It is used when/if you use the [`dynamic` keyword][1] in your project. The assembly contains the C# runtime binder. 

The C# compiler has essentially been extracted out into a library so that it can emit, compile and run code needed to support the `dynamic` keyword. The first time you use `dynamic` in your code, this assembly (as well as System.dll, System.Core.dll and System.Dynamic.dll) will get loaded into your AppDomain.


  [1]: http://msdn.microsoft.com/en-us/library/dd264741.aspx

In the following code snippet, the `Color` enum is declared within the `Car` class in order to limit the scope of the enum and to try not to &quot;pollute&quot; the global namespace.

    class Car
    {
    public:
    
       enum Color
       {
          RED,
          BLUE,
          WHITE
       };
    
       void SetColor( Car::Color color )
       {
          _color = color;
       }
    
       Car::Color GetColor() const
       {
          return _color;
       }
    
    private:
    
       Car::Color _color;
    
    };

(1) Is this a good way to limit the scope of the `Color` enum?  Or, should I declare it outside of the `Car` class, but possibly within its own namespace or struct?  I just came across this article today, which advocates the latter and discusses some nice points about enums:  [http://gamesfromwithin.com/stupid-c-tricks-2-better-enums][1].

(2) In this example, when working *within* the class, is it best to code the enum as `Car::Color`, or would just `Color` suffice?  (I assume the former is better, just in case there is another `Color` enum declared in the global namespace.  That way, at least, we are explicit about the enum to we are referring.)

  [1]: http://gamesfromwithin.com/stupid-c-tricks-2-better-enums

Declaring an enum within a class

I need to write a file in the same folder where a console ClickOnce `.application` (executable file) resides. The folder where it launches from.

I tried using `Application.StartupPath` &amp; `Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)`
but the path is pointing to a subfolder under `c:\Documents &amp; Settings`. How do I get the path where the `.application` resides in?


How to get folder path for ClickOnce application

This DLL is added by default in Visual Studio 2010 projects. What is this new assembly used for? It does not seem to contain much after looking at it using Reflector and Google does not seem to have much to say about it either.

What is Microsoft.csharp.dll in .NET 4.0

<p>This DLL is added by default in Visual Studio 2010 projects. What is this new assembly used for? It does not seem to contain much after looking at it using Reflector and Google does not seem to have much to say about it either.</p>


The .NET MemoryStream does not appear to have a .Reset or .Clear method.

I was thinking of using the following code to accomplish this:

    ms.Seek(0, IO.SeekOrigin.Begin)
    ms.SetLength(0)

What is the proper way to clear or reset an existing .NET MemoryStream?


Reset or Clear .NET MemoryStream

In a C# application, how can I find out if a WPF window is in the primary monitor or another monitor?

How do I know what monitor a WPF window is in

When debugging in Visual Studio, sometimes I add a breakpoint but it&#39;s hollow and VS says &quot;The breakpoint will not currently be hit. The source code is different from the original version.&quot; Obviously this prevents me from being able to debug.

What on earth does the message mean? What original version? If I&#39;ve just opened up the solution and not made any changes whatsoever to the code, how can there be an &#39;original version&#39;?

&quot;The breakpoint will not currently be hit. The source code is different from the original version.&quot; What does this mean?

Given a datasource like that:

    var c = new Car[]
    {
      new Car{ Color=&quot;Blue&quot;, Price=28000},
      new Car{ Color=&quot;Red&quot;, Price=54000},
      new Car{ Color=&quot;Pink&quot;, Price=9999},
      // ..
    };

How can I find the **index** of the first car satisfying a certain condition with LINQ?

EDIT:

I could think of something like this but it looks horrible:

    int firstItem = someItems.Select((item, index) =&gt; new    
    {    
        ItemName = item.Color,    
        Position = index    
    }).Where(i =&gt; i.ItemName == &quot;purple&quot;)    
      .First()    
      .Position;

Will it be the best to solve this with a plain old loop?


How to get index using LINQ?

It seems like optimization is a lost art these days. Wasn&#39;t there a time when all programmers squeezed every ounce of efficiency from their code? Often doing so while walking five miles in the snow?

In the spirit of bringing back a lost art, what are some tips that you know of for simple (or perhaps complex) changes to optimize C#/.NET code? Since it&#39;s such a broad thing that depends on what one is trying to accomplish it&#39;d help to provide context with your tip. For instance:

  - When concatenating many strings together use &lt;code&gt;StringBuilder&lt;/code&gt; instead. See link at the bottom for caveats on this.
  - Use &lt;code&gt;string.Compare&lt;/code&gt; to compare two strings instead of doing something like &lt;code&gt;string1.ToLower() == string2.ToLower()&lt;/code&gt;

The general consensus so far seems to be measuring is key. This kind of misses the point: measuring doesn&#39;t tell you what&#39;s wrong, or what to do about it if you run into a bottleneck. I ran into the string concatenation bottleneck once and had no idea what to do about it, so these tips are useful.

My point for even posting this is to have a place for common bottlenecks and how they can be avoided before even running into them. It&#39;s not even necessarily about plug and play code that anyone should blindly follow, but more about gaining an understanding that performance should be thought about, at least somewhat, and that there&#39;s some common pitfalls to look out for.

