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  • Where to Store ID Field In Silverlight

    - by Blake Blackwell
    I am trying to use the MVVM pattern, and I am wondering where I place an ID value. Do I create a TextBlock that has its visibility property set to collapsed? Or is there a better place to store this kind of data? Currently the command parameter is set to: CommandParameter="{Binding ElementName=Name,Path=Text}" But I'd rather it be something like: CommandParameter="{Binding ElementName=Id,Path=Text}" I'm totally up for suggestions on what the best way there is to do this, since I'm new to this pattern and presentation language. <ListBox x:Name="MyListBox" ItemsSource="{Binding MyData, Mode=TwoWay}" BorderThickness="0"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <CheckBox x:Name="Visible" IsChecked="{Binding Visible, Mode=TwoWay}" Command="{Binding ElementName=MyListBox, Path=DataContext.MyCommand}" CommandParameter="{Binding ElementName=Name,Path=Text}" /> <TextBlock Text="{Binding Name}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> EDIT: Option 1 <CheckBox x:Name="Visible" IsChecked="{Binding Visible, Mode=TwoWay}" Command="{Binding ElementName=MyListBox, Path=DataContext.MyCommand}" CommandParameter="{Binding Id}" /> This option gives me just the Id, which is useful in many situations. EDIT: Option 2 <CheckBox x:Name="Visible" IsChecked="{Binding Visible, Mode=TwoWay}" Command="{Binding ElementName=MyListBox, Path=DataContext.MyCommand}" CommandParameter="{Binding}" /> This option gives me the full model, which is even useful for my particular situation.

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  • Why does implementing ObservableCollection crash my silverlight application?

    - by Sudeep
    Hi, I have a combobox whose ItemsSource property is bound to an ObservableCollection property and its SelectedIndex property is bound to an integer property respectively. <ComboBox Name="cmbDealt" ItemsSource="{Binding Path=DealList, Mode=TwoWay}" SelectedIndex="{Binding Mode=TwoWay, Path=DealIndex}"></ComboBox> <CheckBox IsChecked="{Binding Mode=TwoWay, Path=SomeCondition}" Content="Some Condition"></CheckBox> My data structure looks like private ObservableCollection<string> m_DealList = null; private int m_DealIndex = 0; private bool m_SomeCondition = false; public ObservableCollection<string> DealList { get { if (m_DealList == null) m_DealList = new ObservableCollection<string>(); else m_DealList.Clear(); if (m_SomeCondition) { m_DealList.Add("ABC"); m_DealList.Add("DEF"); } else { m_DealList.Add("UVW"); m_DealList.Add("XYZ"); } return m_DealList; } } public int DealIndex { get { return m_DealIndex; } set { if (value != -1) { m_DealIndex = value; } } } public bool SomeCondition { get { return m_SomeCondition; } set { m_SomeCondition = value; OnPropertyChanged("DealList"); OnPropertyChanged("DealIndex"); } } Now the application loads successfully. However, when the user changes the SelectedIndex of the ComboBox to 1 from 0 and then checks the checkbox (so as to call the "DealIndex" property changed event), the application crashes. I am not sure why this could be happening. Can someone shed some light and propose a solution? TIA... Sudeep

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  • Save Dialog on top of another custom dialog is behaving strangely!

    - by Raghu
    I have a save as image feature for charts in my application. The chart control is a custom user control with custom logic in them. It also has some scaling based on size, zoom etc. However, while saving them as an image I would like to give the user the option to set the size of the image (eg: 800x600 px @ 300 DPI). To do this I have created a Form with textboxes/checkboxes etc for various settings for image. One of these TextBoxes is for the file name. The file name textbox is readonly and is accompanied with a browse button which shows a SaveFileDialog when clicked. The user clicks "Save As Image" in the main form's menu. I show the ImageExportDialog using the code below: using(ImageExportDialog dlg = new ImageExportDialog()) { if(dlg.ShowDialog() == DialogResult.OK) { //get the settings selected by the user and generate the image } } In the ImageExportDialog, the user clicks on the browse button and the SaveFileDialog is shown as follows: using(SaveFileDialog dlg = new SaveFileDialog()) { if(dlg.ShowDialog() == DialogResult.OK) { txtFileName.Text = dlg.FileName; } } Now the problem is, when the user clicks on "Save" button in the SaveFileDialog, as expected the txtFileName.Text is set, but the parent custom dialog also seems to return from the ShowDialog method and the DialogResult is the same as the one for SaveFileDialog! The control then goes on to the "get the settings selected by the user and generate the image" part of the code above. Not really sure what I am doing wrong here!

