Despite it being the furthest thing from Eric&#39;s mind, Roslyn has been [released as true Open Source][1] (Apache 2.0) and [is in fact now cross-platform.][2]

Miguel de Icaza of Xamarin [showed it running on Mono at BUILD.][3]

When Roslyn releases, it will become part of Mono. They are already [maintaining a branch at the Mono Git repo][4].


  [1]: https://roslyn.codeplex.com/
  [2]: http://tirania.org/blog/archive/2014/Apr-09.html
  [3]: http://channel9.msdn.com/Events/Build/2014/KEY02
  [4]: https://github.com/mono/roslyn

As @Govert has already mentioned in a comment, if you want to embed C# scripting capabilities you should simply use the Mono-equivalent library/tool: Mono-Csharp. (Especially because, even if Roslyn **could** run on Mono, its licence may dictate that you&#39;re not allowed to.)

This tool in the Mono world has existed much earlier than Roslyn BTW, and is open source. Here you have even a Microsoft employee blogging about it and uploading it to Nuget:

http://blog.davidebbo.com/2012/02/quick-fun-with-monos-csharp-compiler-as.html

I hope your game will kick ass!

To make things simple:

    string streamR = sr.ReadLine();  // sr.Readline results in:
                                     //                         one &quot;two two&quot;


I want to be able to save them as two different strings, remove all spaces EXCEPT for the spaces found between quotation marks. Therefore, what I need is:

    string 1 = one
    string 2 = two two



So far what I have found that works is the following code, but it removes the spaces within the quotes.
  
    //streamR.ReadLine only has two strings
      string[] splitter = streamR.Split(&#39; &#39;);
        str1 = splitter[0];
        // Only set str2 if the length is &gt;1
        str2 = splitter.Length &gt; 1 ? splitter[1] : string.Empty;

The output of this becomes

    one
    two

I have looked into https://stackoverflow.com/questions/554013/regular-expression-to-split-on-spaces-unless-in-quotes however I can&#39;t seem to get regex to work/understand the code, especially how to split them so they are two different strings. All the codes there give me a compiling error (I am using `System.Text.RegularExpressions`)



Split a string that has white spaces, unless they are enclosed within &quot;quotes&quot;?

What is the correct way to change the levels of a `factor` column in a `data.table`  (note: not data frame) 

      library(data.table)
      mydt &lt;- data.table(id=1:6, value=as.factor(c(&quot;A&quot;, &quot;A&quot;, &quot;B&quot;, &quot;B&quot;, &quot;B&quot;, &quot;C&quot;)), key=&quot;id&quot;)

      mydt[, levels(value)]
      [1] &quot;A&quot; &quot;B&quot; &quot;C&quot;


I am looking for something like: 

    mydt[, levels(value) &lt;- c(&quot;X&quot;, &quot;Y&quot;, &quot;Z&quot;)]

But of course, the above line does not work. 
    
        # Actual               # Expected result
        &gt; mydt                  &gt; mydt
           id value                id value
        1:  1     A             1:  1     X
        2:  2     A             2:  2     X
        3:  3     B             3:  3     Y
        4:  4     B             4:  4     Y
        5:  5     B             5:  5     Y
        6:  6     C             6:  6     Z

How does one change the levels of a factor column in a data.table

I&#39;ve been looking at [Roslyn][1] for quite some time now, and I&#39;m curious and excited about it. One thing I noticed is that they mentioned that the compiler is re-written in managed code. This raises the question of whether Roslyn is able to run on non-.NET virtual machines, such as [Mono][2].

I would *really* love to embed C# scripting using Roslyn in my video games, and to use many of their other features in my applications, but I&#39;m wondering if using Roslyn will break the ability for it to run on Mono.

Has anyone tried running Roslyn on Mono? Is it possible? Why or why not?

To clarify, I&#39;m interested in both whether the managed assembly can run on Mono, and whether it can generate assemblies that mono can run.

  [1]: https://en.wikipedia.org/wiki/.NET_Compiler_Platform
  [2]: http://en.wikipedia.org/wiki/Mono_%28software%29


Is Roslyn cross platform?

