&lt;del&gt;You could use something like compilr.com, however, it requires a paid account (as of June 2013) to create projects but people can view it anonymously. It&#39;s pretty neat.&lt;/del&gt; (*compilr closed down*)


&lt;del&gt;Example:
http://compilr.com/cravecode/test-share/main.cs&lt;/del&gt;

&lt;del&gt;UPDATE 1&lt;/del&gt;
------

&lt;del&gt;I&#39;d also checkout [coderun.com/ide][3]&lt;/del&gt; (no longer available)

UPDATE 2
--

Check [dotnetfiddle.net][4] which has Context menu as well (pointed out by @wulfbane).


UPDATE 3 (2017-03-19)
--
Keeping answer updated, I now use:

 - https://csharppad.com
 - http://rextester.com **(has a really neat collaboration feature)**
 - https://dotnetfiddle.net

You may also want to check [Ideone][5] (has no context menu)

  [3]: http://www.coderun.com/ide/
  [4]: http://dotnetfiddle.net
  [5]: http://ideone.com

When diffing files, I prefer to use `git diff --color-words`. Is there a way to make this the default format for diffs when using `git add --patch` or `git add --interactive`?

How to use --color-words with git add --patch?

I have created a `C# console based project`. In that project i have some variables like `companyName`, `companyType` which are Strings. 

    companyName=&quot;someCompanyName&quot;;
    companyType=&quot;someCompanyType&quot;;

I need to create a config file and read values from it, and then initialize the variables `companyName`, `companyType` in the code. 

1. How can i create a config file (or equivalent) ?
2. How can i read from the config file ?

Adding and reading from a Config file

Similar to [jsfiddle][1], is there an asp.net fiddle website for us to share asp.net code fiddles? It&#39;ll greatly help asp.net developers. the current way to post asp.net code on SO is not so reader friendly. I hope there&#39;s something out there to make this easier. If there isn&#39;t anything like that (as i did some search but can&#39;t find one). Is this even something technically possible to be developed since c# is not a late binding language.


  [1]: http://jsfiddle.net

is there an asp.net fiddle?

<p>Similar to <a href="http://jsfiddle.net" target="_blank" rel="noopener noreferrer">jsfiddle</a>, is there an asp.net fiddle website for us to share asp.net code fiddles? It'll greatly help asp.net developers. the current way to post asp.net code on SO is not so reader friendly. I hope there's something out there to make this easier. If there isn't anything like that (as i did some search but can't find one). Is this even something technically possible to be developed since c# is not a late binding language.</p>


I&#39;m using Linq/EF4.1 to pull some results from a database and would like to limit the results to the (X) most recent results.  Where X is a number set by the user.

Is there a way to do this?

I&#39;m currently passing them back as a `List` if this will help with limiting the result set.  While I can limit this by looping until I hit X I&#39;d just assume not pass the extra data around.

Just in case it is relevant...
C# MVC3 project running from a SQL Server database.

Limit Number of Results being returned in a List from Linq

I have a web project in my solution file that is &quot;unavailable&quot; when I open the solution. When I right-click on the web project and reload the project, I get the following error:

`
The Web Application Project mycompany.myapp.mywebproject is configured to use IIS. The Web Server &#39;http://localhost/MyWebApp could not be found.
`

I have not manually set up virtual directories for this web application. 

Per colleagues, Visual Studio should prompt me to create virtual directories but I am not getting prompted. 

I installed VS2010 before installing IIS on my dev machine. 

Here is my development machine setup:

 - Windows 7 Enterprise
 - Service Pack 1
 - 64 bit OS
 - Visual Studio 2010 Enterprise Service pack 1
 - IIS version 7.5




The Web Application Project [...] is configured to use IIS. The Web server [...] could not be found. 