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  • Receiving generic typed <T> custom objects through remote object in Flex

    - by Aaron
    Is it possible to receive custom generic typed objects through AMF? I'm trying to integrate a flex app with an existing C# service but flex is choking on custom generic typed objects. As far as I can tell Flex doesn't even support generics, but I'd like to be able to even just read in the object and cast its members as necessary. I basically just want flex to ignore the <T>. I'm hopeful that there's a way to do this, since flex doesn't complain about typed collections (a server call returning List works fine and flex converts it to an ArrayCollection just like an un-typed List). Here's a trimmed down example of what's going on for me: The custom C# typed class public class TypeTest<T> { public T value { get; set; } public TypeTest () { } } The server method returning the typeTest public TypeTest<String> doTypeTest() { TypeTest<String> theTester = new TypeTest<String>("grrrr"); return theTester; } The corresponding flex value object: [RemoteClass(alias="API.Model.TypeTest")] public class TypeTest { private var _value:Object; public function get value():Object { return _value; } public function set value(theValue:Object):void { _value = value; } public function TypeTest() { } } and the result handler code: public function doTypeTest(result:TypeTest):void { var theString:String = result.value as String; trace(theString); } When the result handler is called I get the runtime error: TypeError: Error #1034: Type Coercion failed: cannot convert mx.utils::ObjectProxy@11a98041 to com.model.vos.TypeTest. Irritatingly if I change the result handler to take parameter of type Object it works fine. Anyone know how to make this work with the value object? I feel like i'm missing something really obvious.

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  • Rhino Mocks Partial Mock

    - by dotnet crazy kid
    I am trying to test the logic from some existing classes. It is not possible to re-factor the classes at present as they are very complex and in production. What I want to do is create a mock object and test a method that internally calls another method that is very hard to mock. So I want to just set a behaviour for the secondary method call. But when I setup the behaviour for the method, the code of the method is invoked and fails. Am I missing something or is this just not possible to test without re-factoring the class? I have tried all the different mock types (Strick,Stub,Dynamic,Partial ect.) but they all end up calling the method when I try to set up the behaviour. using System; using MbUnit.Framework; using Rhino.Mocks; namespace MMBusinessObjects.Tests { [TestFixture] public class PartialMockExampleFixture { [Test] public void Simple_Partial_Mock_Test() { const string param = "anything"; //setup mocks MockRepository mocks = new MockRepository(); var mockTestClass = mocks.StrictMock<TestClass>(); //record beahviour *** actualy call into the real method stub *** Expect.Call(mockTestClass.MethodToMock(param)).Return(true); //never get to here mocks.ReplayAll(); //this is what i want to test Assert.IsTrue(mockTestClass.MethodIWantToTest(param)); } public class TestClass { public bool MethodToMock(string param) { //some logic that is very hard to mock throw new NotImplementedException(); } public bool MethodIWantToTest(string param) { //this method calls the if( MethodToMock(param) ) { //some logic i want to test } return true; } } } }

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  • Sending URL as a parameter using javascript

