C# Using Assembly to call a method within a DLL

Question

I have been reading a lot about this - I feel like I'm very close to the answer. I am simply looking to call a method from within a dll file that I have created.

For example purposes:

My DLL File:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ExampleDLL
{
    class Program
    {
        static void Main(string[] args)
        {
            System.Windows.Forms.MessageBox.Show(args[0]);
        }

        public void myVoid(string foo)
        {
            System.Windows.Forms.MessageBox.Show(foo);
        }
    }
}

My Application:

string filename = @"C:\Test.dll";
    Assembly SampleAssembly;
    SampleAssembly = Assembly.LoadFrom(filename);
    // Obtain a reference to a method known to exist in assembly.
    MethodInfo Method = SampleAssembly.GetTypes()[0].GetMethod("myVoid");
    // Obtain a reference to the parameters collection of the MethodInfo instance.

All credits go to SO user 'woohoo' for the above snippet How to call a Managed DLL File in C#?

Now, though, I would like to be able to not only reference my Dll (and the methods inside it) but properly call the methods inside it (in this case I would like to call method 'myVoid').

Might anyone have any suggestions for me?

Thank you,

Evan

Solution

//Assembly1.dll
using System;
using System.Reflection;

namespace TestAssembly
{
    public class Main
    {
        public void Run(string parameters)
        {
            // Do something... 
        }
        public void TestNoParameters()
        {
            // Do something... 
        }
    }
}

//Executing Assembly.exe
public class TestReflection
{
    public void Test(string methodName)
    {
        Assembly assembly = Assembly.LoadFile("...Assembly1.dll");
        Type type = assembly.GetType("TestAssembly.Main");
        if (type != null)
        {
            MethodInfo methodInfo = type.GetMethod(methodName);
            if (methodInfo != null)
            {
                object result = null;
                ParameterInfo[] parameters = methodInfo.GetParameters();
                object classInstance = Activator.CreateInstance(type, null);
                if (parameters.Length == 0)
                {
                    result = methodInfo.Invoke(classInstance, null);
                }
                else
                {
                    object[] parametersArray = new object[] { "Hello" };

                    result = methodInfo.Invoke(classInstance, parametersArray);
                }
            }
        }
    }
}