I&#39;m trying to capture the screen and then convert it to a Base64 string. This is my code:

    Rectangle bounds = Screen.GetBounds(Point.Empty);
    Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height);

    using (Graphics g = Graphics.FromImage(bitmap))
    {
       g.CopyFromScreen(Point.Empty, Point.Empty, bounds.Size);
    }

    // Convert the image to byte[]
    System.IO.MemoryStream stream = new System.IO.MemoryStream();
    bitmap.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);
    byte[] imageBytes = stream.ToArray();

    // Write the bytes (as a string) to the textbox
    richTextBox1.Text = System.Text.Encoding.UTF8.GetString(imageBytes);

    // Convert byte[] to Base64 String
    string base64String = Convert.ToBase64String(imageBytes);

Using a richTextBox to debug, it shows: 

&gt; BM6�~

So for some reason the bytes aren&#39;t correct which causes the base64String to become null. Any idea what I&#39;m doing wrong? Thanks.

How to convert Bitmap to a Base64 string?

I am having a problem returning an output parameter from a Sql Server stored procedure into a C# variable. I have read the other posts concerning this, not only here but on other sites, and I cannot get it to work. Here is what I currently have. Currently I am just trying to print the value that comes back. The following code returns a null value. What I an trying to return is the primary key. I have tried using `@@IDENTITY` and `SCOPE_INDENTITY()` (i.e. `SET @NewId = SCOPE_IDENTITY()`). 

Stored Procedure:

    CREATE PROCEDURE usp_InsertContract
        @ContractNumber varchar(7),

        @NewId int OUTPUT
    AS
    BEGIN

        INSERT into [dbo].[Contracts] (ContractNumber)
            VALUES (@ContractNumber)

        Select @NewId = Id From [dbo].[Contracts] where ContractNumber = @ContractNumber
    END


Opening the database:
    
    pvConnectionString = &quot;Server = Desktop-PC\\SQLEXPRESS; Database = PVDatabase; User ID = sa;
        PASSWORD = *******; Trusted_Connection = True;&quot;;

    try
    {
        pvConnection = new SqlConnection(pvConnectionString);
        pvConnection.Open();
    }
    catch (Exception e)
    {
        databaseError = true;
    }
    
Executing the command:

    pvCommand = new SqlCommand(&quot;usp_InsertContract&quot;, pvConnection);

    pvCommand.Transaction = pvTransaction;
    pvCommand.CommandType = CommandType.StoredProcedure;    

    pvCommand.Parameters.Clear();
    pvCommand.Parameters.Add(new SqlParameter(&quot;@ContractNumber&quot;, contractNumber));
                 
    SqlParameter pvNewId = new SqlParameter();
    pvNewId.ParameterName = &quot;@NewId&quot;;
    pvNewId.DbType = DbType.Int32;
    pvNewId.Direction = ParameterDirection.Output;
    pvCommand.Parameters.Add(pvNewId);

    try
    {
        sqlRows = pvCommand.ExecuteNonQuery();

        if (sqlRows &gt; 0)
            Debug.Print(&quot;New Id Inserted =  &quot;, 
                pvCommand.Parameters[&quot;@NewId&quot;].Value.ToString()); 
        }
        catch (Exception e)
        {
            Debug.Print(&quot;Insert Exception Type: {0}&quot;, e.GetType());
            Debug.Print(&quot;  Message: {0}&quot;, e.Message);
        }
    }

Using stored procedure output parameters in C#

I am aware that this is a very basic question, but an interviewer asked me in a very trick way and I was helpless :(

I know only material or theoretical definition for an interface and also implemented it in many projects I worked on. But I really don&#39;t understand why and how is this useful.

I also don&#39;t understand one thing in interface. i.e for example, we use 

`conn.Dispose();` in finally block. But I don&#39;t see that class is implementing or inheriting `IDisposable` interface (`SqlConnection`) class I mean. I am wondering how I can just call the method name. Also in the same thing, I am not understanding how Dispose method works as because, we need to implement the function body with our own implementation for all interface methods. So how Interfaces are accepted or named as contracts? These questions kept on rolling in my mind till now and frankly I never saw any good thread that would explain my questions in a way that I can understand.

MSDN as usual looks very scary and no single line is clear there (*Folks, kindly excuse who are into high level development, I strongly feel that any code or article should reach the mind of anyone who see it, hence like many others say, MSDN is not of use*).

