteria to customize their listening experience. If you are new to playlists in Windows Media Player, you may want to check our our previous post on how to create custom playlists in Windows Media Player 12. Are you looking to get better sound from WMP 12? Take a look at how to improve playback using enhancements in Windows Media Player 12. Similar Articles Productive Geek Tips Create Custom Playlists in Windows Media Player 12Fixing When Windows Media Player Library Won’t Let You Add FilesInstall and Use the VLC Media Player on Ubuntu LinuxMake Windows Media Player Automatically Open in Mini Player ModeMake VLC Player Look like Windows Media Player 10 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips VMware Workstation 7 Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Error Goblin Explains Windows Error Codes Twelve must-have Google Chrome plugins Cool Looking Skins for Windows Media Player 12 Move the Mouse Pointer With Your Face Movement Using eViacam Boot Windows Faster With Boot Performance Diagnostics Create Ringtones For Your Android Phone With RingDroid

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  • ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager

    - by rajbk
    This post walks you through creating a UI for paging, sorting and filtering a list of data items. It makes use of the excellent MVCContrib Grid and Pager Html UI helpers. A sample project is attached at the bottom. Our UI will eventually look like this. The application will make use of the Northwind database. The top portion of the page has a filter area region. The filter region is enclosed in a form tag. The select lists are wired up with jQuery to auto post back the form. The page has a pager region at the top and bottom of the product list. The product list has a link to display more details about a given product. The column headings are clickable for sorting and an icon shows the sort direction. Strongly Typed View Models The views are written to expect strongly typed objects. We suffix these strongly typed objects with ViewModel since they are designed specifically for passing data down to the view.  The following listing shows the ProductViewModel. This class will be used to hold information about a Product. We use attributes to specify if the property should be hidden and what its heading in the table should be. This metadata will be used by the MvcContrib Grid to render the table. Some of the properties are hidden from the UI ([ScaffoldColumn(false)) but are needed because we will be using those for filtering when writing our LINQ query. public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) {   var productList = productRepository.GetProductsProjected();   // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; }   // Filter on SupplierID if (supplierID.HasValue) { productList = productList.Where(a => a.SupplierID == supplierID); }   // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); }   // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); }   // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill();   // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10);     var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions };   return View(productListContainer); } The following diagram shows the rest of the key ViewModels in our design. We have a container class called ProductListContainerViewModel which has nested classes. The ProductPagedList is of type IPagination<ProductViewModel>. The MvcContrib expects the IPagination<T> interface to determine the page number and page size of the collection we are working with. You convert any IEnumerable<T> into an IPagination<T> by calling the AsPagination extension method in the MvcContrib library. It also creates a paged set of type ProductViewModel. The ProductFilterViewModel class will hold information about the different select lists and the ProductName being searched on. It will also hold state of any previously selected item in the lists and the previous search criteria (you will recall that this type of state information was stored in Viewstate when working with WebForms). With MVC there is no state storage and so all state has to be fetched and passed back to the view. The GridSortOptions is a type defined in the MvcContrib library and is used by the Grid to determine the current column being sorted on and the current sort direction. The following shows the view and partial views used to render our UI. The Index view expects a type ProductListContainerViewModel which we described earlier. <%Html.RenderPartial("SearchFilters", Model.ProductFilterViewModel); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> <% Html.RenderPartial("SearchResults", Model); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> The View contains a partial view “SearchFilters” and passes it the ProductViewFilterContainer. The SearchFilter uses this Model to render all the search lists and textbox. The partial view “Pager” uses the ProductPageList which implements the interface IPagination. The “Pager” view contains the MvcContrib Pager helper used to render the paging information. This view is repeated twice since we want the pager UI to be available at the top and bottom of the product list. The Pager partial view is located in the Shared directory so that it can be reused across Views. The partial view “SearchResults” uses the ProductListContainer model. This partial view contains the MvcContrib Grid which needs both the ProdctPagedList and GridSortOptions to render itself. The Controller Action An example of a request like this: /Products?productName=test&supplierId=29&categoryId=4. The application receives this GET request and maps it to the Index method of the ProductController. Within the action we create an IQueryable<ProductViewModel> by calling the GetProductsProjected() method. /// <summary> /// This method takes in a filter list, paging/sort options and applies /// them to an IQueryable of type ProductViewModel /// </summary> /// <returns> /// The return object is a container that holds the sorted/paged list, /// state for the fiters and state about the current sorted column /// </returns> public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) {   var productList = productRepository.GetProductsProjected();   // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; }   // Filter on SupplierID if (supplierID.HasValue) { productList.Where(a => a.SupplierID == supplierID); }   // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); }   // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); }   // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill();   // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10);     var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions };   return View(productListContainer); } The supplier, category and productname filters are applied to this IQueryable if any are present in the request. The ProductPagedList class is created by applying a sort order and calling the AsPagination method. Finally the ProductListContainerViewModel class is created and returned to the view. You have seen how to use strongly typed views with the MvcContrib Grid and Pager to render a clean lightweight UI with strongly typed views. You also saw how to use partial views to get data from the strongly typed model passed to it from the parent view. The code also shows you how to use jQuery to auto post back. The sample is attached below. Don’t forget to change your connection string to point to the server containing the Northwind database. NorthwindSales_MvcContrib.zip My name is Kobayashi. I work for Keyser Soze.

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  • Mapping UrlEncoded POST Values in ASP.NET Web API