    - by Prashant Singh
    I have to send a name and a link from client side to the server. I thought of using AJAX called by Javascript to do this. This is what I mean. I wished to make an ajax request to a file called abc.php with parameters :- 1. http://thumbs2.ebaystatic.com/m/m7dFgOtLUUUSpktHRspjhXw/140.jpg 2. Apple iPod touch, 3rd generation, 32GB To begin with, I encoded the URL and tried to send it. But the server says status Forbidden Any solution to this ? UPDATE :: It end up calling to http://abc.com/addToWishlist.php?rand=506075547542422&image=http://thumbs1.ebaystatic.com/m/mO64jQrMqam2jde9aKiXC9A/140.jpg&prod=Flat%20USB%20Data%20Sync%20Charging%20Charger%20Cable%20Apple%20iPhone%204G%204S%20iPod%20Touch%20Nano Javascript Code :: function addToWishlist(num) { var myurl = "addToWishlist.php"; var myurl1 = myurl; myRand = parseInt(Math.random()*999999999999999); var rand = "?rand="+myRand ; var modurl = myurl1+ rand + "&image=" + encodeURI(storeArray[num][1]) + "&prod=" + encodeURI(storeArray[num][0]); httpq2.open("GET", modurl, true); httpq2.onreadystatechange = useHttpResponseq2; httpq2.send(null); } function useHttpResponseq2() { if (httpq2.readyState == 4) { if(httpq2.status == 200) { var mytext = httpq2.responseText; document.getElementById('wish' + num).innerHTML = "Added to your wishlist."; } } } Server Code <?php include('/home/ankit/public_html/connect_db.php'); $image = $_GET['image']; $prod = $_GET['prod']; $id = $_GET['id']; echo $prod; echo $image; ?> As I mentioned, its pretty basics More Updates : On trying to send a POST request via AJAX to the server, it says :- Refused to set unsafe header "Content-length" Refused to set unsafe header "Connection"

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  • How can I increment a counter every N loops in JMeter?

    - by Dave Hunt
    I want to test concurrency, and reliably replicate an issue that JMeter brought to my attention. What I want to do is set a unique identifier (currently the time in milliseconds with a counter appended) and increment the counter between loops but not between threads. The idea being that the number of threads I have set up is the number of identical identifiers before incrementing and using another. If I had 3 threads with a loop count of 2 I want: 1. Unique ID: <current-time-in-millis>000000 2. Unique ID: <current-time-in-millis>000000 3. Unique ID: <current-time-in-millis>000000 4. Unique ID: <current-time-in-millis>000001 5. Unique ID: <current-time-in-millis>000001 6. Unique ID: <current-time-in-millis>000001 I've tried using Throughput Controllers to increment a counter, as well as several other things that seemed they should work but had no luck. This seems like something JMeter should be able to do. Is there any way to get the value of the loop count?

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  • Getting Feedburner Subscriber With CURL

    - by Eray Alakese
    I'm using FeedBurner Awareness API. XML data like this : <rsp stat="ok"> - <!-- This information is part of the FeedBurner Awareness API. If you want to hide this information, you may do so via your FeedBurner Account. --> - <feed id="9n66llmt1frfir51p0oa367ru4" uri="teknoblogo"> <entry date="2011-01-15" circulation="11" hits="18" reach="0"/> </feed> </rsp> I want to get circulation data (11) . I'm using this code: $whaturl="https://feedburner.google.com/api/awareness/1.0/GetFeedData?uri=teknoblogo"; //Initialize the Curl session $ch = curl_init(); //Set curl to return the data instead of printing it to the browser. curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); //Set the URL curl_setopt($ch, CURLOPT_URL, $whaturl); //Execute the fetch $data = curl_exec($ch); //Close the connection curl_close($ch); $xml = new SimpleXMLElement($data); $fb = $xml->feed->entry['circulation']; echo $fb; echo "OK"; But, returned data is blank. There isn't any error. Only return OK . How can i solve this ? EDIT : echo $data; returning blank, too.

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  • How to use a class's type as the type argument for an inherited collection property in C#

    - by Edelweiss Peimann
    I am trying to create a representation of various types of card that inherit from a generic card class and which all contain references to their owning decks. I tried re-declaring them, as suggested here, but it still won't convert to the specific card type. The code I currently have is as such: public class Deck<T> : List<T> where T : Card { void Shuffle() { throw new NotImplementedException("Shuffle not yet implemented."); } } public class Card { public Deck<Card> OwningDeck { get; set; } } public class FooCard : Card { public Deck<FooCard> OwningDeck { get { return (Deck<FooCard>)base.OwningDeck; } set { OwningDeck = value; } } } The compile-time error I am getting: Error 2 Cannot convert type 'Game.Cards.Deck' to 'Game.Cards.Deck' And a warning suggesting I use a new operator to specify that the hiding is intentional. Would doing so be a violation of convention? Is there a better way? My question to stackoverflow is this: Can what I am trying to do be done elegantly in the .NET type system? If so, can some examples be provided?

