CompilerParameters.ReferencedAssemblies -- Add reference to System.Web.UI.WebControls

Question

I am compiling classes at run-time using the CodeDomProvider class. This works fine for classes only using the System namespace:

using System;

public class Test
{
    public String HelloWorld()
    {
        return "Hello World!";
    }
}

If I try to compile a class using System.Web.UI.WebControls though, I get this error:

{error CS0006: Metadata file 'System.Web.UI.WebControls' could not be found} System.CodeDom.Compiler.CompilerError

Here's a snippet of my code:

var cp = new CompilerParameters();

cp.ReferencedAssemblies.Add("System.Web.UI.WebControls");

How do I reference the System.Web.UI.WebControls namespace?

Answer 1

You can loop through all the currently loaded assemblies:

var assemblies = AppDomain.CurrentDomain
                            .GetAssemblies()
                            .Where(a => !a.IsDynamic)
                            .Select(a => a.Location);   

cp.ReferencedAssemblies.AddRange(assemblies.ToArray());

Answer 2

You reference assemblies, not namespaces. You should use MSDN to look up the name of the assembly that contains the classes you need to use: in this case it's going to be:

var cp = new CompilerParameters();
cp.ReferencedAssemblies.Add("System.Web.dll");

Answer 3

This proved to be a little less brute force in my case. I was building an addin and there were 730 assemblies loaded in the current domain so there was major lag involved.

var assemblies = someType.Assembly.GetReferencedAssemblies().ToList();
   var assemblyLocations =  
assemblies.Select(a => 
     Assembly.ReflectionOnlyLoad(a.FullName).Location).ToList();

assemblyLocations.Add(someType.Assembly.Location);

cp.ReferencedAssemblies.AddRange(assemblyLocations.ToArray());