I've been looking at <a href="https://en.wikipedia.org/wiki/.NET_Compiler_Platform" target="_blank" rel="noopener noreferrer">Roslyn</a> for quite some time now, and I'm curious and excited about it. One thing I noticed is that they mentioned that the compiler is re-written in managed code. This raises the question of whether Roslyn is able to run on non-.NET virtual machines, such as <a href="http://en.wikipedia.org/wiki/Mono_%28software%29" target="_blank" rel="noopener noreferrer">Mono</a>.
I would really love to embed C# scripting using Roslyn in my video games, and to use many of their other features in my applications, but I'm wondering if using Roslyn will break the ability for it to run on Mono.
Has anyone tried running Roslyn on Mono? Is it possible? Why or why not?
To clarify, I'm interested in both whether the managed assembly can run on Mono, and whether it can generate assemblies that mono can run.

I am new to asynchronous programming, so after going through some async sample codes, I thought of writing a simple async code

I created a simple Winform application and inside the Form I wrote the following code. But its just not working

    private Task&lt;string&gt; methodAsync() {
        Thread.Sleep(10000);
        return &quot;Hello&quot;; //Error: Cannot implicitly convert type &#39;string&#39; to &#39;System.Threading.Tasks.Task&lt;string&gt;&#39;
    }

    private async void button1_Click(object sender, EventArgs e)
    {
        string s = await methodAsync();
        MessageBox.Show(s);
    }

Could someone please put some light here..

Cannot implicitly convert type &#39;string&#39; to &#39;System.Threading.Tasks.Task&lt;string&gt;&#39;

    //Get PropertyDescriptor object for the given property name
    var propDesc = TypeDescriptor.GetProperties(typeof(T))[propName];

    //Get FillAttributes methodinfo delegate
    var methodInfo = propDesc.GetType().GetMethods(BindingFlags.Instance | BindingFlags.Public |
                                                          BindingFlags.NonPublic)
        .FirstOrDefault(m =&gt; m.IsFamily || m.IsPublic &amp;&amp; m.Name == &quot;FillAttributes&quot;);

    //Create Validation attribute
    var attribute = new RequiredAttribute();
    var  attributes= new ValidationAttribute[]{attribute};
   
    //Invoke FillAttribute method
    methodInfo.Invoke(propDesc, new object[] { attributes });

Hi I am trying to add Validation attribute at runtime using the above code. However I am getting the below exception:

&gt; Collection was of a fixed size


How to add an attribute to a property at runtime

I am trying to test a method - and getting an error:

&gt; Cannot create an instance of the variable type &#39;Item&#39; because it does not have the new() constraint

Required information for below:

    public interface IHasRect
    {
        Rectangle Rectangle { get; }
    }

Helper class:

    class Item : IHasRect
    {
        public Item(Point p, int size)
        {
            m_size = size;
            m_rectangle = new Rectangle(p.X, p.Y, m_size, m_size); 
        }
    }

For the function to be tested, I need to instantiate an object...

    public class SomeClass&lt;T&gt; where T : IHasRect

The test:

    public void CountTestHelper&lt;Item&gt;() where Item : IHasRect
    {
        Rectangle rectangle = new Rectangle(0, 0, 100, 100); 
        SomeClass&lt;Item&gt; target = new SomeClass&lt;Item&gt;(rectangle);            
        Point p = new Point(10,10);
        Item i = new Item(p, 10);      // error here        
        ...
    }
    [TestMethod()]
    public void CountTest()
    {
        CountTestHelper&lt;Item&gt;();
    }   

   
I am trying to understand what this error means, or how to fix it, by reading http://msdn.microsoft.com/en-us/library/d5x73970.aspx and http://msdn.microsoft.com/en-us/library/x3y47hd4.aspx - but it doesn&#39;t help.

I don&#39;t understand this error - I have already constrained the &quot;SomeClass&quot; to be of &lt;Item&gt; type. I cannot constrain the entire Test class (the unit test class generated by Visual Studio, which contains all the tests) - I will get a number of other errors otherwise. The Item class doesn&#39;t have any template...

Cannot create an instance of the variable type &#39;Item&#39; because it does not have the new() constraint

I want to post some form data to a specified URL that isn&#39;t inside my own web application. It has the same domain, such like &quot;domain.client.nl&quot;. The web application has a url &quot;web.domain.client.nl&quot; en the url where I want to post to is &quot;idp.domain.client.nl&quot;. 
But my code does nothing..... does someone knows what I&#39;m doing wrong? 