    - by Rick Strahl
    If there's one thing that's a bit unexpected in ASP.NET Web API, it's the limited support for mapping url encoded POST data values to simple parameters of ApiController methods. When I first looked at this I thought I was doing something wrong, because it seems mighty odd that you can bind query string values to parameters by name, but can't bind POST values to parameters in the same way. To demonstrate here's a simple example. If you have a Web API method like this:[HttpGet] public HttpResponseMessage Authenticate(string username, string password) { …} and then hit with a URL like this: http://localhost:88/samples/authenticate?Username=ricks&Password=sekrit it works just fine. The query string values are mapped to the username and password parameters of our API method. But if you now change the method to work with [HttpPost] instead like this:[HttpPost] public HttpResponseMessage Authenticate(string username, string password) { …} and hit it with a POST HTTP Request like this: POST http://localhost:88/samples/authenticate HTTP/1.1 Host: localhost:88 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Content-type: application/x-www-form-urlencoded Content-Length: 30 Username=ricks&Password=sekrit you'll find that while the request works, it doesn't actually receive the two string parameters. The username and password parameters are null and so the method is definitely going to fail. When I mentioned this over Twitter a few days ago I got a lot of responses back of why I'd want to do this in the first place - after all HTML Form submissions are the domain of MVC and not WebAPI which is a valid point. However, the more common use case is using POST Variables with AJAX calls. The following is quite common for passing simple values:$.post(url,{ Username: "Rick", Password: "sekrit" },function(result) {…}); but alas that doesn't work. How ASP.NET Web API handles Content Bodies Web API supports parsing content data in a variety of ways, but it does not deal with multiple posted content values. In effect you can only post a single content value to a Web API Action method. That one parameter can be very complex and you can bind it in a variety of ways, but ultimately you're tied to a single POST content value in your parameter definition. While it's possible to support multiple parameters on a POST/PUT operation, only one parameter can be mapped to the actual content - the rest have to be mapped to route values or the query string. Web API treats the whole request body as one big chunk of data that is sent to a Media Type Formatter that's responsible for de-serializing the content into whatever value the method requires. The restriction comes from async nature of Web API where the request data is read only once inside of the formatter that retrieves and deserializes it. Because it's read once, checking for content (like individual POST variables) first is not possible. However, Web API does provide a couple of ways to access the form POST data: Model Binding - object property mapping to bind POST values FormDataCollection - collection of POST keys/values ModelBinding POST Values - Binding POST data to Object Properties The recommended way to handle POST values in Web API is to use Model Binding, which maps individual urlencoded POST values to properties of a model object provided as the parameter. Model binding requires a single object as input to be bound to the POST data, with each POST key that matches a property name (including nested properties like Address.Street) being mapped and updated including automatic type conversion of simple types. This is a very nice feature - and a familiar one from MVC - that makes it very easy to have model objects mapped directly from inbound data. The obvious drawback with Model Binding is that you need a model for it to work: You have to provide a strongly typed object that can receive the data and this object has to map the inbound data. To rewrite the example above to use ModelBinding I have to create a class maps the properties that I need as parameters:public class LoginData { public string Username { get; set; } public string Password { get; set; } } and then accept the data like this in the API method:[HttpPost] public HttpResponseMessage Authenticate(LoginData login) { string username = login.Username; string password = login.Password; … } This works fine mapping the POST values to the properties of the login object. As a side benefit of this method definition, the method now also allows posting of JSON or XML to the same endpoint. If I change my request to send JSON like this: POST http://localhost:88/samples/authenticate HTTP/1.1 Host: localhost:88 Accept: application/jsonContent-type: application/json Content-Length: 40 {"Username":"ricks","Password":"sekrit"} it works as well and transparently, courtesy of the nice Content Negotiation features of Web API. There's nothing wrong with using Model binding and in fact it's a common practice to use (view) model object for inputs coming back from the client and mapping them into these models. But it can be  kind of a hassle if you have AJAX applications with a ton of backend hits, especially if many methods are very atomic and focused and don't effectively require a model or view. Not always do you have to pass structured data, but sometimes there are just a couple of simple response values that need to be sent back. If all you need is to pass a couple operational parameters, creating a view model object just for parameter purposes seems like overkill. Maybe you can use the query string instead (if that makes sense), but if you can't then you can often end up with a plethora of 'message objects' that serve no further  purpose than to make Model Binding work. Note that you can accept multiple parameters with ModelBinding so the following would still work:[HttpPost] public HttpResponseMessage Authenticate(LoginData login, string loginDomain) but only the object will be bound to POST data. As long as loginDomain comes from the querystring or route data this will work. Collecting POST values with FormDataCollection Another more dynamic approach to handle POST values is to collect POST data into a FormDataCollection. FormDataCollection is a very basic key/value collection (like FormCollection in MVC and Request.Form in ASP.NET in general) and then read the values out individually by querying each. [HttpPost] public HttpResponseMessage Authenticate(FormDataCollection form) { var username = form.Get("Username"); var password = form.Get("Password"); …} The downside to this approach is that it's not strongly typed, you have to handle type conversions on non-string parameters, and it gets a bit more complicated to test such as setup as you have to seed a FormDataCollection with data. On the other hand it's flexible and easy to use and especially with string parameters is easy to deal with. It's also dynamic, so if the client sends you a variety of combinations of values on which you make operating decisions, this is much easier to work with than a strongly typed object that would have to account for all possible values up front. The downside is that the code looks old school and isn't as self-documenting as a parameter list or object parameter would be. Nevertheless it's totally functionality and a viable choice for collecting POST values. What about [FromBody]? Web API also has a [FromBody] attribute that can be assigned to parameters. If you have multiple parameters on a Web API method signature you can use [FromBody] to specify which one will be parsed from the POST content. Unfortunately it's not terribly useful as it only returns content in raw format and requires a totally non-standard format ("=content") to specify your content. For more info in how FromBody works and several related issues to how POST data is mapped, you can check out Mike Stalls post: How WebAPI does Parameter Binding Not really sure where the Web API team thought [FromBody] would really be a good fit other than a down and dirty way to send a full string buffer. Extending Web API to make multiple POST Vars work? Don't think so Clearly there's no native support for multiple POST variables being mapped to parameters, which is a bit of a bummer. I know in my own work on one project my customer actually found this to be a real sticking point in their AJAX backend work, and we ended up not using Web API and using MVC JSON features instead. That's kind of sad because Web API is supposed to be the proper solution for AJAX backends. With all of ASP.NET Web API's extensibility you'd think there would be some way to build this functionality on our own, but after spending a bit of time digging and asking some of the experts from the team and Web API community I didn't hear anything that even suggests that this is possible. From what I could find I'd say it's not possible primarily because Web API's Routing engine does not account for the POST variable mapping. This means [HttpPost] methods with url encoded POST buffers are not mapped to the parameters of the endpoint, and so the routes would never even trigger a request that could be intercepted. Once the routing doesn't work there's not much that can be done. If somebody has an idea how this could be accomplished I would love to hear about it. Do we really need multi-value POST mapping? I think that that POST value mapping is a feature that one would expect of any API tool to have. If you look at common APIs out there like Flicker and Google Maps etc. they all work with POST data. POST data is very prominent much more so than JSON inputs and so supporting as many options that enable would seem to be crucial. All that aside, Web API does provide very nice features with Model Binding that allows you to capture many POST variables easily enough, and logistically this will let you build whatever you need with POST data of all shapes as long as you map objects. But having to have an object for every operation that receives a data input is going to take its toll in heavy AJAX applications, with a lot of types created that do nothing more than act as parameter containers. I also think that POST variable mapping is an expected behavior and Web APIs non-support will likely result in many, many questions like this one: How do I bind a simple POST value in ASP.NET WebAPI RC? with no clear answer to this question. I hope for V.next of WebAPI Microsoft will consider this a feature that's worth adding. Related Articles Passing multiple POST parameters to Web API Controller Methods Mike Stall's post: How Web API does Parameter Binding Where does ASP.NET Web API Fit?© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Ask How-To Geek: Dropbox in the Start Menu, Understanding Symlinks, and Ripping TV Series DVDs

