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• Self updating app, wont overwrite existing app, using Android packagemanager?

  - by LokiSinclair

  I know there are plenty of questions about this on here, but I've tried everything (but the correct 'thing', obviously!) and nothing seems to shine any light on the problem I'm having. I've written an app (for a customer), which is designed to be hosted on their own server. The app references a simple text file with the latest version code in it and checks it against it's own version. If it's out of date it goes off and downloads the update. Everything is working as intended up to this point. I use the: Intent i = new Intent(Intent.ACTION_VIEW); i.setDataAndType(Uri.fromFile(outputFile), "application/vnd.android.package-archive"); i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(i); ...code to start the install process of the newly downloaded .apk file. And that all starts as I would expect. I click on "Install" - when I'm prompted to confirm the overwriting of the current app, with the new. It starts, and then displays: App not installed. And existing package by the same name with a conflicting signature is already installed. Now I'm aware that Android can't have multiple applications sharing the same package name, which is fine, but nothing comes up in LogCat and I can only assume that the OS is annoyed at me attempting to 'update' my app, even though I'm going through all the correct channels and using the inbuilt package manager to do it for me! Can anyone tell me what the OS is moaning about? I'm not attempting to install two apps side by side, I want it to update it, which it starts to do, and then gets really confused. Is it something to do with me using the same keystore for signing the packages? I highly doubt it as I've used the same keystores previously to handle updates to games and the like, but I just can't figure out what it's complaining about. Hopefully someone out there has had this issue and solved it, and can point me in the right direction. I'm flying a bit blind with the limited information it's giving me :( Cheers.

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• Checking if an int is prime more efficiently

  - by SipSop

  I recently was part of a small java programming competition at my school. My partner and I have just finished our first pure oop class and most of the questions were out of our league so we settled on this one (and I am paraphrasing somewhat): "given an input integer n return the next int that is prime and its reverse is also prime for example if n = 18 your program should print 31" because 31 and 13 are both prime. Your .class file would then have a test case of all the possible numbers from 1-2,000,000,000 passed to it and it had to return the correct answer within 10 seconds to be considered valid. We found a solution but with larger test cases it would take longer than 10 seconds. I am fairly certain there is a way to move the range of looping from n,..2,000,000,000 down as the likely hood of needing to loop that far when n is a low number is small, but either way we broke the loop when a number is prime under both conditions is found. At first we were looping from 2,..n no matter how large it was then i remembered the rule about only looping to the square root of n. Any suggestions on how to make my program more efficient? I have had no classes dealing with complexity analysis of algorithms. Here is our attempt. public class P3 { public static void main(String[] args){ long loop = 2000000000; long n = Integer.parseInt(args[0]); for(long i = n; i<loop; i++) { String s = i +""; String r = ""; for(int j = s.length()-1; j>=0; j--) r = r + s.charAt(j); if(prime(i) && prime(Long.parseLong(r))) { System.out.println(i); break; } } System.out.println("#"); } public static boolean prime(long p){ for(int i = 2; i<(int)Math.sqrt(p); i++) { if(p%i==0) return false; } return true; } } ps sorry if i did the formatting for code wrong this is my first time posting here. Also the output had to have a '#' after each line thats what the line after the loop is about Thanks for any help you guys offer!!!

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• How come my South migrations doesn't work for Django?

  - by TIMEX

  First, I create my database. create database mydb; I add "south" to installed Apps. Then, I go to this tutorial: http://south.aeracode.org/docs/tutorial/part1.html The tutorial tells me to do this: $ py manage.py schemamigration wall --initial >>> Created 0001_initial.py. You can now apply this migration with: ./manage.py migrate wall Great, now I migrate. $ py manage.py migrate wall But it gives me this error... django.db.utils.DatabaseError: (1146, "Table 'fable.south_migrationhistory' doesn't exist") So I use Google (which never works. hence my 870 questions asked on Stackoverflow), and I get this page: http://groups.google.com/group/south-users/browse_thread/thread/d4c83f821dd2ca1c Alright, so I follow that instructions >> Drop database mydb; >> Create database mydb; $ rm -rf ./wall/migrations $ py manage.py syncdb But when I run syncdb, Django creates a bunch of tables. Yes, it creates the south_migrationhistory table, but it also creates my app's tables. Synced: > django.contrib.admin > django.contrib.auth > django.contrib.contenttypes > django.contrib.sessions > django.contrib.sites > django.contrib.messages > south > fable.notification > pagination > timezones > fable.wall > mediasync > staticfiles > debug_toolbar Not synced (use migrations): - (use ./manage.py migrate to migrate these) Cool....now it tells me to migrate these. So, I do this: $ py manage.py migrate wall The app 'wall' does not appear to use migrations. Alright, so fine. I'll add wall to initial migrations. $ py manage.py schemamigration wall --initial Then I migrate: $ py manage.py migrate wall You know what? It gives me this BS: _mysql_exceptions.OperationalError: (1050, "Table 'wall_content' already exists") Sorry, this is really pissing me off. Can someone help ? thanks. How do I get South to work and sync correctly with everything?