I can see though that it might be useful to also know why a tip is useful and where it should be applied. For the &lt;code&gt;StringBuilder&lt;/code&gt; tip I found the help I did long ago at [here on Jon Skeet&#39;s site][1]. 

  [1]: http://www.yoda.arachsys.com/csharp/stringbuilder.html


Tips for optimizing C#/.NET programs

In VS2010 they added to all projects a virtual directory called &quot;External Dependencies&quot;:

![alt text][1]

It really bothers me especially because if there is a normal folder named &quot;Apple&quot; and one named &quot;Deep&quot; it will be in between the two, and also the information it gives is, in my opinion, completely useless.

*****

**Is there any way to remove or hide it?**


  [1]: http://koper.wowpanda.net/externaldeps.PNG
  [2]: http://koper.wowpanda.net/externaldeps2.PNG

VS2010: how to remove/hide the &quot;External Dependencies&quot; folder in Solution Explorer

I am creating a web application on the .NET 4.0 framework (beta2) in C#.

When I try to use a assembly called &quot;ActiveHomeScriptLib&quot;, I get the following error:

&gt; Interop type
&gt; &#39;ActiveHomeScriptLib.ActiveHomeClass&#39;
&gt; cannot be embedded. Use the applicable
&gt; interface instead.

When I change the framework to version 3.5, I don&#39;t have any errors.

What is an Interop Type and why does this only occur when I use the 4.0 framework?


Interop type cannot be embedded

I cannot figure out how to get rid of errors that basically should not be halting my compile in [Visual&amp;nbsp;Studio&amp;nbsp;2010][1] and should not be show stoppers, or at least I will fix them later, but I don&#39;t want the compile to just error and halt on these kinds of problems.

For example, I&#39;m getting the following error:

&gt; Error 1 Warning as Error: XML comment
&gt; on
&gt; &#39;ScrewTurn.Wiki.SearchEngine.Relevance.Finalize(float)&#39;
&gt; has a paramref tag for &#39;IsFinalized&#39;,
&gt; but there is no parameter by that name
&gt; C:\www\Wiki\Screwturn3_0_2_509\SearchEngine\Relevance.cs
&gt; 60 70 SearchEngine

for this code:

      /// &lt;summary&gt;
      /// Normalizes the relevance after finalization.
      /// &lt;/summary&gt;
      /// &lt;param name=&quot;factor&quot;&gt;The normalization factor.&lt;/param&gt;
      /// &lt;exception cref=&quot;InvalidOperationException&quot;&gt;If &lt;paramref name=&quot;IsFinalized&quot;/&gt; is &lt;c&gt;false&lt;/c&gt; (&lt;see cref=&quot;M:Finalize&quot;/&gt; was not called).&lt;/exception&gt;
      public void NormalizeAfterFinalization(float factor) {
          if (factor &lt; 0)
              throw new ArgumentOutOfRangeException(&quot;factor&quot;, &quot;Factor must be greater than or equal to zero&quot;);

          if (!isFinalized)
              throw new InvalidOperationException(&quot;Normalization can be performed only after finalization&quot;);
          value = value * factor;
      }

I looked in menu *Tools* -&gt; *Options*, and I don&#39;t see where I can tweak the compiler and tell it not to worry about comment or XHTML based errors.

  [1]: http://en.wikipedia.org/wiki/Microsoft_Visual_Studio#Visual_Studio_2010


Warning as error - How to get rid of these

After installing and using Visual Studio 2010, I&#39;m seeing some newer file types (at least with C++ projects ... don&#39;t know about the other types) as compared to 2008.  e.g. .sdf, .opensdf, which I guess are the replacement for ncb files with Intellisense info stored in SQL Server Compact files?  I also notice .log files are generated, which appear to be build logs.

Given this, what&#39;s safe to add to my global ignore pattern?  Off the bat, I&#39;d assume .sdf, .opensdf, but what else?


What should be contained in a global source code control ignore pattern for Visual Studio 2010?

I installed .NET 4.0 and VS 2010 RC on my laptop and MSBuild was automatically installed.  I was hoping to build a continuous integration server by just installing the .NET SDK without VS 2010, so I downloaded the .NET 4.0 Framework from Microsoft at this &lt;a href=&quot;http://www.microsoft.com/downloads/details.aspx?FamilyID=a9ef9a95-58d2-4e51-a4b7-bea3cc6962cb&amp;displaylang=en&quot;&gt;link&lt;/a&gt;.  Unfortunately, it doesn&#39;t appear to have installed MSBuild with this download (or at least I can&#39;t find it).

Is this link the appropriate link for the SDK, or is this just the runtime?  If not, where is the link for the SDK?

I kind of doubt it is the entire SDK as it is only 35MB where the .NET 3.5 SP1 download was over 200MB.

Installing MSBuild 4.0 without Visual Studio 2010

I need to move all the hard coded strings in my source code in .resx files. Is there a tool that could help me find all the hardcoded strings within C# code?