    - by Jason Fitzpatrick
    This week we take a look at how to incorporate Dropbox into your Windows Start Menu, understanding and using symbolic links, and how to rip your TV series DVDs right to unique and high-quality episode files. Once a week we dip into our reader mailbag and help readers solve their problems, sharing the useful solutions with you in the process. Read on to see our fixes for this week’s reader dilemmas. Add Drobox to Your Start Menu Dear How-To Geek, I use Dropbox all the time and would like to add it right onto my start menu along side the other major shortcuts like Documents, Pictures, etc. It seems like adding Dropbox into the menu should be part of the Dropbox installation package! Sincerely, Dropboxing in Des Moines Dear Dropboxing, We agree, it would be a nice installation option. As it stands you’re going to have to do a little simple hacking to get Dropbox nestled neatly into your start menu. The hack isn’t super elegant but when you’re done you’ll have the link you want and it’ll look like it was there all along. Check out this step-by-step guide here in order to take an existing Library shortcut and rework it to be a Dropbox link. Understanding and Using Symbolic Links Dear How-To Geek, I was talking to a coworker the other day about an issue I’d been having with a media center application I’m running. He suggested using symbolic links to better organize my media and make it easier for the application to access my collection. I had no idea what he was talking about and never got a chance to bug him about it later. Can you clear up this whole symbolic links business for me? I’ve been using computers for years and I’ve never even heard of it! Sincerely, Symbolic Who? Dear Symbolic, Symbolic links aren’t commonly used by many Windows users which is why you likely haven’t run into the concept. Symbolic links are essentially supercharged shortcuts—the newly introduced Windows library system is really just a type of symbolic link system. You can use symbolic links to do all sorts of neat stuff like link folders to your Dropbox folder, organize media, and more. The concept of symbolic links is pretty simple but the execution can be really tricky. We’d suggest reading over our guide to creating symbolic links in Windows 7, Windows XP, and Ubunutu to get a clearer idea what you’re getting into. Rip Your TV DVDs into Handy Episode Files Dear How-To Geek, My wife got me an iPod for Christmas and I still haven’t got around to filling it up. I have tons of entire TV show seasons on DVD and would like to get them on the iPod but I have absolutely no idea where to start. How do I get the shows off the discs? I thought it would be as easy to import the TV shows into iTunes as it is to import tracks off a CD but I was totally wrong. I tried downloading some applications to rip them but those didn’t work at all. Very frustrating! Surely there is an easy and/or automated way to do this, right? Sincerely, Free My DVDs Dear DVDs, Oh man is this a frustration we can relate to. It’s inordinately difficult to get movies and TV shows off physical media and into digital (and portable media player-friendly) formats. There are a multitude of ways to rip DVDs and quite a few applications out there (some good, some mediocre, and some outright malware). We’d recommend a two-part punch to solve your ripping woes. You’ll need a copy of DVDFab to strip away the protections on the discs and rip the disc and Handbrake to load the disc image and convert the files. It’s not quite as smooth as the CD-to-iTunes workflow but it’s still pretty easy. Check out all the steps and settings you’ll want to toggle here. Have a question you want to put before the How-To Geek staff? Shoot us an email at [email protected] and then keep an eye out for a solution in the Ask How-To Geek column. Latest Features How-To Geek ETC Internet Explorer 9 RC Now Available: Here’s the Most Interesting New Stuff Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware How to Change the Default Application for Android Tasks Stop Believing TV’s Lies: The Real Truth About "Enhancing" Images The How-To Geek Valentine’s Day Gift Guide Inspire Geek Love with These Hilarious Geek Valentines Google’s New Personal Blocklist Extension Kills Search Engine Spam KeyCounter Tracks Your Keystrokes and Mouse Clicks Add Custom LED Ambient Lighting to Your PC or Media Center The Trackor Monitors Amazon Prices; Integrates with Chrome, Firefox, and Safari Four Awesome TRON Legacy Themes for Chrome and Iron Anger is Illogical – Old School Style Instructional Video [Star Trek Mashup]

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  • Parallelism in .NET – Part 2, Simple Imperative Data Parallelism