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• Add Access-Control-Allow-Origin to header in PHP

  - by SANDeveloper

  I am trying to workaround CORS restriction on a WebGL application. I have a Web Service which resolves URL and returns images. Since this web service is not CORS enabled, I can't use the returned images as textures. I was planning to: Write a PHP script to handle image requests Image requests would be sent through the query string as a url parameter The PHP Script will: Call the web service with the query string url Fetch the image response (web service returns a content-type:image response) Add the CORS header (Add Access-Control-Allow-Origin) to the response Send the response to the browser I tried to implement this using a variety of techniques including CURL, HTTPResponse, plain var_dump etc. but got stuck at some point in each. So I have 2 questions: Is the approach good enough? Considering the approach is good enough: I made the most progress with CURL. I could get the image header and data with: $ch = curl_init(); $url = $_GET["url"]; curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_HEADER, true); curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type:image/jpeg')); //Execute request $response = curl_exec($ch); //get the default response headers $headers = curl_getinfo($ch); //close connection curl_close($ch); But this doesn't actually change set the response content-type to image/jpeg. It dumps the header + response into a new response of content-type text/html and display the header and the image BLOB data in the browser. How do I get it to send the response in the format I want? Managed to get it working: $ch = curl_init(); $url = $_GET["url"]; curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_HEADER, false); //Execute request $response = curl_exec($ch); //get the default response headers $headers = curl_getinfo($ch); curl_setopt($ch, CURLOPT_HTTPHEADER, $headers); header('Content-Type: image/jpeg'); header("Access-Control-Allow-Origin: *"); // header("Expires: Sat, 26 Jul 2017 05:00:00 GMT"); //close connection curl_close($ch); flush();

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• auto complete asp.net

  - by lodun

  Why my autocomplete ajax script does not work: This is my WebService.cs: using System; using System.Data; using System.Web; using System.Collections; using System.Web.Services; using System.Web.Services.Protocols; using System.ComponentModel; using System.Data.SqlClient; using System.Collections.Generic; using System.Configuration; using System.Web.Script.Services; [ScriptService] [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. public class WebService : System.Web.Services.WebService { public WebService () { //Uncomment the following line if using designed components //InitializeComponent(); } [WebMethod] public string[] GetCountryInfo(string prefixText, int count) { string sql = "Select * from questions Where username like @prefixText"; SqlDataAdapter da = new SqlDataAdapter(sql,"estudent_piooConnectionString"); da.SelectCommand.Parameters.Add("@prefixText", SqlDbType.VarChar, 50).Value = prefixText + "%"; DataTable dt = new DataTable(); da.Fill(dt); string[] items = new string[dt.Rows.Count]; int i = 1; foreach (DataRow dr in dt.Rows) { items.SetValue(dr["username"].ToString(),i); i++; } return items; } } my css: /*AutoComplete flyout */ .autocomplete_completionListElement { margin : 0px!important; background-color : inherit; color : windowtext; border : buttonshadow; border-width : 1px; border-style : solid; cursor : 'default'; overflow : auto; height : 200px; text-align : left; list-style-type : none;padding:0px; } /* AutoComplete highlighted item */ .autocomplete_highlightedListItem { background-color: #ffff99; color: black; padding: 1px; } /* AutoComplete item */ .autocomplete_listItem { background-color : window; color : windowtext; padding : 1px; } and textbox: <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox> <cc1:AutoCompleteExtender ID="AutoCompleteExtender1" CompletionListCssClass="autocomplete_completionListElement" CompletionListItemCssClass="autocomplete_listItem" CompletionSetCount="20" CompletionInterval="1000" DelimiterCharacters=";,:" CompletionListHighlightedItemCssClass="autocomplete_highlightedList MinimumPrefixLength="1" ServiceMethod="GetCountryInfo" ShowOnlyCurrentWordInCompletionListItem="true" TargetControlID="TextBox2" ServicePath="WebService.asmx" runat="server"></cc1:AutoCompleteExtender>

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• SQLAlchemy unsupported type error - and table design issues?

  - by Az

  Hi there, back again with some more SQLAlchemy shenanigans. Let me step through this. My table is now set up as so: engine = create_engine('sqlite:///:memory:', echo=False) metadata = MetaData() students_table = Table('studs', metadata, Column('sid', Integer, primary_key=True), Column('name', String), Column('preferences', Integer), Column('allocated_rank', Integer), Column('allocated_project', Integer) ) metadata.create_all(engine) mapper(Student, students_table) Fairly simple, and for the most part I've been enjoying the ability to query almost any bit of information I want provided I avoid the error cases below. The class it is mapped from is: class Student(object): def __init__(self, sid, name): self.sid = sid self.name = name self.preferences = collections.defaultdict(set) self.allocated_project = None self.allocated_rank = 0 def __repr__(self): return str(self) def __str__(self): return "%s %s" %(self.sid, self.name) Explanation: preferences is basically a set of all the projects the student would prefer to be assigned. When the allocation algorithm kicks in, a student's allocated_project emerges from this preference set. Now if I try to do this: for student in students.itervalues(): session.add(student) session.commit() It throws two errors, one for the allocated_project column (seen below) and a similar error for the preferences column: sqlalchemy.exc.InterfaceError: (InterfaceError) Error binding parameter 4 - probably unsupported type. u'INSERT INTO studs (sid, name, allocated_rank, allocated_project) VALUES (?, ?, ?, ?, ?, ?, ?)' [1101, 'Muffett,M.', 1, 888 Human-spider relationships (Supervisor id: 123)] If I go back into my code I find that, when I'm copying the preferences from the given text files, it actually refers to the Project class which is mapped to a dictionary, using the unique project id's (pid) as keys. Thus, as I iterate through each student via their rank and to the preferences set, it adds not a project id, but the reference to the project id from the projects dictionary. students[sid].preferences[int(rank)].add(projects[int(pid)]) Now this is very useful to me since I can find out all I want to about a student's preferred projects without having to run another check to pull up information about the project id. The form you see in the error has the object print information passed as: return "%s %s (Supervisor id: %s)" %(self.proj_id, self.proj_name, self.proj_sup) My questions are: I'm trying to store an object in a database field aren't I? Would the correct way then, be copying the project information (project id, name, etc) into its own table, referenced by the unique project id? That way I can just have the project id field for one of the student tables just be an integer id and when I need more information, just join the tables? So and so forth for other tables? If the above makes sense, then how does one maintain the relationship with a column of information in one table which is a key index on another table? Does this boil down into a database design problem? Are there any other elegant ways of accomplishing this? Apologies if this is a very long-winded question. It's rather crucial for me to solve this, so I've tried to explain as much as I can, whilst attempting to show that I'm trying (key word here sadly) to understand what could be going wrong.