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  • Intercepting Xstream conversion while parsing XML

    - by Shane Bell
    Suppose I have a simple Java class like this: public class User { String firstName; String lastName; public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } } Now, suppose I want to parse the following XML: <user> <firstName>Homer</firstName> <lastName>Simpson</lastName> </user> I can do this with no problems in XStream like so: User homer = (User) xstream.fromXML(xml); Ok, all good so far, but here's my problem. Suppose I have the following XML that I want to parse: <user> <fullName>Homer Simpson</fullName> </user> How can I convert this XML into the same User object using XStream? I'd like a way to implement some kind of callback so that when XStream parses the fullName field, I can split the string in two and manually set the first name and last name fields on the user object. Is this possible? Note that I'm not asking how to split the string in two (that's the easy part), I want to know how to intercept the XML parsing so XStream doesn't try to reflectively set the fullName field on the User object (which obviously doesn't exist). I looked at the converters that XStream provides but couldn't figure out how to use it for this purpose. Any help would be appreciated.

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  • How to get pixel information inside a fragment shader?

    - by user697111
    In my fragment shader I can load a texture, then do this: uniform sampler2D tex; void main(void) { vec4 color = texture2D(tex, gl_TexCoord[0].st); gl_FragColor = color; } That sets the current pixel to color value of texture. I can modify these, etc and it works well. But a few questions. How do I tell "which" pixel I am? For example, say I want to set pixel 100,100 (x,y) to red. Everything else to black. How do I do a : "if currentSelf.Position() == (100,100); then color=red; else color=black?" ? I know how to set colors, but how do I get "my" location? Secondly, how do I get values from a neighbor pixel? I tried this: vec4 nextColor = texture2D(tex, gl_TexCoord[1].st); But not clear what it is returning? if I'm pixel 100,100; how do I get the values from 101,100 or 100,101?

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  • How can "today's date" be varied for unit testing purposes?

    - by ck
    I use VS2008 targetting .NET 2.0 Framework, and, just in case, no I can't change this :) I have a DateCalculator class. Its method GetNextExpirationDate attempts to determine the next expiration, internally using DateTime.Today as a baseline date. As I was writing unit tests, I realized that I wanted to test GetNextExpirationDate for different 'today' dates. What's the best way to do this? Here are some alternatives I've considered: Expose a property/overloaded method with argument baselineDate and only use it from the unit test. In actual client code, disregard the property/overloaded method in favour of the method that defaults baselineDate to DateTime.Today. I'm reluctant to do this as it makes the public interface of the DateCalculator class awkward. Create a protected field called baselineDate that is internally set to DateTime.Today. When testing, derive a DateCalculatorForTesting from DateCalculator and set baslineDate via the constructor. It keeps the public interface clean, but still isn't great - baselineDate was made protected and a derived class is required, both solely for testing. Use extension methods. I tried this after adding the ExtensionAttribute, then realized it wouldn't work because extension methods can't access private/protected variables. I initially thought this was really quite an elegant solution. :( I'd be interested in hearing what others think.

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  • C# StackOverflowException

    - by KSwift87
    Problem: I am trying to update a List. If a certain item's ID already exists in the List, I want to add onto that item's quantity. If not, then I want to add another item to the list. cart = (List<OrderItem>)Session["cart"]; for(int counter = cart.Count-1; counter >= 0; counter--) { if (cart[counter].productId == item.productId) { cart[counter].productQuantity += item.productQuantity; } else if (counter == 0) { cart.Add(item); } } "cart[counter]" and "item" represent an instance(s) of a custom object of mine. Currently when I finally find a matching ID, everything APPEARS as though it should work, but I get a StackOverflowException thrown in my custom object class. public int productQuantity { get { return _productQuantity; } set { productQuantity = value; } } It gets thrown right at the open-bracket of the "set". Could somebody please tell me what the heck is wrong because I've been going at this for the past 2+ hours to no avail. Thank you in advance.