    - by Reed
    In my discussion of Decomposition of the problem space, I mentioned that Data Decomposition is often the simplest abstraction to use when trying to parallelize a routine.  If a problem can be decomposed based off the data, we will often want to use what MSDN refers to as Data Parallelism as our strategy for implementing our routine.  The Task Parallel Library in .NET 4 makes implementing Data Parallelism, for most cases, very simple. Data Parallelism is the main technique we use to parallelize a routine which can be decomposed based off data.  Data Parallelism refers to taking a single collection of data, and having a single operation be performed concurrently on elements in the collection.  One side note here: Data Parallelism is also sometimes referred to as the Loop Parallelism Pattern or Loop-level Parallelism.  In general, for this series, I will try to use the terminology used in the MSDN Documentation for the Task Parallel Library.  This should make it easier to investigate these topics in more detail. Once we’ve determined we have a problem that, potentially, can be decomposed based on data, implementation using Data Parallelism in the TPL is quite simple.  Let’s take our example from the Data Decomposition discussion – a simple contrast stretching filter.  Here, we have a collection of data (pixels), and we need to run a simple operation on each element of the pixel.  Once we know the minimum and maximum values, we most likely would have some simple code like the following: for (int row=0; row < pixelData.GetUpperBound(0); ++row) { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This simple routine loops through a two dimensional array of pixelData, and calls the AdjustContrast routine on each pixel. As I mentioned, when you’re decomposing a problem space, most iteration statements are potentially candidates for data decomposition.  Here, we’re using two for loops – one looping through rows in the image, and a second nested loop iterating through the columns.  We then perform one, independent operation on each element based on those loop positions. This is a prime candidate – we have no shared data, no dependencies on anything but the pixel which we want to change.  Since we’re using a for loop, we can easily parallelize this using the Parallel.For method in the TPL: Parallel.For(0, pixelData.GetUpperBound(0), row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); Here, by simply changing our first for loop to a call to Parallel.For, we can parallelize this portion of our routine.  Parallel.For works, as do many methods in the TPL, by creating a delegate and using it as an argument to a method.  In this case, our for loop iteration block becomes a delegate creating via a lambda expression.  This lets you write code that, superficially, looks similar to the familiar for loop, but functions quite differently at runtime. We could easily do this to our second for loop as well, but that may not be a good idea.  There is a balance to be struck when writing parallel code.  We want to have enough work items to keep all of our processors busy, but the more we partition our data, the more overhead we introduce.  In this case, we have an image of data – most likely hundreds of pixels in both dimensions.  By just parallelizing our first loop, each row of pixels can be run as a single task.  With hundreds of rows of data, we are providing fine enough granularity to keep all of our processors busy. If we parallelize both loops, we’re potentially creating millions of independent tasks.  This introduces extra overhead with no extra gain, and will actually reduce our overall performance.  This leads to my first guideline when writing parallel code: Partition your problem into enough tasks to keep each processor busy throughout the operation, but not more than necessary to keep each processor busy. Also note that I parallelized the outer loop.  I could have just as easily partitioned the inner loop.  However, partitioning the inner loop would have led to many more discrete work items, each with a smaller amount of work (operate on one pixel instead of one row of pixels).  My second guideline when writing parallel code reflects this: Partition your problem in a way to place the most work possible into each task. This typically means, in practice, that you will want to parallelize the routine at the “highest” point possible in the routine, typically the outermost loop.  If you’re looking at parallelizing methods which call other methods, you’ll want to try to partition your work high up in the stack – as you get into lower level methods, the performance impact of parallelizing your routines may not overcome the overhead introduced. Parallel.For works great for situations where we know the number of elements we’re going to process in advance.  If we’re iterating through an IList<T> or an array, this is a typical approach.  However, there are other iteration statements common in C#.  In many situations, we’ll use foreach instead of a for loop.  This can be more understandable and easier to read, but also has the advantage of working with collections which only implement IEnumerable<T>, where we do not know the number of elements involved in advance. As an example, lets take the following situation.  Say we have a collection of Customers, and we want to iterate through each customer, check some information about the customer, and if a certain case is met, send an email to the customer and update our instance to reflect this change.  Normally, this might look something like: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } } Here, we’re doing a fair amount of work for each customer in our collection, but we don’t know how many customers exist.  If we assume that theStore.GetLastContact(customer) and theStore.EmailCustomer(customer) are both side-effect free, thread safe operations, we could parallelize this using Parallel.ForEach: Parallel.ForEach(customers, customer => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } }); Just like Parallel.For, we rework our loop into a method call accepting a delegate created via a lambda expression.  This keeps our new code very similar to our original iteration statement, however, this will now execute in parallel.  The same guidelines apply with Parallel.ForEach as with Parallel.For. The other iteration statements, do and while, do not have direct equivalents in the Task Parallel Library.  These, however, are very easy to implement using Parallel.ForEach and the yield keyword. Most applications can benefit from implementing some form of Data Parallelism.  Iterating through collections and performing “work” is a very common pattern in nearly every application.  When the problem can be decomposed by data, we often can parallelize the workload by merely changing foreach statements to Parallel.ForEach method calls, and for loops to Parallel.For method calls.  Any time your program operates on a collection, and does a set of work on each item in the collection where that work is not dependent on other information, you very likely have an opportunity to parallelize your routine.