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• How to avoid repetition when working with primitive types?

  - by I82Much

  I have the need to perform algorithms on various primitive types; the algorithm is essentially the same with the exception of which type the variables are. So for instance, /** * Determine if <code>value</code> is the bitwise OR of elements of <code>validValues</code> array. * For instance, our valid choices are 0001, 0010, and 1000. * We are given a value of 1001. This is valid because it can be made from * ORing together 0001 and 1000. * On the other hand, if we are given a value of 1111, this is invalid because * you cannot turn on the second bit from left by ORing together those 3 * valid values. */ public static boolean isValid(long value, long[] validValues) { for (long validOption : validValues) { value &= ~validOption; } return value != 0; } public static boolean isValid(int value, int[] validValues) { for (int validOption : validValues) { value &= ~validOption; } return value != 0; } How can I avoid this repetition? I know there's no way to genericize primitive arrays, so my hands seem tied. I have instances of primitive arrays and not boxed arrays of say Number objects, so I do not want to go that route either. I know there are a lot of questions about primitives with respect to arrays, autoboxing, etc., but I haven't seen it formulated in quite this way, and I haven't seen a decisive answer on how to interact with these arrays. I suppose I could do something like: public static<E extends Number> boolean isValid(E value, List<E> numbers) { long theValue = value.longValue(); for (Number validOption : numbers) { theValue &= ~validOption.longValue(); } return theValue != 0; } and then public static boolean isValid(long value, long[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } public static boolean isValid(int value, int[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } Is that really much better though? Any thoughts in this matter would be appreciated.

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• UITableViewCell outlets not set during bundle load (possibly very elementary question)

  - by Jan Zich

  What are the most common reasons for an outlet (a class property) not being set during a bundle load? I'm sorry; most likely I'm not using the correct terms. It's my first steps with iPhone OS development and Objective-C, so please bear with me. Here is more details. Basically, I'm trying to create a table view based form with a fixed number of static rows. I followed this example: http://developer.apple.com/iphone/library/documentation/userexperience/conceptual/TableView_iPhone/TableViewCells/TableViewCells.html Scroll down to The Technique for Static Row Content please. I have one nib file with one table view, three table cells and all connections set as in the example. The problem is that the corresponding cell properties in my controller are never initialised. I get an exception in cellForRowAtIndexPath complaining that the returned cell is nil: UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath. Here are the relevant parts from the implementation of the controller: @synthesize cellA; @synthesize cellB; @synthesize cellC; - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 3; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { switch (indexPath.row) { case 0: return cellA; break; case 1: return cellB; break; case 2: return cellC; break; default: return nil; } } And here is the interface part: @interface AssociatePhoneViewController : UITableViewController { UITableViewCell *cellA; UITableViewCell *cellB; UITableViewCell *cellB; } @property (nonatomic, retain) IBOutlet UITableViewCell *cellA; @property (nonatomic, retain) IBOutlet UITableViewCell *cellB; @property (nonatomic, retain) IBOutlet UITableViewCell *cellC; @end This must be possibly one of the the most embarrassing questions on StackOverflow. It looks like the most basic example code. Is is possible that the cells are not instantiated with the nib file? I have them on the same level before the tabula view in the nib file. I tried to move them after the table view, but it did not make any difference. Are table cells in some way special? Do I need to set some flag or some property on them in the nib file? I was under the impression that all classes (views, windows, controllers …) listed in a nib file are simply instantiated (and linked using the provided connections). Could it possibly be some memory issue? The cell properties in my controller are not defined in any special way.

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• WPF performance for large number of elements on the screen

  - by Mark

  Im currently trying to create a Scene in WPF where I have around 250 controls on my screen and the user can Pan and Zoom in and out of these controls using the mouse. I have run the WPF Performance Suite tools on the application when there are a large number of these controls on the screen (i.e. when the user has zoomed right out) the FPS drops down to around 15 which is not very good. Here is the basic outline of the XAML: <Window> <Window.Resources> <ControlTemplate x:Key="LandTemplate" TargetType="{x:Type local:LandControl}"> <Canvas> <Path Fill="White" Stretch="Fill" Stroke="Black" StrokeThickness="1" Width="55.5" Height="74.687" Data="M0.5,0.5 L55,0.5 L55,74.187 L0.5,74.187 z"/> <Canvas x:Name="DetailLevelCanvas" Width="24.5" Height="21" Canvas.Left="15.306" Canvas.Top="23.972"> <TextBlock Width="21" Height="14" Text="712" TextWrapping="Wrap" Foreground="Black"/> <TextBlock Width="17.5" Height="7" Canvas.Left="7" Canvas.Top="14" Text="614m2" TextWrapping="Wrap" FontSize="5.333" Foreground="Black"/> </Canvas> </Canvas> </ControlTemplate> </Window.Resources> ... <local:LandControl Width="55.5" Height="74.552" Canvas.Top="xxx" Template=" {StaticResource LandTemplate}" RenderTransformOrigin="0.5,0.5" Canvas.Left="xxx"> <local:LandControl Width="55.5" Height="74.552" Canvas.Top="xxx" Template=" {StaticResource LandTemplate}" RenderTransformOrigin="0.5,0.5" Canvas.Left="xxx"> <local:LandControl Width="55.5" Height="74.552" Canvas.Top="xxx" Template=" {StaticResource LandTemplate}" RenderTransformOrigin="0.5,0.5" Canvas.Left="xxx"> <local:LandControl Width="55.5" Height="74.552" Canvas.Top="xxx" Template=" {StaticResource LandTemplate}" RenderTransformOrigin="0.5,0.5" Canvas.Left="xxx"> ... and so on... </Window> Ive tried to minimise the details in the control template and I even did a massive find and replace of the controls to just put their raw elements inline instead of using a template, but with no noticeable performance improvements. I have seen other SO questions about this and people say to do custom drawing, but I dont really see how that make sense when you have to zoom and pan like I do. If anyone can help out here, that would be great! Mark

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• How to count the length (number of lines) of a csv file in Rails?