Wouter

    StringBuilder postData = new StringBuilder();
    postData.Append(HttpUtility.UrlEncode(String.Format(&quot;username={0}&amp;&quot;, uname)));
    postData.Append(HttpUtility.UrlEncode(String.Format(&quot;password={0}&amp;&quot;, pword)));
    postData.Append(HttpUtility.UrlEncode(String.Format(&quot;url_success={0}&amp;&quot;, urlSuccess)));
    postData.Append(HttpUtility.UrlEncode(String.Format(&quot;url_failed={0}&quot;, urlFailed)));
    
    ASCIIEncoding ascii = new ASCIIEncoding();
    byte[] postBytes = ascii.GetBytes(postData.ToString());
    
    // set up request object
    HttpWebRequest request;
    try
    {
    	request = (HttpWebRequest)HttpWebRequest.Create(WebSiteConstants.UrlIdp);
    }
    catch (UriFormatException)
    {
    	request = null;
    }
    if (request == null)
    	throw new ApplicationException(&quot;Invalid URL: &quot; + WebSiteConstants.UrlIdp);
    
    request.Method = &quot;POST&quot;;
    request.ContentType = &quot;application/x-www-form-urlencoded&quot;;
    request.ContentLength = postBytes.Length;
    request.UserAgent = &quot;Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)&quot;;
    
    // add post data to request
    Stream postStream = request.GetRequestStream();
    postStream.Write(postBytes, 0, postBytes.Length);
    postStream.Flush();
    postStream.Close();

Post form data using HttpWebRequest

I&#39;m trying to run NuGet on Linux (Ubuntu 12). I have Mono 3.0.6 (compiled from source).

&lt;!-- language-all: lang-none --&gt;

    $ mono --runtime=v4.0.30319 .nuget/NuGet.exe update -self
    Checking for updates from https://nuget.org/api/v2/.
    Error getting response stream (Write: The authentication or decryption has failed.): SendFailure

The error is due to some certificate (the nuget.org one most likely) not being trusted, I gather. This [blog post has more details](http://monomvc.wordpress.com/2012/03/06/nuget-on-mono/).

So I&#39;ve run:

    $ mozroots --import --sync
    $ certmgr -ssl https://go.microsoft.com
    $ certmgr -ssl https://nugetgallery.blob.core.windows.net
    $ certmgr -ssl https://nuget.org

... to no avail.

NuGet Version is 2.3.0.0 (although I started out with some older version that also did not work either).

How can I fix this error?


NuGet on Linux: Error getting response stream

Travis CI continuous integration service officially supports many [languages](http://about.travis-ci.org/docs/#Specific-Language-Help), but not C# or F#. 

Can I use it with my .net projects?

How do I use Travis-CI with C# or F#

I have a really strange problem with `WebRequest` in a `ServiceStack` web application (hosted by XSP on Mono).
It seems that the registration of request modules works in a very strange way; I am using `WebRequest` to create an HTTP request, and it is failing because it was not able to find a creator for that &quot;prefix&quot; (HTTP).

The exception I am seeing is `NotSupportedException`, and I was able to track it to the fact that no creator is registered for the HTTP prefix (I am hitting https://github.com/mono/mono/blob/master/mcs/class/System/System.Net/WebRequest.cs, around line 479)

**EDIT:** more details: `NotSupportedException` is thrown by `WebRequest.GetCreator`, which uses the URL prefix as a key to choose which creator to return; in my case, a `HttpRequestCreator`. The exception is thrown because there is no creator registered for the &quot;HTTP&quot; prefix (actually, there are no creators at all).

So I searched around a little bit, dug into Mono sources, and found that modules are (or should be) added to the `webRequestModules` section of `system.web` in one of the various _*.config_ files.

I looked at my _machine.config_ file, and there it is:

    System.Net.HttpRequestCreator, System, Version=4.0.0.0
Looking at [WebRequest Mono sources](https://github.com/mono/mono/blob/master/mcs/class/System/System.Net/WebRequest.cs) 
it seems that prefixes are added from configuration(s) inside the class static constructor (not a good choice, IMHO, but still.. it should work).