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  • Segmentation fault with queue in C

    - by Trevor
    I am getting a segmentation fault with the following code after adding structs to my queue. The segmentation fault occurs when the MAX_QUEUE is set high but when I set it low (100 or 200), the error doesn't occur. It has been a while since I last programmed in C, so any help is appreciated. #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX_QUEUE 1000 struct myInfo { char data[20]; }; struct myInfo* queue; void push(struct myInfo); int queue_head = 0; int queue_size = 0; int main(int argc, char *argv[]) { queue = (struct myInfo*) malloc(sizeof(struct myInfo) * MAX_QUEUE); struct myInfo info; char buf[10]; strcpy(buf, "hello"); while (1) { strcpy(info.data, buf); push(info); } } void push(struct myInfo info) { int next_index = sizeof(struct myInfo) * ((queue_size + queue_head) % MAX_QUEUE); printf("Pushing %s to %d\n", info.data, next_index); *(queue + (next_index)) = info; queue_size++; } Output: Pushing hello to 0 Pushing hello to 20 ... Pushing hello to 7540 Pushing hello to 7560 Pushing hello to 7580 Segmentation fault

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  • When to use certain optimizations such as -fwhole-program and -fprofile-generate with several shared libraries

    - by James
    Probably a simple answer; I get quite confused with the language used in the GCC documentation for some of these flags! Anyway, I have three libraries and a programme which uses all these three. I compile each of my libraries seperately with individual (potentially) different sets of warning flags. However, I compile all three libraries with the same set of optimisation flags. I then compile my main programme linking in these three libraries with its own set of warning flags and the same optimisation flags used during the libraries' compilation. 1) Do I have to compile the libraries with optimisation flags present or can I just use these flags when compiling the final programme and linking to the libraries? If the latter, will it then optimise all or just some (presumably that which is called) of the code in these libraries? 2) I would like to use -fwhole-program -flto -fuse-linker-plugin and the linker plugin gold. At which stage do I compile with these on ... just the final compilation or do these flags need to be present during the compilation of the libraries? 3) Pretty much the same as 2) however with, -fprofile-generate -fprofile-arcs and -fprofile-use. I understand one first runs a programme with generate, and then with use. However, do I have to compile each of the libraries with generate/use etc. or just the final programme? And if it is just the last programme, when I then compeil with -fprofile-use will it also optimise the libraries functionality? Many thanks, James

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  • Using Flexigrid with an xml formatted source how do you specify how the xml is formatted?

    - by stormist
    I have my columns set as follows: colModel : [ {display: 'column1', name : 'column1', width : 200, sortable : true, align: 'center'}, {display: 'column2', name : 'column2', width : 100, sortable : true, align: 'left'}, {display: 'column3', name : 'column3', width : 100, sortable : true, align: 'left'}, {display: 'column4', name : 'column4', width : 300, sortable : true, align: 'left'}, ], I set my data source to a url that returns xml. The xml is like this: <?xml version="1.0"?> <items_list> <item> <column1>BlahBlah</column1> <column2>BlahBlah</column2> <column3>BlahBlah</column3> <column4>BlahBlah</column4> </item> <item> <column1>BlahBlah</column1> <column2>BlahBlah</column2> <column3>BlahBlah</column3> <column4>BlahBlah</column4> </item> </items_list> How can I bind the grid to the xml datasource, it doesn't appear to recognize it as it is?

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  • Bulk insert of component collection in Hibernate?

    - by edbras
    I have the mapping as listed below. When I update a detached Categories item (that doesn't contain any Hibernate class as it comes from a dto converter) I notice that Hibernate will first delete ALL employer wages instances (the collection link) and then insert ALL employer wage entries ONE-BY-ONE :(... I understand that it has to delete and then insert all entries as it was completely detached. BUT, what I don't understand, why is Hibernate NOT inserting all the entries through bulk-insert?.. That is: inserting all the employer wage entries all in one SQL statement ? How can I tell Hibernate to use bulk-insert? (if possible). I tried playing with the following value but didn't see any difference: hibernate.jdbc.batch_size=30 My mapping snippet: <class name="com.sample.CategoriesDefault" table="dec_cats" > <id name="id" column="id" type="string" length="40" access="property"> <generator class="assigned" /> </id> <component name="incomeInfoMember" class="com.sample.IncomeInfoDefault"> <property name="hasWage" type="boolean" column="inMemWage"/> ... <component name="wage" class="com.sample.impl.WageDefault"> <property name="hasEmployerWage" type="boolean" column="inMemEmpWage"/> ... <set name="employerWages" cascade="all-delete-orphan" lazy="false"> <key column="idCats" not-null="true" /> <one-to-many entity-name="mIWaEmp"/> </set> </component> </component> </class>