  - by Mathias

  Hello, I have a form (Rails) which allows me to load a .csv file using the file_field. In the view: <% form_for(:upcsv, :html => {:multipart => true}) do |f| %> <table> <tr> <td><%= f.label("File:") %></td> <td><%= f.file_field(:filename) %></td> </tr> </table> <%= f.submit("Submit") %> <% end %> Clicking Submit redirects me to another page (create.html.erb). The file was loaded fine, and I was able to read the contents just fine in this second page. I am trying to show the number of lines in the .csv file in this second page. My controller (semi-pseudocode): class UpcsvController < ApplicationController def index end def create file = params[:upcsv][:filename] ... #params[:upcsv][:file_length] = file.length # Show number of lines in the file #params[:upcsv][:file_length] = file.size ... end end Both file.length and file.size returns '91' when my file only contains 7 lines. From the Rails documentation that I read, once the Submit button is clicked, Rails creates a temp file of the uploaded file, and the params[:upcsv][:filename] contains the contents of the temp/uploaded file and not the path to the file. And I don't know how to extract the number of lines in my original file. What is the correct way to get the number of lines in the file? My create.html.erb: <table> <tr> <td>File length:</td> <td><%= params[:upcsv][:file_length] %></td> </tr> </table> I'm really new at Rails (just started last week), so please bear with my stupid questions. Thank you!

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• Chrome extension: sendMessage doesn't work

  - by user3334776

  I've already read the documentation from Google on 'message passing' a few times and have probably looked at over 10 other questions with the same problem and already tried quiet a few variations of most of their "solutions" and of what I have below... This is black magic, right? Either way, here it goes. Manifest File: { "manifest_version" : 2, "name" : "Message Test", "version" : "1.0", "browser_action": { "default_popup": "popup.html" }, "background": { "scripts": ["background.js"] }, "content_scripts": [ { "matches" : ["<all_urls>"], "js": ["message-test.js"] } ] } I'm aware extensions aren't suppose to use inline JS, but I'm leaving this in so the original question can be left as it was since I still can't get the message to send from the background page, When I switch from the popup to the background, I removed the appropriate lines from the manifest.json popup.html file: <html> <head> <script> chrome.tabs.query({active: true, currentWindow: true}, function(tabs) { chrome.tabs.sendMessage(tabs[0].id, {greeting: "hello", theMessage: "Why isn\'t this working?"}, function(response) { console.log(response.farewell); }); }); </script> </head> <body> </body> </html> OR background.js file: chrome.tabs.query({active: true, currentWindow: true}, function(tabs) { chrome.tabs.sendMessage(tabs[0].id, {greeting: "hello", theMessage: "Why isn\'t this working?"}, function(response) { console.log(response.farewell); }); }); message-test.js file: var Mymessage; chrome.runtime.onMessage.addListener(function(message, sender, sendResponse) { if (message.greeting == "hello"){ Mymessage = message.theMessage; alert(Mymessage); } else{ sendResponse({}); } }); No alert(Mymessage) goes off. I'm also trying to execute this after pressing a button from a popup and having a window at a specified url, but that's a later issue. The other files can be found here except with the background.js content wrapped in an addEventListener("click"....: http://pastebin.com/KhqxLx5y AND http://pastebin.com/JaGcp6tj

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• Access violation when running native C++ application that uses a /clr built DLL

  - by doobop

  I'm reorganzing a legacy mixed (managed and unmanaged DLLs) application so that the main application segment is unmanaged MFC and that will call a C++ DLL compiled with /clr flag that will bridge the communication between the managed (C# DLLs) and unmanaged code. Unfortuantely, my changed have resulted in an Access violation that occurs before the application InitInstance() is called. This makes it very difficult to debug. The only information I get is the following stack trace. > 64006108() ntdll.dll!_ZwCreateMutant@16() + 0xc bytes kernel32.dll!_CreateMutexW@12() + 0x7a bytes So, here are some sceanrios I've tried. - Turned on Exceptions-Win32 Exceptions-c0000005 Access Violation to break when Thrown. Still the most detail I get is from the above stack trace. I've tried the application with F10, but it fails before any breakpoints are hit and fails with the above stack trace. - I've stubbed out the bridge DLL so that it only has one method that returns a bool and that method is coded to just return false (no C# code called). bool DllPassthrough::IsFailed() { return false; } If the stubbed out DLL is compiled with the /clr flag, the application fails. If it is compiled without the /clr flag, the application runs. - I've created a stub MFC application using the Visual Studio wizard for multidocument applications and call DllPassthrough::IsFailed(). This succeeds even with the /clr flag used to compile the DLL. - I've tried doing a manual LoadLibrary on winmm.lib as outlined in the following note Access violation when using c++/cli. The application still fails. So, my questions are how to solve the problem? Any hints, strategies, or previous incidents. And, failing that, how can I get more information on what code segment or library is causing the access exception? If I try more involved workarounds like doing LoadLibrary calls, I'd like to narrow it to the failing libraries. Thanks. BTW, we are using Visual Studio 2008 and the project is being built against the .NET 2.0 framework for the managed sections.