The interviewer said:

He has 5 methods and he is happy to implement it in the class directly, but if you have to go for Abstract class or interface, which one you choose and why ? I did answered him all the stuffs that I read in various blog saying advantage and disadvantage of both abstract class and interface, but he is not convinced, he is trying to understand &quot;Why Interface&quot; in general. &quot;Why abstract class&quot; in general even if I can implement the same methods only one time and not gona change it.

I see no where in net, I could get an article that would explain me clearly about interfaces and its functioning. I am one of those many programmers, who still dont know about interfaces (I know theoretical and methods I used) but not satisfied that I understood it clearly.

What is the difference between an interface and a class, and why I should use an interface when I can implement the methods directly in the class?

I&#39;m trying to select all the rows out of a database using entity framework for manipulation before they&#39;re sent to the form

    var ptx = [modelname].[tablename]();
    ptx.[tablename].Select(????)

what goes in the ????

Select All Rows Using Entity Framework

I recently upgraded from Visual Studio 2010 to the Visual Studio 2012 RC. The installer also installs IIS 8 Express which Visual Studio now uses as the default web server.

IIS 8 is blocking my WEB API requests that use PUT AND DELETE verbs. IIS returns a 405 error, `The requested resource does not support http method &#39;PUT&#39;`.

I know people have issues with this in the past and there are several messages about it on Stack Overflow. With IIS 7 Express the solution was to uninstall WebDav. Unfortunately I don&#39;t see any way to do that with IIS 8. 

I&#39;ve tried editing out the WebDav sections from applicationhost.config but that hasn&#39;t helped. For example I removed `&lt;add name=&quot;WebDAVModule&quot; image=&quot;%IIS_BIN%\webdav.dll&quot; /&gt;` from the config file.

I&#39;ve spent far too long on this. There must be a simple way to enable PUT and DELETE? 

ASP.NET Web API - PUT &amp; DELETE Verbs Not Allowed - IIS 8

I would like to know what, why or when it is better to choose cshtml and what, why or when it is better to choose aspx technologies? What are these two technologies intended for?

Thank you,

What, why or when it is better to choose cshtml vs aspx?

Hi why  `using (var sw = new StreamWriter(ms))` returns `Cannot access a closed Stream` `exception`. `Memory Stream` is on top of this code. 


    using (var ms = new MemoryStream())
    {
        using (var sw = new StreamWriter(ms))
        {                 
            sw.WriteLine(&quot;data&quot;);
            sw.WriteLine(&quot;data 2&quot;);
            ms.Position = 0;
            using (var sr = new StreamReader(ms))
            {
                Console.WriteLine(sr.ReadToEnd());                        
            }
        } //error here
    }

What the best way to fix it ?
Thanks 

MemoryStream - Cannot access a closed Stream

I have the following piece of config in my App.config file:

    &lt;add key=&quot;ConnectionString&quot; 
         value=&quot;INITIAL CATALOG=myDatabase;DATA SOURCE=myServer;User ID=myUser;Password=!&amp;myPass99;&quot;/&gt;

The above connection string is rejected by Visual Studio intellisense. It says entity `myPass99` not defined. The problem is caused by the &amp; in the password. 

How do I escape it?

Escape &amp; in App.config

I have some number of generic lists in my code, that have tens or hundreds elements.
Sometimes I need to refill this lists with other objects, so question is: what will be faster, to call `Clear()` method or creating a `new List&lt;T&gt;()`?

Which is faster: clear collection or instantiate new

So I have a web project, and I&#39;m trying to get the root directory of the website using the c# method `Directory.GetCurrentDirectory()`.  I don&#39;t want to be using a static path as the file locations will be changing in the future.  This method is running in my imageProcess.aspx.cs file, but where I thought it would return:

    C:\Users\tcbl\documents\visual studio 2010\Projects\ModelMonitoring\ModelMonitoring\imageProcess.aspx.cs

I&#39;m instead getting:
    
    C:\Program Files\Common Files\Microsoft Shared\DevServer\10.0\

Can anyone explain why this is happening and what a possible solution might be? Thanks a lot.

Getting current directory in .NET web application

I want to store words in a dictionary in following way:

I can get word code by word: `dict[&quot;SomeWord&quot;]` -&gt; `123` and get word by word code: `dict[123]` -&gt; `&quot;SomeWord&quot;`

Is it real? Of course one way to do it is two dictionaries: `Dictionary&lt;string,int&gt;` and `Dictionary&lt;int,string&gt;` but is there another way?