Find all source hardcoded strings

Is there any 64 bit Visual Studio at all? Why not?



Visual Studio 64 bit?

Using c# 4.0 -- building an interface and a class that implements the interface. I want to declare an optional parameter in the interface and have it be reflected in the class. So, I have the following:

     public interface IFoo
     {
          void Bar(int i, int j=0);
     }

     public class Foo
     {
          void Bar(int i, int j=0) { // do stuff }
     }

This compiles, but it doesn&#39;t look right. The interface needs to have the optional parameters, because otherwise it doesn&#39;t reflect correctly in the interface method signature. 

Should I skip the optional parameter and just use a nullable type? Or will this work as intended with no side effects or consequences?

Optional parameters for interfaces

Code below is working well as long as I have class `ClassSameAssembly` in same assembly as class `Program`.
But when I move class `ClassSameAssembly` to a separate assembly, a `RuntimeBinderException` (see below) is thrown.
Is it possible to resolve it?    

    using System;

    namespace ConsoleApplication2
    {
        public static class ClassSameAssembly
        {
            public static dynamic GetValues()
            {
                return new
                {
                    Name = &quot;Michael&quot;, Age = 20
                };
            }
        }

        internal class Program
        {
            private static void Main(string[] args)
            {
                var d = ClassSameAssembly.GetValues();
                Console.WriteLine(&quot;{0} is {1} years old&quot;, d.Name, d.Age);
            }
        }
    }

`Microsoft.CSharp.RuntimeBinder.RuntimeBinderException`: **&#39;object&#39; does not contain a definition for &#39;Name&#39;**

    at CallSite.Target(Closure , CallSite , Object )
    at System.Dynamic.UpdateDelegates.UpdateAndExecute1[T0,TRet](CallSite site, T0 arg0)
    at ConsoleApplication2.Program.Main(String[] args) in C:\temp\Projects\ConsoleApplication2\ConsoleApplication2\Program.cs:line 23


C# ‘dynamic’ cannot access properties from anonymous types declared in another assembly

I&#39;m having a little trouble understanding how I would use covariance and contravariance in the real world.

So far, the only examples I&#39;ve seen have been the same old array example.

    object[] objectArray = new string[] { &quot;string 1&quot;, &quot;string 2&quot; };


It would be nice to see an example that would allow me to use it during my development if I could see it being used elsewhere.


Covariance and contravariance real world example

When should one use dynamic keyword in c# 4.0?.......Any good example with dynamic keyword in c# 4.0 that explains its usage.... 

When should one use dynamic keyword in c# 4.0?

There is a lot of information about new features and classes in new 4.0 however there are also changes that may affect existing applications, for example

 1. Timespan now implements IFormattable and old *string.Format()* with invalid options will throw exception instead of calling simple ToString(). However, CLR team provides a nice feature to enable behaviour from previous version with configuration setting - TimeSpan_LegacyFormatMode .
 
  [CLR Inside Out][1]

 
 2. Access to events inside the class where they are declared using += or -= will lead to call add/remove generated accessors that return void. Some code won&#39;t even compile in 4.0.

 [Chris Burrows Blog][2]

 3. CAS is deprecated and to enable it one still need to use special setting in  configuration - NetFx40_LegacySecurityPolicy


So I wonder what are other changes and is it possible to find at least preliminary list of changes that will or may break existing functionality with release of .NET 4.0 ? 


  [1]: http://msdn.microsoft.com/ru-ru/magazine/ee309881%28en-us%29.aspx
  [2]: http://blogs.msdn.com/cburrows/archive/2010/03/18/events-get-a-little-overhaul-in-c-4-part-iii-breaking-changes.aspx

Breaking changes in .NET 4.0

There doesn&#39;t appear to be a generic implementation of `OrderedDictionary` (which is in the `System.Collections.Specialized` namespace) in .NET 3.5. Is there one that I&#39;m missing? 

I&#39;ve found implementations out there to provide the functionality, but wondered if/why there isn&#39;t a generic implementation out-of-the-box and if anyone knows whether it&#39;s something in .NET 4.0?


No generic implementation of OrderedDictionary?

`%windir%\Microsoft.NET\assembly\` is the new [GAC][1]. Does it mean now we have to manage two GACs, one for .NET 2.0-3.5 applications and the other for .NET 4.0 applications?

The question is, why?

  [1]: http://en.wikipedia.org/wiki/Global_Assembly_Cache



.NET 4.0 has a new GAC, why?

I recently moved to Visual Studio 2010 and upgraded my website to work with .NET Framework 4. (From VS 2008 - Framework 3.5)

What are things I need to know to improve site speed, readability or memory use? 

Content Type	Original Author	Original Content on Stackoverflow
Question	anon	View Question on Stackoverflow
Solution 1 - .Net	adrianbanks	View Answer on Stackoverflow
Solution 2 - .Net	TomTom	View Answer on Stackoverflow

What is Microsoft.csharp.dll in .NET 4.0

.Net Problem Overview

.Net Solutions

Solution 1 - .Net

Solution 2 - .Net

How to get folder path for ClickOnce application

Declaring an enum within a class

Attributions