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• Collision point of 2 curves in a 3d-room

  - by Frank

  Hello, i am programming a small game for quite some time. We started coding a small FPS-Shooter inside of a project at school to get a bit experience using directX. I dont know why, but i couldnt stop the project and started programming at home aswell. At the moment i am trying to create some small AI. Of cause thats definatlly not easy, but thats my personal goal anyways. The topic could prolly fill multiple books hehe. I've got the walking part of my bots done so far. They walk along a scriped path. I am not working on the "aiming" of the bots. While programming that i hit on some math problem i couldnt solve yet. I hope of your input on this to help me get further. Concepts, ideas and everything else are highly appreciated. Problem: Calculate the position (D3DXVECTOR3) where the curve of the projectile (depends on gravity, speed), hit the curved of the enemys walking path (depends on speed). We assume that the enemy walks in a constant line. Known variables: float projectilSpeed = 2000 m/s //speed of the projectile per second float gravitation = 9.81 m/s^2 //of cause the gravity lol D3DXVECTOR3 targetPosition //position of the target stored in a vector (x,y,z) D3DXVECTOR3 projectilePosition //position of the projectile D3DXVECTOR3 targetSpeed //stores the change of the targets position in the last second Variabledefinition ProjectilePosition at time of collision = ProjectilePos_t TargetPosition at time of collision = TargetPos_t ProjectilePosition at time 0, now = ProjectilePos_0 TargetPosition at time 0, now = TargetPos_0 Time to impact = t Aim-angle = theta My try: Found a formular to calculate "drop" (Drop of the projectile based on the gravity) on Wikipedia: float drop = 0.5f * gravity * t * t The speed of the projectile has a horizontal and a vertical part.. Found a formular for that on wikipedia aswell: ProjectilVelocity.x = projectilSpeed * cos(theta) ProjectilVelocity.y = projectilSpeed * sin(theta) So i would assume this is true for the projectile curve: ProjectilePos_t.x = ProjectilePos_0.x + ProjectileSpeed * t ProjectilePos_t.y = ProjectilePos_0.y + ProjectileSpeed * t + 0.5f * gravity * t * t ProjectilePos_t.z = ProjectilePos_0.z + ProjectileSpeed * t The target walk with a constant speed, so we can determine his curve by this: TargetPos_t = TargetPos_0 + TargetSpeed * D3DXVECTOR3(t, t, t) Now i dont know how to continue. I have to solve it somehow to get a hold on the time to impact somehow. As a basic formular i could use: float time = distanz / projectileSpeed But that wouldnt be truly correct as it would assume a linear "Trajectory". We just find this behaivor when using a rocket. I hope i was able to explain the problem as much as possible. If there are questions left, feel free to ask me! Greets from germany, Frank

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• Virtual member call in a constructor when assigning value to property

  - by comecme

  I have an Abstract class and a Derived class. The abstract class defines an abstract property named Message. In the derived class, the property is implemented by overriding the abstract property. The constructor of the derived class takes a string argument and assigns it to its Message property. In Resharper, this assignment leads to a warning "Virtual member call in constructor". The AbstractClass has this definition: public abstract class AbstractClass { public abstract string Message { get; set; } protected AbstractClass() { } public abstract void PrintMessage(); } And the DerivedClass is as follows: using System; public class DerivedClass : AbstractClass { private string _message; public override string Message { get { return _message; } set { _message = value; } } public DerivedClass(string message) { Message = message; // Warning: Virtual member call in a constructor } public DerivedClass() : this("Default DerivedClass message") {} public override void PrintMessage() { Console.WriteLine("DerivedClass PrintMessage(): " + Message); } } I did find some other questions about this warning, but in those situations there is an actual call to a method. For instance, in this question, the answer by Matt Howels contains some sample code. I'll repeat it here for easy reference. class Parent { public Parent() { DoSomething(); } protected virtual void DoSomething() {}; } class Child : Parent { private string foo; public Child() { foo = "HELLO"; } protected override void DoSomething() { Console.WriteLine(foo.ToLower()); } } Matt doesn't describe on what error the warning would appear, but I'm assuming it will be on the call to DoSomething in the Parent constructor. In this example, I understand what is meant by a virtual member being called. The member call occurs in the base class, in which only a virtual method exists. In my situation however, I don't see why assigning a value to Message would be calling a virtual member. Both the call to and the implementation of the Message property are defined in the derived class. Although I can get rid of the error by making my Derived Class sealed, I would like to understand why this situation is resulting in the warning.

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• How can this PHP/FQL code be modified to increase the performance and usability?

  - by Kaoukkos

  I try to get some insights from the pages I am administrator on Facebook. What my code does, it gets the IDs of the pages I want to work with through mySQL. I did not include that part though.After this, I get the page_id, name and fan_count of each of those facebook IDs and are saved in fancounts[]. Using the IDs ( pages[] ) I get two messages max from each page. There may be no messages, there may be 1 or 2 messages max. Possibly I will increase it later. messages[] holds the messages of each page. I have two problems with it. It has a very slow performance I can't find a way to echo the data like this: ID - Name of the page - Fan Count Here goes the first message Here goes the second one //here is a break ID - Name of the page 2 - Fan Count Here goes the first message of page 2 Here goes the second one of page 2 My questions are, how can the code be modified to increase performance and show the data as above? I read about fql.multiquery. Can it be used here? Please provide me with code examples. Thank you $pages = array(); // I get the IDs I want to work with $pagesIds = implode(',', $pages); // fancounts[] holds the page_id, name and fan_count of the Ids I work with $fancounts = array(); $pagesFanCounts = $facebook->api("/fql", array( "q" => "SELECT page_id, name, fan_count FROM page WHERE page_id IN ({$pagesIds})" )); foreach ($pagesFanCounts['data'] as $page){ $fancounts[] = $page['page_id']."-".$page['name']."-".$page['fan_count']; } //messages[] holds from 0 to 2 messages from each of the above pages $messages = array(); foreach( $pages as $id) { $getMessages = $facebook->api("/fql", array( "q" => "SELECT message FROM stream WHERE source_id = '$id' LIMIT 2" )); $messages[] = $getMessages['data']; } // this is how I print them now but it does not give me the best output. ( thanks goes to Mark for providing me this code ) $count = min(count($fancounts),count($messages)); for($i=0; $i<$count; ++$i) { echo $fancounts[$i],'<br>'; foreach($messages[$i] as $msg) { echo $msg['message'],'<br>'; } }