Two-way / bidirectional Dictionary in C#?

I recently learned ASP.NET MVC (I love it). I&#39;m working with a company that uses dependency injection to load a Repository instance in each request, and I&#39;m familiar with using that repository.

But now I&#39;m writing a couple of MVC applications of my own. I don&#39;t fully understand the hows and whys of the repository my company uses, and I&#39;m trying to decide the best approach to implement data access.

I am using C# and Entity Framework (with all the latest versions).

I see three general approaches for handling data access.

1. Regular DB context within a using statement each time I access data. This is simple and it works okay. However, if two locations need to read the same data within one request, the data must be read twice. (With a single repository per request, the same instance would be used in both places and I understand the second read would simply return the data from the first read.)

2. A typical [repository pattern](http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/implementing-the-repository-and-unit-of-work-patterns-in-an-asp-net-mvc-application). For reasons I don&#39;t understand, this typical pattern involves creating a wrapper class for every table used from the database. That seems wrong to me. In fact, since they are implemented also as interfaces, I&#39;d technically be creating two wrapper classes for each table. EF creates tables for me. I don&#39;t believe this approach makes sense.

3. There is also a [generic repository pattern](http://www.tugberkugurlu.com/archive/generic-repository-pattern-entity-framework-asp-net-mvc-and-unit-testing-triangle) where a single repository class is created to serve all entity objects. This makes much more sense to me. But does it make sense to others? Is the link above the best approach?

I&#39;d love to get some input from others on this topic. Are you writing your own repository, using one of those above, or doing something different altogether. Please share.





Best Repository Pattern for ASP.NET MVC

I am using the .Net MVC4 Web API to (hopefully) implement a RESTful api.  I need to pass in a few parameters to the system and have it perform some action, then return a list of objects as the results.  Specifically I am passing in two dates and returning records that fall between them.  I&#39;m also keeping track of the records returned so that subsequent calls do not get reprocessed in the system.

I&#39;ve considered a few approaches:

1.  Serializing the params into one single JSON string and picking it apart in the API.
http://forums.asp.net/t/1807316.aspx/1

2.  Pass the params in the query string.  
https://stackoverflow.com/questions/2640560/what-is-best-way-to-pass-multiple-query-parameters-to-a-restful-api

3.  Defining the params in the route:
api/controller/date1/date2

4.  Using a POST that inherently lets me pass an object with params.

5.  Researching ODATA since the Web API (currently) supports it.  I haven&#39;t done much with this yet so I&#39;m not very familiar with it.

It seems that proper REST practices indicate when data is pulled, you should use a GET.  However, GET should also be nullipotent (produces no side-effects), and I wonder if my specific implementation violates that since I mark records in the API system, hence I am producing side-effects.

It also led me to the question of supporting variable parameters.  If the input parameter list changes, it would be tedious to have to re-define your route for Choice 3 if that happens a lot.  And what might happen if the parameters are defined at run-time...

In any case, for my specific implementation, which choice (if any) seems best?

How should I pass multiple parameters to an ASP.Net Web API GET?

I have just created an ASP.NET MVC 4 project and used Visual Studio 2012 RC to create a Controller and Razor Views for `Index` and `Create` Actions.

When I came to run the application, and browsed to the `Create` view, the following error was shown:

&gt; Compiler Error Message: CS0103: The name &#39;Scripts&#39; does not exist in
&gt; the current context

The problem is the following code which was added automatically to the bottom of the View:

    @section Scripts {
    	@Scripts.Render(&quot;~/bundles/jqueryval&quot;)
    }

Why does Scripts not exist?

I looked at the base Web Page class in Assembly System.Web.Mvc.dll, v4.0.0.0

I can see the following helper properties available:

 - Ajax
 - Html
 - Url

But nothing named Scripts.

Any ideas?