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  • What's the best way to select max over multiple fields in SQL?

    - by allyourcode
    The I kind of want to do is select max(f1, f2, f3). I know this doesn't work, but I think what I want should be pretty clear (see update 1). I was thinking of doing select max(concat(f1, '--', f2 ...)), but this has various disadvantages. In particular, doing concat will probably slow things down. What's the best way to get what I want? update 1: The answers I've gotten so far aren't what I'm after. max works over a set of records, but it compares them using only one value; I want max to consider several values, just like the way order by can consider several values. update 2: Suppose I have the following table: id class_name order_by1 order_by_2 1 a 0 0 2 a 0 1 3 b 1 0 4 b 0 9 I want a query that will group the records by class_name. Then, within each "class", select the record that would come first if you ordered by order_by1 ascending then order_by2 ascending. The result set would consist of records 2 and 3. In my magical query language, it would look something like this: select max(* order by order_by1 ASC, order_by2 ASC) from table group by class_name

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  • Modelling deterministic and nondeterministic data separately

    - by Superstringcheese
    I'm working with the Microsoft ADO.NET Entity Framework for a game project. Following the advice of other posters on SO, I'm considering modelling deterministic and nondeterministic data separately. The idea for this came from a discussion on multiplayer games, but it seemed to make sense in a single-player scenario as well. Deterministic (things that aren't going to change during gameplay) Attributes (Strength, Agility, etc.) and their descriptions Skills and their descriptions and requirements Races, Factions, Equipment, etc. Base Attribute/Skill/Equipment loadouts for monsters Nondeterministic (things that will change a lot during gameplay) Beings' current AttributeModifers (Potion of Might = +10 Strength), current health and mana, etc. Player inventory, cash, experience, level Player quests states Player FactionRelationships ...and so on. My deterministic model would serve as a set of constants. My nondeterministic model would provide my on-the-fly operable data and would be serialized to a savegame file to maintain game state between play sessions. The data store will be an embedded SQL Compact database. So I might want to create relations between my Attributes table (deterministic model) and my BeingAttributeModifiers table (nondeterministic model), but how do I set that up across models? Det model/db Nondet model/db ____________ ________________________ |Attributes | |PlayerAttributeModifiers| |------------| |------------------------| |Id | |Id | |Name | |AttributeId | |Description | |SourceId | ------------ |Value | ------------------------ Should I use two separate models (edmx) that transact with a single database containing both deterministic-type and nondeterministic-type tables? Or should/can I use two separate databases in one model? Or two models each with their own database? With distinct models/dbs it seems like this will get really complicated and I'll end up fighting EF a lot, rolling my own transaction code, and generally losing out on a lot of the advantages of the framework. I know these are vague questions, I'm just looking for a sanity check before I forge ahead any further.

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  • Is it safe to use random Unicode for complex delimiter sequences in strings?