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• log4net initialisation

  - by Ruben Bartelink

  I've looked hard for duplicates but have to ask the following, no matter how basic it may seem, to get it clear once and for all! In a fresh Console app using log4net version 1.2.10.0 on VS28KSP1 on 64 bit W7, I have the following code:- using log4net; using log4net.Config; namespace ConsoleApplication1 { class Program { static readonly ILog _log = LogManager.GetLogger(typeof(Program)); static void Main(string[] args) { _log.Info("Ran"); } } } In my app.config, I have: <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" /> </configSections> <log4net> <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender"> <file value="Program.log" /> <lockingModel type="log4net.Appender.FileAppender+MinimalLock" /> <appendToFile value="true" /> <rollingStyle value="Size" /> <maxSizeRollBackups value="10" /> <maximumFileSize value="1MB" /> <staticLogFileName value="true" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="[%username] %date [%thread] %-5level %logger [%property{NDC}] - %message%newline" /> </layout> </appender> <root> <level value="DEBUG" /> <appender-ref ref="RollingFileAppender" /> </root> </log4net> </configuration> This doesnt write anything, unless I either add an attribute: [ assembly:XmlConfigurator ] Or explicitly initialise it in Main(): _log.Info("This will not go to the log"); XmlConfigurator.Configure(); _log.Info("Ran"); This raises the following questions: I'm almost certain I've seen it working somewhere on some version of log4net without the addition of the assembly attribute or call in Main. Can someone assure me I'm not imagining that? Can someone please point me to where in the doc it explicitly states that both the config section and the initialisation hook are required - hopefully with an explanation of when this changed, if it did? I can easily imagine why this might be the policy -- having the initialisation step explicit to avoid surprises etc., it's just that I seem to recall this not always being the case... (And normally I have the config in a separate file, which generally takes configsections out of the picture)

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• How can I refactor this JavaScript code to avoid making functions in a loop?

  - by Bungle

  I wrote the following code for a project that I'm working on: var clicky_tracking = [ ['related-searches', 'Related Searches'], ['related-stories', 'Related Stories'], ['more-videos', 'More Videos'], ['web-headlines', 'Publication'] ]; for (var x = 0, length_x = clicky_tracking.length; x < length_x; x++) { links = document.getElementById(clicky_tracking[x][0]) .getElementsByTagName('a'); for (var y = 0, length_y = links.length; y < length_y; y++) { links[y].onclick = (function(name, url) { return function() { clicky.log(url, name, 'outbound'); }; }(clicky_tracking[x][1], links[y].href)); } } What I'm trying to do is: define a two-dimensional array, with each instance the inner arrays containing two elements: an id attribute value (e.g., "related-searches") and a corresponding description (e.g., "Related Searches"); for each of the inner arrays, find the element in the document with the corresponding id attribute, and then gather a collection of all <a> elements (hyperlinks) within it; loop through that collection and attach an onclick handler to each hyperlink, which should call clicky.log, passing in as parameters the description that corresponds to the id (e.g., "Related Searches" for the id "related-searches") and the value of the href attribute for the <a> element that was clicked. Hopefully that wasn't thoroughly confusing! The code may be more self-explanatory than that. I believe that what I've implemented here is a closure, but JSLint complains: http://img.skitch.com/20100526-k1trfr6tpj64iamm8r4jf5rbru.png So, my questions are: How can I refactor this code to make JSLint agreeable? Or, better yet, is there a best-practices way to do this that I'm missing, regardless of what JSLint thinks? Should I rely on event delegation instead? That is, attaching onclick event handlers to the document elements with the id attributes in my arrays, and then looking at event.target? I've done that once before and understand the theory, but I'm very hazy on the details, and would appreciate some guidance on what that would look like - assuming this is a viable approach. Thanks very much for any help!

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• MVC pattern implementation. What is the n-relation between its components

  - by Srodriguez

  Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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• MVC pattern implementation. What is the n-relation between its components

  - by Srodriguez

  Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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• Function Point Analysis -- a seriously overestimating technique?