To test it, I tried to add an `HttpRequestCreator` to `system.net/webRequestModules` in my `web.config`; this is loaded by XSP/Mono and results in a duplicate key exception (which is expected since `HttpRequestCreator` should be already loaded, as it is already present in _machine.config_).

**Even stranger:** if I add a mock handler for Http, like this:

    bool res = System.Net.WebRequest.RegisterPrefix (&quot;http&quot;, new MyHttpRequestCreator ());
    Debug.Assert (res == false);

The assertion sometimes pass... sometimes not!
(`RegisterPrefix` returns &quot;false&quot; if a creator for the same prefix is already registered; I expect it always to return false, but this is not the case! Again, it is completely random)

When the registration &quot;fails&quot; (i.e., returns false because an &quot;HTTP&quot; prefix is already registered), then the `WebRequest` can create requests for HTTP. It is as if calling `RegisterPrefix` &quot;wakes up&quot; the static constructor and let it run.

**I am perplexed**: it seems like a race condition in the execution of the static constructor of `WebRequest`, but this does not make sense (the runtime protects static constructors with a lock, IIRC)

What am I missing?
How could I solve or work around this problem?
Is it my fault (misunderstanding or missing something), or does it look like a Mono bug, so should I submit it?

Details:
&gt;mono --version&lt;br/&gt;
&gt;Mono JIT compiler version 3.0.6 (Debian 3.0.6+dfsg-1~exp1~pre1)

Possibly related, unanswered question: 
 - https://stackoverflow.com/q/17427255/863564

&quot;NotSupportedException&quot; when WebRequest is unable to find a creator for that prefix

What is the relationship between [Xamarin][1] and [Mono][2](Are they the same product)?

Is the Monodevelop IDE related to Mono?


  [1]: http://www.xamarin.com
  [2]: http://www.mono-project.com/Main_Page

Xamarin vs. Mono vs. Monodevelop

I&#39;m trying to get the SHA1 fingerprint so I can get an Google API key.
Im in the following directory: 

&gt; /Library/Java/JavaVirtualMachines/jdk1.8.0_20.jdk/Contents/Home/bin

Then I execute the command from the google site : 

&gt; keytool -list -v -keystore mystore.keystore

But it gives this error:

    keytool error: java.lang.Exception: Keystore file does not exist: mystore.keystore
    java.lang.Exception: Keystore file does not exist: mystore.keystore
    	at sun.security.tools.keytool.Main.doCommands(Main.java:742)
    	at sun.security.tools.keytool.Main.run(Main.java:340)
    	at sun.security.tools.keytool.Main.main(Main.java:333)

I followed tutorials but I can&#39;t get it to work!
Does anyone know what I am doing wrong?

BTW: I&#39;m using a Macbook Pro with Xamarin Studio 5.5.2.


Keystore file doesn&#39;t exist

I modified the example that comes with the new version of Roslyn that was released yesterday to use dynamic and ExpandoObject but I am getting a compiler error which I am not sure how to fix. The error is:

&gt; (7,21): error CS0656: Missing compiler required member &#39;Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo.Create&#39;

Can you not use dynamics in the new compiler yet? How can I fix this? Here is the example that I updated:

    [TestMethod]
    public void EndToEndCompileAndRun()
    {
        var text = @&quot;using System.Dynamic;
        public class Calculator
        {
            public static object Evaluate()
            {
                dynamic x = new ExpandoObject();
                x.Result = 42;
                return x.Result;
            } 
        }&quot;;
    
        var tree = SyntaxFactory.ParseSyntaxTree(text);
        var compilation = CSharpCompilation.Create(
            &quot;calc.dll&quot;,
            options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary),
            syntaxTrees: new[] {tree},
            references: new[] {new MetadataFileReference(typeof (object).Assembly.Location), new MetadataFileReference(typeof (ExpandoObject).Assembly.Location)});
    
        Assembly compiledAssembly;
        using (var stream = new MemoryStream())
        {
            var compileResult = compilation.Emit(stream);
            compiledAssembly = Assembly.Load(stream.GetBuffer());
        }
    
        Type calculator = compiledAssembly.GetType(&quot;Calculator&quot;);
        MethodInfo evaluate = calculator.GetMethod(&quot;Evaluate&quot;);
        string answer = evaluate.Invoke(null, null).ToString();
    
        Assert.AreEqual(&quot;42&quot;, answer);
    }

Using System.Dynamic in Roslyn

In C# 6, you can use the [`nameof()`][1] operator to get a string containing the name of a variable or a type.