    - by ccomet
    Question: In terms of program stability and ensuring that the system will actually operate, how safe is it to use chars like ¦, § or ‡ for complex delimiter sequences in strings? Can I reliable believe that I won't run into any issues in a program reading these incorrectly? I am working in a system, using C# code, in which I have to store a fairly complex set of information within a single string. The readability of this string is only necessary on the computer side, end-users should only ever see the information after it has been parsed by the appropriate methods. Because some of the data in these strings will be collections of variable size, I use different delimiters to identify what parts of the string correspond to a certain tier of organization. There are enough cases that the standard sets of ;, |, and similar ilk have been exhausted. I considered two-char delimiters, like ;# or ;|, but I felt that it would be very inefficient. There probably isn't that large of a performance difference in storing with one char versus two chars, but when I have the option of picking the smaller option, it just feels wrong to pick the larger one. So finally, I considered using the set of characters like the double dagger and section. They only take up one char, and they are definitely not going to show up in the actual text that I'll be storing, so they won't be confused for anything. But character encoding is finicky. While the visibility to the end user is meaningless (since they, in fact, won't see it), I became recently concerned about how the programs in the system will read it. The string is stored in one database, while a separate program is responsible for both encoding and decoding the string into different object types for the rest of the application to work with. And if something is expected to be written one way, is possibly written another, then maybe the whole system will fail and I can't really let that happen. So is it safe to use these kind of chars for background delimiters?

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  • Dependency Properties, change notification and setting values in the constructor

    - by stefan.at.wpf
    Hello, I have a clas with 3 dependency properties A,B,C. The values of these properties are set by the constructor and every time one of the properties A, B or C changes, the method recalculate() is called. Now during execution of the constructor these method is called 3 times, because the 3 properties A, B, C are changed. Hoewever this isn't necessary as the method recalculate() can't do anything really useful without all 3 properties set. So what's the best way for property change notification but circumventing this change notification in the constructor? I thought about adding the property changed notification in the constructor, but then each object of the DPChangeSample class would always add more and more change notifications. Thanks for any hint! class DPChangeSample : DependencyObject { public static DependencyProperty AProperty = DependencyProperty.Register("A", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged)); public static DependencyProperty BProperty = DependencyProperty.Register("B", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged)); public static DependencyProperty CProperty = DependencyProperty.Register("C", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged)); private static void propertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { ((DPChangeSample)d).recalculate(); } private void recalculate() { // Using A, B, C do some cpu intensive caluclations } public DPChangeSample(int a, int b, int c) { SetValue(AProperty, a); SetValue(BProperty, b); SetValue(CProperty, c); } }

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  • What is the most efficient/elegant way to parse a flat table into a tree?

    - by Tomalak
    Assume you have a flat table that stores an ordered tree hierarchy: Id Name ParentId Order 1 'Node 1' 0 10 2 'Node 1.1' 1 10 3 'Node 2' 0 20 4 'Node 1.1.1' 2 10 5 'Node 2.1' 3 10 6 'Node 1.2' 1 20 What minimalistic approach would you use to output that to HTML (or text, for that matter) as a correctly ordered, correctly intended tree? Assume further you only have basic data structures (arrays and hashmaps), no fancy objects with parent/children references, no ORM, no framework, just your two hands. The table is represented as a result set, which can be accessed randomly. Pseudo code or plain English is okay, this is purely a conceptional question. Bonus question: Is there a fundamentally better way to store a tree structure like this in a RDBMS? EDITS AND ADDITIONS To answer one commenter's (Mark Bessey's) question: A root node is not necessary, because it is never going to be displayed anyway. ParentId = 0 is the convention to express "these are top level". The Order column defines how nodes with the same parent are going to be sorted. The "result set" I spoke of can be pictured as an array of hashmaps (to stay in that terminology). For my example was meant to be already there. Some answers go the extra mile and construct it first, but thats okay. The tree can be arbitrarily deep. Each node can have N children. I did not exactly have a "millions of entries" tree in mind, though. Don't mistake my choice of node naming ('Node 1.1.1') for something to rely on. The nodes could equally well be called 'Frank' or 'Bob', no naming structure is implied, this was merely to make it readable. I have posted my own solution so you guys can pull it to pieces.