  - by kizzx2

  I know questions about FPA has been asked numerous times before, but this time I'm taking a more analytical angle at it, backed up with data. 1. First, some data This question is based on a tutorial. He had a "Sample Count" section where he demonstrated it step by step. You can see some screenshots of his sample application here. In the end, he calculated the unadjusted FP to be 99. There is another article on InformIT with industry data on typical hour/FP. It ranges from 2 hours/FP to 27.4 hours/FP. Let's try to stick with 2 for the moment (since SO readers are probably the more efficient crowd :p). 2. Reality check!? Now just check out the screenshots again. Do a little math here 99 * 2 = 198 hours 198 hours / 40 hours per week = 5 weeks Seriously? That sample application is going to take 5 weeks to implement? Is it just my feeling that it wouldn't take any decent programmer longer than one week (I"m not even saying weekend) to have it completed? Now let's try estimating the cost of the project. We'll use New York's minimum wage at the moment (Wikipedia), which is $7.25 198 * 7.25 = $1435.5 From what I could see from the screenshots, this application is a small excel-improvement app. I could have bought MS Office Pro for 200 bucks which gives me greater interoperability (.xls files) and flexibility (spreadsheets). (For the record, that same Web site has another article discussing productivity. It seems like they typically use 4.2 hours/FP, which gives us even more shocking stats: 99 * 4.2 = 415 hours = 10 weeks = almost 3 whopping months! 415 hours * $7.25 = $3000 zomg (That's even assuming that all our poor coders get the minimum wage!) 3. Am I missing something here? Right now, I could come up with several possible explanation: FPA is really only suited for bigger projects (1000+ FPs) so it becomes extremely inaccurate at smaller scale. The hours/FP metric fluctuates abruptly from team to team, project to project. For a small project like this, we could have used something like 0.5 hour/FP or something. (Now this kind of makes the whole estimation thing pointless, unless my firm does the same type of projects for several years with the same team, not really common.) From my experience with several software metrics, Function Point is really not a lightweight metric. If the hour/FP thing fluctuates so much, then what's the point, maybe I could have gone with User Story Points which is a lot faster to get and arguably almost as uncertain. What would be the FP experts' answers to this?

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• Contact form problem - I do receive messages, but no contents (blank page).

  - by nitbuntu

  I have a contact form on site which used to work, but since last few months has stopped working properly. This could have been due to some coding error that I can't figure out. What happens is that I receive the messages sent, but they are completely blank, with no contents at all. What could be the problems? I'm attaching first the front-end page, and then the back-end. Sample of contact.php the front-end code:- <div id="content"> <h2 class="newitemsxl">Contact Us</h2> <div id="contactcontent"> <form method="post" action="contactus.php"> Name:<br /> <input type="text" name="Name" /><br /> Email:<br /> <input type="text" name="replyemail" /><br /> Your message:<br /> <textarea name="comments" cols="40" rows="4"></textarea><br /><br /> <?php require("ClassMathGuard.php"); MathGuard::insertQuestion(); ?><br /> <input type="submit" name="submit" value="Send" /> * Refresh browser for a different question. :-) </form> </div> </div> Sample of contactus.php (backend code):- <?php /* first we need to require our MathGuard class */ require ("ClassMathGuard.php"); /* this condition checks the user input. Don't change the condition, just the body within the curly braces */ if (MathGuard :: checkResult($_REQUEST['mathguard_answer'], $_REQUEST['mathguard_code'])) { $mailto="[email protected]"; $pcount=0; $gcount=0; $subject = "A Stylish Goods Enquiry"; $from="[email protected]"; echo ("Great, you're message has been sent !"); //insert your code that will be executed when user enters the correct answer } else { echo ("Sorry, wrong answer, please go back and try again !"); //insert your code which tells the user he is spamming your website } while (list($key,$val)=each($HTTP_POST_VARS)) { $pstr = $pstr."$key : $val \n "; ++$pcount; } while (list($key,$val)=each($HTTP_GET_VARS)) { $gstr = $gstr."$key : $val \n "; ++$gcount; } if ($pcount > $gcount) { $comments=$pstr; mail($mailto,$subject,$comments,"From:".$from); } else { $comments=$gstr; mail($mailto,$subject,$comments,"From:".$from); } ?>

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• java instanceof not finding method

  - by Razvan N

  I have a problem with java instanceof. I have a class called Employee and several others that extend this one, for example - Manager. I also created another class,EmployeeStockPlan, where I wanted to test if instanceof is finding which object I am using. But when I am calling a method from the new class, I have this error: The method grantStock(Manager) is undefined for the type Loader. Sorry, I am somehow new to some thing in java, I hope I am not asking dumb questions. The Employee class: package com.example.domain; public class Employee { private int empId; private String name; private String ssn; private double salary; public Employee(int empId, String name, String ssn, double salary) { // constructor // method; this.empId = empId; this.name = name; this.ssn = ssn; this.salary = salary; } public void setName(String newName) { if (newName != null) { this.name = newName; } } public void raiseSalary(double increase) { this.salary += increase; } public String getName() { return name; } public double getSalary() { return salary; } public String getDetails() { return "Employee id: " + empId + "\n" + "Employee name: " + name; } } The Manager class: package com.example.domain; public class Manager extends Employee { private String deptName; public Manager(int empId, String name, String ssn, double salary, String dept) { super(empId, name, ssn, salary); this.deptName = dept; } public String getDeptName() { return deptName; } public String getDetails() { return super.getDetails() + "\n" + "Department: " + deptName; } } The EmployeeStockPlan class: package com.example.domain; public class EmployeeStockPlan { public void grantStock(Employee e) { // nothing calculated, just simulating; System.out.println("This is an employee!"); if (e instanceof Manager) { // process Manager stock grant System.out.println("This is a manager!"); } else { // error - instance of Engineer? System.out.println("Not an engineer!"); } return; } } The main class: EmployeeStockPlan esp = new EmployeeStockPlan(); Manager m = new Manager (12421, "Manager1", "111-4254-521", 2430, "Marketing1"); grantStock(m);

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• Silverlight MVVM MEF ViewInjection