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  • XNA Notes 006

    - by George Clingerman
    If you used to think the XNA community was small and inactive, hopefully these XNA Notes are opening your eyes. And I honestly feel like I’m still only catching the tail end of everything that’s going on. It’s a large and active community and you can be so mired down in one part of it you miss all sorts of cool stuff another part is doing. XNA is many things to a lot of people and that makes for a lot of really awesome things going on. So here’s what I saw going on this last week! Time Critical XNA New: XNA Team - Peer Review now closes for XNA 3.1 games http://blogs.msdn.com/b/xna/archive/2011/02/08/peer-review-pipeline-closed-for-new-xna-gs-3-1-games-or-updates-on-app-hub.aspx http://twitter.com/XNACommunity/statuses/34649816529256448 The XNA Team posts about a meet up with Microsoft for Creator’s going to be at GDC, March 3rd at the Lobby Bar http://on.fb.me/fZungJ XNA Team: @mklucher is busying playing the the bubblegum on WP7 made by a member of the XNA team (although reportedly made in Silverlight? Crazy! ;) ) http://twitter.com/mklucher/statuses/34645662737895426 http://bubblegum.me Shawn Hargreaves posts multiple posts (is this a sign that something new is coming from the XNA team? Usually when Shawn has time to post, something has just wrapped up…) Random Shuffle http://blogs.msdn.com/b/shawnhar/archive/2011/02/09/random-shuffle.aspx Doing the right thing: resume, rewind or skip ahead http://blogs.msdn.com/b/shawnhar/archive/2011/02/10/doing-the-right-thing-resume-rewind-or-skip-ahead.aspx XNA Developers: Andrew Russel was on .NET Rocks recently talking with Carl and Richard about developing games for Xbox, iPhone and Android http://www.dotnetrocks.com/default.aspx?ShowNum=635 Eric W. releases the Fishing Girl source code into the wild http://ericw.ca/blog/posts/fishing-girl-now-open-source/ http://forums.create.msdn.com/forums/p/74642/454512.aspx#454512 BinaryTweedDeej reminds that XNA community that Indie City wants you involved http://twitter.com/BinaryTweedDeej/statuses/34596114028044288 http://www.indiecity.com Mike McLaughlin (@mikebmcl) releases his first two XNA articles on the TechNet wiki http://social.technet.microsoft.com/wiki/contents/articles/xna-framework-overview.aspx http://social.technet.microsoft.com/wiki/contents/articles/content-pipeline-overview.aspx John Watte plays around with the Content Pipeline and Music Visualization exploring just what can be done. http://www.enchantedage.com/xna-content-pipeline-fft-song-analysis http://www.enchantedage.com/fft-in-xna-content-pipeline-for-beat-detection-for-the-win Simon Stevens writes up his talk on Vector Collision Physics http://www.simonpstevens.com/News/VectorCollisionPhysics @domipheus puts together an XNA Task Manager http://www.flickr.com/photos/domipheus/5405603197/ MadNinjaSkillz releases his fork of Nick's Easy Storage component on CodePlex http://twitter.com/MadNinjaSkillz/statuses/34739039068229634 http://ezstorage.codeplex.com @ActiveNick was interviewed by Rob Cameron and discusses Windows Phone 7, Bing Maps and XNA http://twitter.com/ActiveNick/statuses/35348548526546944 http://msdn.microsoft.com/en-us/cc537546 Radiangames (Luke Schneider) posts about converting his games from XNA to Unity http://radiangames.com/?p=592 UberMonkey (@ElementCy) posts about a new project in the works, CubeTest a Minecraft style terrain http://www.ubergamermonkey.com/personal-projects/new-project-in-the-works/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Ubergamermonkey+%28UberGamerMonkey%29 Xbox LIVE Indie Games (XBLIG): VideoGamer Rob review Bonded Realities http://videogamerrob.wordpress.com/2011/02/05/xblig-review-bonded-realities/ XBLIG Round Up on Gamergeddon http://www.gamergeddon.com/2011/02/06/xbox-indie-game-round-up-february-6th/ Are gamers still rating Indie Games after the Xbox Dashboard update? http://www.gamemarx.com/news/2011/02/06/are-gamers-still-rating-indie-games-after-the-xbox-dashboard-update.aspx Joystiq - Xbox Live Indie Gems: Corrupted http://www.joystiq.com/2011/02/04/xbox-live-indie-gems-corrupted/ Raymond Matthews of DarkStarMatryx reviews (Almost) Total Mayhem and Aban Hawkins & the 1000 Spikes http://www.darkstarmatryx.com/?p=225 http://www.darkstarmatryx.com/?p=229 8 Bit Horse reviews Aban Hawkins & the 1000 spikes http://8bithorse.blogspot.com/2011/01/aban-hawkins-1000-spikes-xbl-indie.html 2010 wrap-up for FunInfused Games http://www.krissteele.net/blogdetails.aspx?id=245 NeoGaf roundup of January's XBLIGs http://www.neogaf.com/forum/showthread.php?t=420528 Armless Ocotopus interviews Michael Ventnor creator of Bonded Realities http://www.armlessoctopus.com/2011/02/07/interview-michael-ventnor-of-red-crest-studios/ @recharge_media posts about the new city music for Woodvale in Sin Rising http://rechargemedia.com/2011/02/08/new-city-theme-woodvale/ @DrMisty posts some footage of YoYoYo in action http://www.mstargames.co.uk/mistryblogmain/54-yoyoyoblogs/184-video-update.html Xona Games - Decimation X3 on Reviews on the Run http://video.citytv.com/video/detail/782443063001.000000/reviews-on-the-run--february-8-2011/g4/ @benkane gives an early peek at his action RPG coming to XBLIG http://www.youtube.com/watch?v=bDF_PrvtwU8 Rock, Paper Shotgun talks to Zeboyd games about bringing Cthulhu Saves the World to PC http://www.rockpapershotgun.com/2011/02/11/summoning-cthulhu-natter-with-zeboyd/ Xbox LIVE Indieverse interviews the creator of Bonded Realities http://xbl-indieverse.blogspot.com/2011/02/xbl-indieverse-interview-red-crest.html