**EDIT:**

My Web.config file looks like this (untouched from the one that Visual Studio created):

      &lt;system.web.webPages.razor&gt;
        &lt;host factoryType=&quot;System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35&quot; /&gt;
        &lt;pages pageBaseType=&quot;System.Web.Mvc.WebViewPage&quot;&gt;
          &lt;namespaces&gt;
            &lt;add namespace=&quot;System.Web.Mvc&quot; /&gt;
            &lt;add namespace=&quot;System.Web.Mvc.Ajax&quot; /&gt;
            &lt;add namespace=&quot;System.Web.Mvc.Html&quot; /&gt;
            &lt;add namespace=&quot;System.Web.Routing&quot; /&gt;
          &lt;/namespaces&gt;
        &lt;/pages&gt;
      &lt;/system.web.webPages.razor&gt;

**EDIT #2:**

People are blogging about using the `@Scripts` helper:

 - [SCOTT HANSELMAN Blog][1]
 - [Codebetter.com][2]

Yet having just installed Visual Studio 2012 RC onto a fresh Windows 8 install I am still unable to use `@Scripts` even though Visual Studio adds it to the generated View!

**Solutions are presented below.**

I am not sure how to close this, because in the end an update seemed to resolve the issue. I double checked I had performed a clean install, using a new project. But the same failing project I had made works fine now after various updates and no manual obvious intervention. Thanks for all of the thoughts but there was definitely an issue at the time ;)


  [1]: http://www.hanselman.com/blog/VisualStudio2012RCIsReleasedTheBigWebRollup.aspx
  [2]: http://codebetter.com/howarddierking/2012/06/04/web-optimization-in-visual-studio-2012-rc

MVC 4 @Scripts &quot;does not exist&quot;

I&#39;m getting this Error:

&gt; The JSON request was too large to be deserialized.

Here&#39;s a scenario where this occurs. I have a class of country which hold a list of shipping ports of that country

    public class Country
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public List&lt;Port&gt; Ports { get; set; }
    }

I use KnockoutJS on the client side to make a cascading drop downs. So we have an array of two drop downs, where the first one is country, and the second one is ports of that country.

Everything is working fine so far, this my client side script:

    var k1 = k1 || {};
    $(document).ready(function () {
    
        k1.MarketInfoItem = function (removeable) {
            var self = this;
            self.CountryOfLoadingId = ko.observable();
            self.PortOfLoadingId = ko.observable();
            self.CountryOfDestinationId = ko.observable();
            self.PortOfDestinationId = ko.observable();  
        };

        k1.viewModel = function () {
            var marketInfoItems = ko.observableArray([]),
                countries = ko.observableArray([]),
                
    			saveMarketInfo = function () {
                    var jsonData = ko.toJSON(marketInfoItems);
                    $.ajax({
                        url: &#39;SaveMarketInfos&#39;,
                        type: &quot;POST&quot;,
                        data: jsonData,
                        datatype: &quot;json&quot;,
                        contentType: &quot;application/json charset=utf-8&quot;,
                        success: function (data) {
                            if (data) {
                                window.location.href = &quot;Fin&quot;;
                            } else {
                                alert(&quot;Can not save your market information now!&quot;);
                            }
    
                        },
                        error: function (data) { alert(&quot;Can not save your contacts now!&quot;); }
                    });
                },
    		     
                loadData = function () {
                    $.getJSON(&#39;../api/ListService/GetCountriesWithPorts&#39;, function (data) {
                        countries(data);
                    });
                };
            return {
                MarketInfoItems: marketInfoItems,
                Countries: countries,
                LoadData: loadData,
                SaveMarketInfo: saveMarketInfo,
            };
        } (); 

The problem occurs when a country like China is selected, which has *lots* of ports. So if you have 3 or 4 times &quot;China&quot; in your array and I want to send it to the server to save. The error occurs.

What should I do to remedy this?

Content Type	Original Author	Original Content on Stackoverflow
Question	Ray Cheng	View Question on Stackoverflow
Solution 1 - C#	used2could	View Answer on Stackoverflow

is there an asp.net fiddle?

C# Problem Overview

C# Solutions

Solution 1 - C#

UPDATE 1

UPDATE 2

UPDATE 3 (2017-03-19)

Adding and reading from a Config file

How to use --color-words with git add --patch?

Attributions