C# dynamic compilation and "Microsoft.CSharp.dll" error

Question

I'm doing the example that can be found here. So I'm trying to run IronPython in a C# script:

Python:

def hello(name):
    print "Hello " + name + "! Welcome to IronPython!"
    return

def add(x, y):
    print "%i + %i = %i" % (x, y, (x + y))
    return

def multiply(x, y):
    print "%i * %i = %i" % (x, y, (x * y))
    return

C#:

using IronPython.Hosting;
using IronPython.Runtime;
using Microsoft.Scripting.Hosting;
using System;

namespace IntroIronPython
{
    class IronPythonMain
    {
        static void Main(string[] args)
        {
            // Create a new ScriptRuntime for IronPython
            Console.WriteLine("Loading IronPython Runtime...");
            ScriptRuntime python = Python.CreateRuntime();

            try
            {
                // Attempt to load the python file
                Console.WriteLine("Loading Python File...");
                // Create a Dynamic Type for our Python File
                dynamic pyfile = python.UseFile("PythonFunctions.py");
                Console.WriteLine("Python File Loaded!");

                Console.WriteLine("Running Python Commands...\n");

                // Call the hello(name) function
                pyfile.hello("Urda");
                …

And from here I have this error: "Dynamic Operation cannot be compiled without "Microsoft.CSharp.dll" assembly reference." And I seriously don't understand what that is about, what did I forget to add?

In my references I have:

Thx for your help.

Ps: I'm on MonoDevelop.

Genna

Answer 1

Ok. Basically, my mistake was linked to the fact that I added my IronPython assemblies from the wrong platform. Verify that:

• Target Framework: 4.0

• Add all the assemblies provided by IronPython in [IronPython-2.7.3]->[Platforms]->[Net40].

Thx to everyone who gave me advices.

Ps:Now, of course, there is another problem… But it's not about that topic anymore.

Genna

Make sure you flag your own answer as the solution so future visitors can see you solved the problem! Also I'm glad you found and chose to use my example :) – Zacek

This was my problem as well. I had added my references using the ".NET" tab in Visual Studio C# 2010 Express. I think the original files that appeared may only have been from the Net35 directory. Be aware of the Path in the Add References dialogue box. When I added them from IronPython 2.7\Platforms\Net40 the build succeeded, and both sets of assemblies now appear on the .Net tab in Add References. (This may have been the case before too, I just didn't notice). – Balefire

Answer 2

This is what helped me. I am using Xamarian Studio v5.8.1 (build 8) to write a C# program. I just had to right click "References" -> "Edit References" -> started typing "Microsoft" in the search bar -> Checked the box next to "Microsoft.CSharp" -> and clicked "OK".

I just saved and ran the program after that - everything works as expected!

Loaning

Answer 3

Microsoft.CSharp.dll contains the dynamic portion of the C# compiler. Any time you use dynamic in your code, you need a reference to it. I'm not familiar with MonoDevelop, but you'll probably have to set the target framework to 4.0, and add a reference to Microsoft.CSharp.dll to the project (probably right-click on the project, 'Add Reference', find Microsoft.CSharp).

My guess is that the project you're using was created with a pre-release version of VS, and is missing the proper references.

Frida

Hi, this is exactly what I have: Framework 4.0, and as you see in the image Microsoft.CSharp is already in my references; that's the reason why I don't understand this error. Microsoft.CSharp is added in the reference and it stills saying that I cannot compile without it… Do you think other assemblies should be also added to make it work? – Genna

Oh, I missed that in the image. I'm not sure what's going on then. It might be a MonoDevelop issue. – Frida

You can find my solution bellow. I think I was adding the wrong assemblies from the from platform. Got no such problems with IronPython 2.7.0 so I switched. – Genna