XNA Game Development: Dream-In-Code posts about an upcoming XNA Challenge/Coding contest http://www.dreamincode.net/forums/blog/1385/entry-3192-xna-challengecontest/ Sgt.Conker covers Fishing Girl and IndieFreaks Game Framework release http://www.sgtconker.com/2011/02/fishing-girl-did-not-sell-a-single-copy/ http://www.sgtconker.com/2011/02/indiefreaks-game-framework-v0-2-0-0/ @slyprid releases Transmute v0.40a with lots of new features and fixes http://twitter.com/slyprid/statuses/34125423067533312 http://twitter.com/slyprid/statuses/35326876243337216 http://forgottenstarstudios.com/ Jeff Brown writes an XNA 4.0 tutorial on Saving/Loading on the Xbox 360 http://www.robotfootgames.com/xna-tutorials/92-xna-tutorial-savingloading-on-xbox-360-40 XNA for Silverlight Developers: Part 3- Animation http://www.silverlightshow.net/items/XNA-for-Silverlight-developers-Part-3-Animation-transforms.aspx?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+xna-connection-twitter-specific-stream+%28XNA+Connection%27s+Twitter+specific+stream%29 The news from Nokia is definitely something XNA developers will want to keep their eye on http://blogs.forum.nokia.com/blog/nokia-developer-news/2011/02/11/letter-to-developers?sf1066337=1

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  • Mobile HCM: It’s not the future, it is right now

    - by Natalia Rachelson
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} A guest post by Steve Boese, Director Product Strategy, Oracle I’ll bet you reached for your iPhone or Android or BlackBerry and took a quick look at email or Facebook or last night’s text messages before you even got out of bed this morning. Come on, admit it, it’s ok, you are among friends here. See, feel better now? But seriously, the incredible growth and near-ubiquity of increasingly powerful, capable, and for many of us, essential in our daily lives mobile devices has profoundly changed the way we communicate, consume information, socialize, and more and more, conduct business and get our work done. And if you doubt that profound change has happened, just think for a moment about the last time you misplaced your iPhone.  The shivers, the cold sweats, the panic... We have all been there. And indeed your personal experiences with mobile technology echoes throughout the world - here are a few data points to consider: Market research firm IDC estimates 1.8 billion mobile phones will be shipped in 2012. A recent Pew study reports 46% of Americans own a smartphone of some kind. And finally in the USA, ownership of tablets like the iPad has doubled from 10% to 19% in the last year. So truly for the Human Resources leader, the question is no longer, ‘Should HR explore ways to exploit mobile devices and their always-on nature to better support and empower the modern workforce?’, but rather ‘How can HR best take advantage of smartphone and tablet capability to provide information, enable transactions, and enhance decision making?’. Because even though moving HCM applications to mobile devices seems inherently logical given today’s fast-moving and mobile workforces, and its promise to deliver incredible value to the organization, HR leaders also have to consider many factors before devising their Mobile HCM strategy and embarking on mobile HR technology projects. Here are just some of the important considerations for HR leaders as you build your strategies and evaluate mobile HCM solutions: Does your organization provide mobile devices to the workforce today, and if so, will the current set of deployed devices have the necessary capability and ecosystems to support your mobile HCM initiatives? Will you allow workers to use or bring their own mobile devices, (commonly abbreviated as ‘BYOD’), and if so are your IT and Security organizations in agreement and capable of supporting that strategy? Do you know which workers need access to mobile HCM applications? Often mobile HCM capability flows down in an organization, with executives and other ‘road-warrior’ types having the most immediate needs, followed by field sales staff, project managers, and even potential job candidates. But just as an organization will have to spend time understanding ‘who’ should have access to mobile HCM technology, the ‘what’ of the way the solutions should be deployed to these groups will also vary. What works and makes sense for the executive, (company-wide dashboards and analytics on an iPad), might not be as relevant for a retail store manager, (employee schedules, location-level sales and inventory data, transaction approvals, etc.). With Oracle Fusion HCM, we are taking an approach to mobile HR that encompasses not just the mobile solution needs for the various types of worker, but also incorporates the fundamental attributes of great mobile applications - the ability to support end-to-end transactions, apps that respond with lightning-fast speed, with functions that are embedded in a worker’s daily activities, and features that can be mashed-up easily with other business areas like Finance and CRM. Finally, and perhaps most importantly for the Oracle Fusion HCM team, delivering mobile experiences that truly enhance, enable, and empower the mobile workforce, and deliver on the design mantras of the best-in-class consumer applications, continues to shape and drive design decisions. Mobile is no longer the future, it is right now, and the cutting-edge HR leader of today will need to consider how mobile fits her HCM technology strategy from here on out. You can learn more about our ideas and plans for Oracle Fusion HCM mobile solutions at https://fusiontap.oracle.com/.