Is this evaluated at compile-time, or at runtime via some Roslyn API?

  [1]: https://msdn.microsoft.com/en-us/library/dn986596.aspx

Is nameof() evaluated at compile-time?

I&#39;m building a set of code diagnostics using Roslyn (in VS2015 Preview). Ideally, I&#39;d like any errors they produce to act as persistent errors, just as if I were violating a normal language rule.

There are a bunch of options, but I&#39;m having a hard time getting any of them to work consistently. I&#39;ve managed to implement a rudimentary syntax node action, i.e. one registered with 

    context.RegisterSyntaxNodeAction(AnalyzeSyntaxNode, SyntaxKind.InvocationExpression);

in the `Initialize` method of my diagnostic class. Lo and behold, when I open up a file which violates this diagnostic (while running the VSIX project), VS2015 shows an error:

- Red squiggle under the right bit of code
- Red block in the margin
- Error in the error list

However, the error goes away when I close the file.

I&#39;ve tried using `context.RegisterCompilationEndAction` as well, but this has two problems:

- It seems to fire inconsistently. *Usually* when I open the solution it fires, but not always. It doesn&#39;t fire on a clean/rebuild, which seems odd.
- Although diagnostics created *directly* in the analysis method fire, in order to implement the diagnostics I&#39;m using a visitor, like this - which may be inept:

        private static void AnalyzeEndCompilation(CompilationEndAnalysisContext context)
        {
            foreach (var tree in context.Compilation.SyntaxTrees)
            {
                var visitor = new ReportingVisitor(context.Compilation.GetSemanticModel(tree));
                visitor.Visit(tree.GetRoot());
                foreach (var diagnostic in visitor.Diagnostics)
                {
                    context.ReportDiagnostic(diagnostic);
                }
            }
        }

 I know that the diagnostics are being created - a breakpoint on the `ReportDiagnostic` line is hit several times - but I&#39;m not seeing anything in the error list. (Whereas a similar `ReportDiagnostic` call at the start of the method, or one per syntax tree with the file path, *does* get shown.)

What am I doing wrong here? The first approach (a syntax node action) would be ideal if feasible - it gives me exactly the context I need. Is there some setting in the project properties that I need to make the compiler use that for &quot;full project&quot; compilation as well as just interactive &quot;in the IDE&quot; handling? Is this perhaps just a bit of Roslyn integration which isn&#39;t quite finished yet?

(I can include the full code for the class if it would be useful - in this case I suspect it would be more noise than signal though.)

How can I make my code diagnostic syntax node action work on closed files?

I looked at the source code at http://referencesource.microsoft.com/, and it appears all the source code is in C#.

I also looked at the source code for the new C# compiler platform ([Roslyn][1]), and it is also in C#. How is that possible? Is C# language compiler written in C#? Or am I missing something obvious? If C# compiler is written in C# then how does it work?

  [1]: https://en.wikipedia.org/wiki/.NET_Compiler_Platform


In which language is the C# compiler written?

I am testing Visual Studio 2015 with C# 6.0 but the language features are not working. In an MVC web application, the following code does compile:

    if (!string.IsNullOrWhiteSpace(Model.Profile?.TypeName))
    {
        // More logic here...
    }

However, when I run the application via Debug and IIS Express, I get the following error:

&gt; CS1525: Invalid expression term &#39;.&#39;

How do I enable these features?

Content Type	Original Author	Original Content on Stackoverflow
Question	mirhagk	View Question on Stackoverflow
Solution 1 - C#	Justin	View Answer on Stackoverflow
Solution 2 - C#	knocte	View Answer on Stackoverflow

Is Roslyn cross platform?

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

How does one change the levels of a factor column in a data.table

Split a string that has white spaces, unless they are enclosed within "quotes"?

Attributions