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  • copy rows before updating them to preserve archive in Postgres

    - by punkish
    I am experimenting with creating a table that keeps a version of every row. The idea is to be able to query for how the rows were at any point in time even if the query has JOINs. Consider a system where the primary resource is books, that is, books are queried for, and author info comes along for the ride CREATE TABLE authors ( author_id INTEGER NOT NULL, version INTEGER NOT NULL CHECK (version > 0), author_name TEXT, is_active BOOLEAN DEFAULT '1', modified_on TIMESTAMP DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (author_id, version) ) INSERT INTO authors (author_id, version, author_name) VALUES (1, 1, 'John'), (2, 1, 'Jack'), (3, 1, 'Ernest'); I would like to be able to update the above like so UPDATE authors SET author_name = 'Jack K' WHERE author_id = 1; and end up with 2, 1, Jack, t, 2012-03-29 21:35:00 2, 2, Jack K, t, 2012-03-29 21:37:40 which I can then query with SELECT author_name, modified_on FROM authors WHERE author_id = 2 AND modified_on < '2012-03-29 21:37:00' ORDER BY version DESC LIMIT 1; to get 2, 1, Jack, t, 2012-03-29 21:35:00 Something like the following doesn't really work CREATE OR REPLACE FUNCTION archive_authors() RETURNS TRIGGER AS $archive_author$ BEGIN IF (TG_OP = 'UPDATE') THEN -- The following fails because author_id,version PK already exists INSERT INTO authors (author_id, version, author_name) VALUES (OLD.author_id, OLD.version, OLD.author_name); UPDATE authors SET version = OLD.version + 1 WHERE author_id = OLD.author_id AND version = OLD.version; RETURN NEW; END IF; RETURN NULL; -- result is ignored since this is an AFTER trigger END; $archive_author$ LANGUAGE plpgsql; CREATE TRIGGER archive_author AFTER UPDATE OR DELETE ON authors FOR EACH ROW EXECUTE PROCEDURE archive_authors(); How can I achieve the above? Or, is there a better way to accomplish this? Ideally, I would prefer to not create a shadow table to store the archived rows.

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  • Logging exceptions to database in NServiceBus

    - by IGoor
    If an exception occurs in my MessageHandler I want to write the exception details to my database. How do I do this? Obviously, I cant just catch the exception, write to database, and rethrow it since NSB rollbacks all changes. (IsTransactional is set to true) I tried adding logging functionality in a seperate handler, which I caledl using SendLocal if an exception occured, but this does not work: public void Handle(MessageItem message) { try { DoWork(); } catch(Exception exc) { Bus.SendLocal(new ExceptionMessage(exc.Message)); throw; } } I also tried using Log4Net with a custom appender, but this also rolled back. Configure.With() .Log4Net<DatabaseAppender>(a => a.Log = "Log") appender: public class DatabaseAppender : log4net.Appender.AppenderSkeleton { public string Log { get; set; } protected override void Append(log4net.Core.LoggingEvent loggingEvent) { if (loggingEvent.ExceptionObject != null) WriteToDatabase(loggingEvent.ExceptionObject); } } Is there anyway to log unhandled exceptions in the messagehandler when IsTransactional is true? Thanks in advance.

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  • Errors when creating a custom Querable object with MVC and Subsonic pagedlist

    - by minus4
    hiya, i have the following code but when i try and create a new IQuerable i get an error that the interface cannot be implemented, if i take away the new i get a not implemented exception, have had to jump back and work on some old ASP classic sites for past month and for the life of me i can not wake my brain up into C# mode. Could you please have a look at below and give me some clues on where i'm going wrong: The code is to create a list of priceItems, but instead of a categoryID (int) i am going to be showing the name as string. public ActionResult ViewPriceItems(int? page) { var crm = 0; page = GetPage(page); // try and create items2 IQueryable<ViewPriceItemsModel> items2 = new IQueryable<ViewPriceItemsModel>(); // the data to be paged,but unmodified var olditems = PriceItem.All().OrderBy(x => x.PriceItemID); foreach (var item in olditems) { // set category as the name not the ID for easier reading items2.Concat(new [] {new ViewPriceItemsModel {ID = item.PriceItemID, Name = item.PriceItem_Name, Category = PriceCategory.SingleOrDefault( x => x.PriceCategoryID == item.PriceItem_PriceCategory_ID).PriceCategory_Name, Display = item.PriceItems_DisplayMethod}}); } crm = olditems.Count() / MaxResultsPerPage; ViewData["numtpages"] = crm; ViewData["curtpage"] = page + 1; // return a paged result set return View(new PagedList<ViewPriceItemsModel>(items2, page ?? 0, MaxResultsPerPage)); } many thanks

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