  - by silverfighter

  Hi all, since my title is buzzword compliant I hope I will get lots of answers to my question or any pointers to the right direction. OK what I usually do is have a ViewModel which contains a list of ViewModels itself. public class MasterViewModel { public ObservableCollection<DetailViewModel> DetailViewModels { get; set; } public DetailViewModel Detail { get; set; } } <ItemsControl ItemsSource="{Binding DetailViewModels}"> <ItemsControl> <ItemsPanelTemplate> <StackPanel /> </ItemsPanelTemplate> </ItemsControl> <ItemsControl.ItemTemplate> <DataTemplate> <views:DetailsView /> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> With this in mind I will now come to my questions. I read a lot of good things about MEF and also saw the dashboard sample of Glenn Block but this was not helping me enough. What I want to do is sidbar (like the windows sidebar). Sidebar = StackPanel ListItems = Gadget ButI want it MVVM style OK I have something like a contract IGadget I implemented an custom Export. [ExportGadget(GadgetType = GadgetTypes.News)] I have my NewsGadgetView.xaml (which implements IGadget) and imports the NewsGadgetViewModel and also makes itself available as ExportGadget. so far so good. With this I can create a set of gadgets. Then I have my SidbarView.xaml which imports a sidebarViewModel. and now I get lost... I thought of something like a GadgetFactory which uses PartCreator to create my Gadgets. but this would sit in my SidebarView.xaml But I want to have control over my Gadgets to add and remove them from my sidebar. So I thought about something like an ObserveableCollection... Which I bind to The GadgetHost is basicaly Grid which will dynamicaly load the Gadget.... So how would I create my sidebar containing different gadgets without knowing which Gadgets are available and have a ViewModel for the sidebar as well as for each gadget?... Thanks for any help....

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• GHC.Generics and Type Families

  - by jberryman

  This is a question related to my module here, and is simplified a bit. It's also related to this previous question, in which I oversimplified my problem and didn't get the answer I was looking for. I hope this isn't too specific, and please change the title if you can think if a better one. Background My module uses a concurrent chan, split into a read side and write side. I use a special class with an associated type synonym to support polymorphic channel "joins": {-# LANGUAGE TypeFamilies #-} class Sources s where type Joined s newJoinedChan :: IO (s, Messages (Joined s)) -- NOT EXPORTED --output and input sides of channel: data Messages a -- NOT EXPORTED data Mailbox a instance Sources (Mailbox a) where type Joined (Mailbox a) = a newJoinedChan = undefined instance (Sources a, Sources b)=> Sources (a,b) where type Joined (a,b) = (Joined a, Joined b) newJoinedChan = undefined -- and so on for tuples of 3,4,5... The code above allows us to do this kind of thing: example = do (mb , msgsA) <- newJoinedChan ((mb1, mb2), msgsB) <- newJoinedChan --say that: msgsA, msgsB :: Messages (Int,Int) --and: mb :: Mailbox (Int,Int) -- mb1,mb2 :: Mailbox Int We have a recursive action called a Behavior that we can run on the messages we pull out of the "read" end of the channel: newtype Behavior a = Behavior (a -> IO (Behavior a)) runBehaviorOn :: Behavior a -> Messages a -> IO () -- NOT EXPORTED This would allow us to run a Behavior (Int,Int) on either of msgsA or msgsB, where in the second case both Ints in the tuple it receives actually came through separate Mailboxes. This is all tied together for the user in the exposed spawn function spawn :: (Sources s) => Behavior (Joined s) -> IO s ...which calls newJoinedChan and runBehaviorOn, and returns the input Sources. What I'd like to do I'd like users to be able to create a Behavior of arbitrary product type (not just tuples) , so for instance we could run a Behavior (Pair Int Int) on the example Messages above. I'd like to do this with GHC.Generics while still having a polymorphic Sources, but can't manage to make it work. spawn :: (Sources s, Generic (Joined s), Rep (Joined s) ~ ??) => Behavior (Joined s) -> IO s The parts of the above example that are actually exposed in the API are the fst of the newJoinedChan action, and Behaviors, so an acceptable solution can modify one or all of runBehaviorOn or the snd of newJoinedChan. I'll also be extending the API above to support sums (not implemented yet) like Behavior (Either a b) so I hoped GHC.Generics would work for me. Questions Is there a way I can extend the API above to support arbitrary Generic a=> Behavior a? If not using GHC's Generics, are there other ways I can get the API I want with minimal end-user pain (i.e. they just have to add a deriving clause to their type)?

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• Hide public method used to help test a .NET assembly

  - by ChrisW

  I have a .NET assembly, to be released. Its release build includes: A public, documented API of methods which people are supposed to use A public but undocumented API of other methods, which exist only in order to help test the assembly, and which people are not supposed to use The assembly to be released is a custom control, not an application. To regression-test it, I run it in a testing framework/application, which uses (in addition to the public/documented API) some advanced/undocumented methods which are exported from the control. For the public methods which I don't want people to use, I excluded them from the documentation using the <exclude> tag (supported by the Sandcastle Help File Builder), and the [EditorBrowsable] attribute, for example like this: /// <summary> /// Gets a <see cref="IEditorTransaction"/> instance, which helps /// to combine several DOM edits into a single transaction, which /// can be undone and redone as if they were a single, atomic operation. /// </summary> /// <returns>A <see cref="IEditorTransaction"/> instance.</returns> IEditorTransaction createEditorTransaction(); /// <exclude/> [EditorBrowsable(EditorBrowsableState.Never)] void debugDumpBlocks(TextWriter output); This successfully removes the method from the API documentation, and from Intellisense. However, if in a sample application program I right-click on an instance of the interface to see its definition in the metadata, I can still see the method, and the [EditorBrowsable] attribute as well, for example: // Summary: // Gets a ModelText.ModelDom.Nodes.IEditorTransaction instance, which helps // to combine several DOM edits into a single transaction, which can be undone // and redone as if they were a single, atomic operation. // // Returns: // A ModelText.ModelDom.Nodes.IEditorTransaction instance. IEditorTransaction createEditorTransaction(); // [EditorBrowsable(EditorBrowsableState.Never)] void debugDumpBlocks(TextWriter output); Questions: Is there a way to hide a public method, even from the meta data? If not then instead, for this scenario, would you recommend making the methods internal and using the InternalsVisibleTo attribute? Or would you recommend some other way, and if so what and why? Thank you.

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