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  • Cleaner HTML Markup with ASP.NET 4 Web Forms - Client IDs (VS 2010 and .NET 4.0 Series)

    - by ScottGu
    This is the sixteenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. Today’s post is the first of a few blog posts I’ll be doing that talk about some of the important changes we’ve made to make Web Forms in ASP.NET 4 generate clean, standards-compliant, CSS-friendly markup.  Today I’ll cover the work we are doing to provide better control over the “ID” attributes rendered by server controls to the client. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Clean, Standards-Based, CSS-Friendly Markup One of the common complaints developers have often had with ASP.NET Web Forms is that when using server controls they don’t have the ability to easily generate clean, CSS-friendly output and markup.  Some of the specific complaints with previous ASP.NET releases include: Auto-generated ID attributes within HTML make it hard to write JavaScript and style with CSS Use of tables instead of semantic markup for certain controls (in particular the asp:menu control) make styling ugly Some controls render inline style properties even if no style property on the control has been set ViewState can often be bigger than ideal ASP.NET 4 provides better support for building standards-compliant pages out of the box.  The built-in <asp:> server controls with ASP.NET 4 now generate cleaner markup and support CSS styling – and help address all of the above issues.  Markup Compatibility When Upgrading Existing ASP.NET Web Forms Applications A common question people often ask when hearing about the cleaner markup coming with ASP.NET 4 is “Great - but what about my existing applications?  Will these changes/improvements break things when I upgrade?” To help ensure that we don’t break assumptions around markup and styling with existing ASP.NET Web Forms applications, we’ve enabled a configuration flag – controlRenderingCompatbilityVersion – within web.config that let’s you decide if you want to use the new cleaner markup approach that is the default with new ASP.NET 4 applications, or for compatibility reasons render the same markup that previous versions of ASP.NET used:   When the controlRenderingCompatbilityVersion flag is set to “3.5” your application and server controls will by default render output using the same markup generation used with VS 2008 and .NET 3.5.  When the controlRenderingCompatbilityVersion flag is set to “4.0” your application and server controls will strictly adhere to the XHTML 1.1 specification, have cleaner client IDs, render with semantic correctness in mind, and have extraneous inline styles removed. This flag defaults to 4.0 for all new ASP.NET Web Forms applications built using ASP.NET 4. Any previous application that is upgraded using VS 2010 will have the controlRenderingCompatbilityVersion flag automatically set to 3.5 by the upgrade wizard to ensure backwards compatibility.  You can then optionally change it (either at the application level, or scope it within the web.config file to be on a per page or directory level) if you move your pages to use CSS and take advantage of the new markup rendering. Today’s Cleaner Markup Topic: Client IDs The ability to have clean, predictable, ID attributes on rendered HTML elements is something developers have long asked for with Web Forms (ID values like “ctl00_ContentPlaceholder1_ListView1_ctrl0_Label1” are not very popular).  Having control over the ID values rendered helps make it much easier to write client-side JavaScript against the output, makes it easier to style elements using CSS, and on large pages can help reduce the overall size of the markup generated. New ClientIDMode Property on Controls ASP.NET 4 supports a new ClientIDMode property on the Control base class.  The ClientIDMode property indicates how controls should generate client ID values when they render.  The ClientIDMode property supports four possible values: AutoID—Renders the output as in .NET 3.5 (auto-generated IDs which will still render prefixes like ctrl00 for compatibility) Predictable (Default)— Trims any “ctl00” ID string and if a list/container control concatenates child ids (example: id=”ParentControl_ChildControl”) Static—Hands over full ID naming control to the developer – whatever they set as the ID of the control is what is rendered (example: id=”JustMyId”) Inherit—Tells the control to defer to the naming behavior mode of the parent container control The ClientIDMode property can be set directly on individual controls (or within container controls – in which case the controls within them will by default inherit the setting): Or it can be specified at a page or usercontrol level (using the <%@ Page %> or <%@ Control %> directives) – in which case controls within the pages/usercontrols inherit the setting (and can optionally override it): Or it can be set within the web.config file of an application – in which case pages within the application inherit the setting (and can optionally override it): This gives you the flexibility to customize/override the naming behavior however you want. Example: Using the ClientIDMode property to control the IDs of Non-List Controls Let’s take a look at how we can use the new ClientIDMode property to control the rendering of “ID” elements within a page.  To help illustrate this we can create a simple page called “SingleControlExample.aspx” that is based on a master-page called “Site.Master”, and which has a single <asp:label> control with an ID of “Message” that is contained with an <asp:content> container control called “MainContent”: Within our code-behind we’ll then add some simple code like below to dynamically populate the Label’s Text property at runtime:   If we were running this application using ASP.NET 3.5 (or had our ASP.NET 4 application configured to run using 3.5 rendering or ClientIDMode=AutoID), then the generated markup sent down to the client would look like below: This ID is unique (which is good) – but rather ugly because of the “ct100” prefix (which is bad). Markup Rendering when using ASP.NET 4 and the ClientIDMode is set to “Predictable” With ASP.NET 4, server controls by default now render their ID’s using ClientIDMode=”Predictable”.  This helps ensure that ID values are still unique and don’t conflict on a page, but at the same time it makes the IDs less verbose and more predictable.  This means that the generated markup of our <asp:label> control above will by default now look like below with ASP.NET 4: Notice that the “ct100” prefix is gone. Because the “Message” control is embedded within a “MainContent” container control, by default it’s ID will be prefixed “MainContent_Message” to avoid potential collisions with other controls elsewhere within the page. Markup Rendering when using ASP.NET 4 and the ClientIDMode is set to “Static” Sometimes you don’t want your ID values to be nested hierarchically, though, and instead just want the ID rendered to be whatever value you set it as.  To enable this you can now use ClientIDMode=static, in which case the ID rendered will be exactly the same as what you set it on the server-side on your control.  This will cause the below markup to be rendered with ASP.NET 4: This option now gives you the ability to completely control the client ID values sent down by controls. Example: Using the ClientIDMode property to control the IDs of Data-Bound List Controls Data-bound list/grid controls have historically been the hardest to use/style when it comes to working with Web Form’s automatically generated IDs.  Let’s now take a look at a scenario where we’ll customize the ID’s rendered using a ListView control with ASP.NET 4. The code snippet below is an example of a ListView control that displays the contents of a data-bound collection — in this case, airports: We can then write code like below within our code-behind to dynamically databind a list of airports to the ListView above: At runtime this will then by default generate a <ul> list of airports like below.  Note that because the <ul> and <li> elements in the ListView’s template are not server controls, no IDs are rendered in our markup: Adding Client ID’s to Each Row Item Now, let’s say that we wanted to add client-ID’s to the output so that we can programmatically access each <li> via JavaScript.  We want these ID’s to be unique, predictable, and identifiable. A first approach would be to mark each <li> element within the template as being a server control (by giving it a runat=server attribute) and by giving each one an id of “airport”: By default ASP.NET 4 will now render clean IDs like below (no ctl001-like ids are rendered):   Using the ClientIDRowSuffix Property Our template above now generates unique ID’s for each <li> element – but if we are going to access them programmatically on the client using JavaScript we might want to instead have the ID’s contain the airport code within them to make them easier to reference.  The good news is that we can easily do this by taking advantage of the new ClientIDRowSuffix property on databound controls in ASP.NET 4 to better control the ID’s of our individual row elements. To do this, we’ll set the ClientIDRowSuffix property to “Code” on our ListView control.  This tells the ListView to use the databound “Code” property from our Airport class when generating the ID: And now instead of having row suffixes like “1”, “2”, and “3”, we’ll instead have the Airport.Code value embedded within the IDs (e.g: _CLE, _CAK, _PDX, etc): You can use this ClientIDRowSuffix approach with other databound controls like the GridView as well. It is useful anytime you want to program row elements on the client – and use clean/identified IDs to easily reference them from JavaScript code. Summary ASP.NET 4 enables you to generate much cleaner HTML markup from server controls and from within your Web Forms applications.  In today’s post I covered how you can now easily control the client ID values that are rendered by server controls.  In upcoming posts I’ll cover some of the other markup improvements that are also coming with the ASP.NET 4 release. Hope this helps, Scott

