How best to create and execute a method in a .NET (C#) class dynamically through configuration

Question

I'm thinking of something along the lines of the "Inline Task" in MsBuild. For reference: http://msdn.microsoft.com/en-us/library/dd722601.aspx

I'd like to find or create a framework which allows me to override a method via configuration. For example if I have a well known base class which has a method Execute(args), how can I supply an overridden method implementation at deployment time, without requiring new code, build, release cycle? I would like to actually plug in the method body into a config file or preferably a database table.

I assume this would be done either with code dom, dynamic language integration, or perhaps something like powershell(?). I'm looking for recommendations or perhaps a library someone has already written.

The application is written in C#. Preferably the extension would also be in C#, but I'm open to other ideas as well.

Update: Technically I don't even have to actually override a method. It would be sufficient to just be able to dynamically execute some external source code, passing in an arg and returning a result.

Update. I ended up writing code to instantiate a PowerShell object and execute a script dynamically to return a value. Here is a snippet of code I used.

    public static Collection<PSObject> ExecuteScript(string code, string variableName, object variableValue)
        {
            PowerShell ps = PowerShell.Create();    

            ps.AddScript(code);

            if (!string.IsNullOrWhiteSpace(variableName))
            {                   
                ps.Runspace.SessionStateProxy.SetVariable(variableName, variableValue);
            }

            var result = ps.Invoke();

            return result;
        }

Then in the calling code, I simply check the first PSObject in the return value, and pull the resulting value from it. It works great. Thanks for all the responses.

Answer 1

Here are two examples of dynamic execution. I have used neither though so I can't comment further.

http://www.codeproject.com/KB/dotnet/evaluator.aspx
http://www.csharpfriends.com/articles/getarticle.aspx?articleid=118

Regarding namespaces, from the second article you can add assemblies through the CompilerParameter class.

// Create the C# compiler
CSharpCodeProvider csCompiler = new CSharpCodeProvider();
ICodeCompiler iCodeCompiler = csCompiler.CreateCompiler();

// input params for the compiler
CompilerParameters compilerParams = new CompilerParameters();
compilerParams.OutputAssembly = "CSharpFriends.dll";
compilerParams.ReferencedAssemblies.Add("system.dll");