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  • Entity Framework version 1- Brief Synopsis and Tips &ndash; Part 1

    - by Rohit Gupta
    To Do Eager loading use Projections (for e.g. from c in context.Contacts select c, c.Addresses)  or use Include Query Builder Methods (Include(“Addresses”)) If there is multi-level hierarchical Data then to eager load all the relationships use Include Query Builder methods like customers.Include("Order.OrderDetail") to include Order and OrderDetail collections or use customers.Include("Order.OrderDetail.Location") to include all Order, OrderDetail and location collections with a single include statement =========================================================================== If the query uses Joins then Include() Query Builder method will be ignored, use Nested Queries instead If the query does projections then Include() Query Builder method will be ignored Use Address.ContactReference.Load() OR Contact.Addresses.Load() if you need to Deferred Load Specific Entity – This will result in extra round trips to the database ObjectQuery<> cannot return anonymous types... it will return a ObjectQuery<DBDataRecord> Only Include method can be added to Linq Query Methods Any Linq Query method can be added to Query Builder methods. If you need to append a Query Builder Method (other than Include) after a LINQ method  then cast the IQueryable<Contact> to ObjectQuery<Contact> and then append the Query Builder method to it =========================================================================== Query Builder methods are Select, Where, Include Methods which use Entity SQL as parameters e.g. "it.StartDate, it.EndDate" When Query Builder methods do projection then they return ObjectQuery<DBDataRecord>, thus to iterate over this collection use contact.Item[“Name”].ToString() When Linq To Entities methods do projection, they return collection of anonymous types --- thus the collection is strongly typed and supports Intellisense EF Object Context can track changes only on Entities, not on Anonymous types. If you use a Defining Query for a EntitySet then the EntitySet becomes readonly since a Defining Query is the same as a View (which is treated as a ReadOnly by default). However if you want to use this EntitySet for insert/update/deletes then we need to map stored procs (as created in the DB) to the insert/update/delete functions of the Entity in the Designer You can use either Execute method or ToList() method to bind data to datasources/bindingsources If you use the Execute Method then remember that you can traverse through the ObjectResult<> collection (returned by Execute) only ONCE. In WPF use ObservableCollection to bind to data sources , for keeping track of changes and letting EF send updates to the DB automatically. Use Extension Methods to add logic to Entities. For e.g. create extension methods for the EntityObject class. Create a method in ObjectContext Partial class and pass the entity as a parameter, then call this method as desired from within each entity. ================================================================ DefiningQueries and Stored Procedures: For Custom Entities, one can use DefiningQuery or Stored Procedures. Thus the Custom Entity Collection will be populated using the DefiningQuery (of the EntitySet) or the Sproc. If you use Sproc to populate the EntityCollection then the query execution is immediate and this execution happens on the Server side and any filters applied will be applied in the Client App. If we use a DefiningQuery then these queries are composable, meaning the filters (if applied to the entityset) will all be sent together as a single query to the DB, returning only filtered results. If the sproc returns results that cannot be mapped to existing entity, then we first create the Entity/EntitySet in the CSDL using Designer, then create a dummy Entity/EntitySet using XML in the SSDL. When creating a EntitySet in the SSDL for this dummy entity, use a TSQL that does not return any results, but does return the relevant columns e.g. select ContactID, FirstName, LastName from dbo.Contact where 1=2 Also insure that the Entity created in the SSDL uses the SQL DataTypes and not .NET DataTypes. If you are unable to open the EDMX file in the designer then note the Errors ... they will give precise info on what is wrong. The Thrid option is to simply create a Native Query in the SSDL using <Function Name="PaymentsforContact" IsComposable="false">   <CommandText>SELECT ActivityId, Activity AS ActivityName, ImagePath, Category FROM dbo.Activities </CommandText></FuncTion> Then map this Function to a existing Entity. This is a quick way to get a custom Entity which is regular Entity with renamed columns or additional columns (which are computed columns). The disadvantage to using this is that It will return all the rows from the Defining query and any filter (if defined) will be applied only at the Client side (after getting all the rows from DB). If you you DefiningQuery instead then we can use that as a Composable Query. The Fourth option (for mapping a READ stored proc results to a non-existent Entity) is to create a View in the Database which returns all the fields that the sproc also returns, then update the Model so that the model contains this View as a Entity. Then map the Read Sproc to this View Entity. The other option would be to simply create the View and remove the sproc altogether. ================================================================ To Execute a SProc that does not return a entity, use a EntityCommand to execute that proc. You cannot call a sproc FunctionImport that does not return Entities From Code, the only way is to use SSDL function calls using EntityCommand.  This changes with EntityFramework Version 4 where you can return Scalar Types, Complex Types, Entities or NonQuery ================================================================ UDF when created as a Function in SSDL, we need to set the Name & IsComposable properties for the Function element. IsComposable is always false for Sprocs, for UDF's set this to true. You cannot call UDF "Function" from within code since you cannot import a UDF Function into the CSDL Model (with Version 1 of EF). only stored procedures can be imported and then mapped to a entity ================================================================ Entity Framework requires properties that are involved in association mappings to be mapped in all of the function mappings for the entity (Insert, Update and Delete). Because Payment has an association to Reservation... hence we need to pass both the paymentId and reservationId to the Delete sproc even though just the paymentId is the PK on the Payment Table. ================================================================ When mapping insert, update and delete procs to a Entity, insure that all the three or none are mapped. Further if you have a base class and derived class in the CSDL, then you must map (ins, upd, del) sprocs to all parent and child entities in the inheritance relationship. Note that this limitation that base and derived entity methods must all must be mapped does not apply when you are mapping Read Stored Procedures.... ================================================================ You can write stored procedures SQL directly into the SSDL by creating a Function element in the SSDL and then once created, you can map this Function to a CSDL Entity directly in the designer during Function Import ================================================================ You can do Entity Splitting such that One Entity maps to multiple tables in the DB. For e.g. the Customer Entity currently derives from Contact Entity...in addition it also references the ContactPersonalInfo Entity. One can copy all properties from the ContactPersonalInfo Entity into the Customer Entity and then Delete the CustomerPersonalInfo entity, finall one needs to map the copied properties to the ContactPersonalInfo Table in Table Mapping (by adding another table (ContactPersonalInfo) to the Table Mapping... this is called Entity Splitting. Thus now when you insert a Customer record, it will automatically create SQL to insert records into the Contact, Customers and ContactPersonalInfo tables even though you have a Single Entity called Customer in the CSDL =================================================================== There is Table by Type Inheritance where another EDM Entity can derive from another EDM entity and absorb the inherted entities properties, for example in the Break Away Geek Adventures EDM, the Customer entity derives (inherits) from the Contact Entity and absorbs all the properties of Contact entity. Thus when you create a Customer Entity in Code and then call context.SaveChanges the Object Context will first create the TSQL to insert into the Contact Table followed by a TSQL to insert into the Customer table =================================================================== Then there is the Table per Hierarchy Inheritance..... where different types are created based on a condition (similar applying a condition to filter a Entity to contain filtered records)... the diference being that the filter condition populates a new Entity Type (derived from the base Entity). In the BreakAway sample the example is Lodging Entity which is a Abstract Entity and Then Resort and NonResort Entities which derive from Lodging Entity and records are filtered based on the value of the Resort Boolean field =================================================================== Then there is Table per Concrete Type Hierarchy where we create a concrete Entity for each table in the database. In the BreakAway sample there is a entity for the Reservation table and another Entity for the OldReservation table even though both the table contain the same number of fields. The OldReservation Entity can then inherit from the Reservation Entity and configure the OldReservation Entity to remove all Scalar Properties from the Entity (since it inherits the properties from Reservation and filters based on ReservationDate field) =================================================================== Complex Types (Complex Properties) Entities in EF can also contain Complex Properties (in addition to Scalar Properties) and these Complex Properties reference a ComplexType (not a EntityType) DropdownList, ListBox, RadioButtonList, CheckboxList, Bulletedlist are examples of List server controls (not data bound controls) these controls cannot use Complex properties during databinding, they need Scalar Properties. So if a Entity contains Complex properties and you need to bind those to list server controls then use projections to return Scalar properties and bind them to the control (the disadvantage is that projected collections are not tracked by the Object Context and hence cannot persist changes to the projected collections bound to controls) ObjectDataSource and EntityDataSource do account for Complex properties and one can bind entities with Complex Properties to Data Source controls and they will be tracked for changes... with no additional plumbing needed to persist changes to these collections bound to controls So DataBound controls like GridView, FormView need to use EntityDataSource or ObjectDataSource as a datasource for entities that contain Complex properties so that changes to the datasource done using the GridView can be persisted to the DB (enabling the controls for updates)....if you cannot use the EntityDataSource you need to flatten the ComplexType Properties using projections With EF Version 4 ComplexTypes are supported by the Designer and can add/remove/compose Complex Types directly using the Designer =================================================================== Conditional Mapping ... is like Table per Hierarchy Inheritance where Entities inherit from a base class and then used conditions to populate the EntitySet (called conditional Mapping). Conditional Mapping has limitations since you can only use =, is null and IS NOT NULL Conditions to do conditional mapping. If you need more operators for filtering/mapping conditionally then use QueryView(or possibly Defining Query) to create a readonly entity. QueryView are readonly by default... the EntitySet created by the QueryView is enabled for change tracking by the ObjectContext, however the ObjectContext cannot create insert/update/delete TSQL statements for these Entities when SaveChanges is called since it is QueryView. One way to get around this limitation is to map stored procedures for the insert/update/delete operations in the Designer. =================================================================== Difference between QueryView and Defining Query : QueryView is defined in the (MSL) Mapping File/section of the EDM XML, whereas the DefiningQuery is defined in the store schema (SSDL). QueryView is written using Entity SQL and is this database agnostic and can be used against any database/Data Layer. DefiningQuery is written using Database Lanaguage i.e. TSQL or PSQL thus you have more control =================================================================== Performance: Lazy loading is deferred loading done automatically. lazy loading is supported with EF version4 and is on by default. If you need to turn it off then use context.ContextOptions.lazyLoadingEnabled = false To improve Performance consider PreCompiling the ObjectQuery using the CompiledQuery.Compile method

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