Dynamic load .NET dll files (Creating a plug-in system) – C#

Finally I found some spare time to write an article on my (this) blog.

In the last days I needed to write a plug-in system for one of my projects. I managed to write it in C# and decided to share it on my blog. It’s really simple to create as you will see:
//This is a C# Console Application Project. The code was written with .NET Framework 2.0

using System;
using System.Reflection;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
if (args.Length >= 1)
{
object[] s;
if (args.Length >= 2)
{
s = new object[args.Length - 1];
Array.Copy(args, 1, s, 0, args.Length – 1);
}
else
s = new object[] { };
Console.WriteLine(“Loading dll…”);
try{
Console.WriteLine(LoadDllMethod(“Namespace1.Class1″, “Method1″, args[0], s));
Console.WriteLine(“Dll method called!”);
}catch(Exception ex){Console.WriteLine(“Error:” + ex.ToString());}
}
Console.ReadLine();
}

static string LoadDllMethod(string title_class, string title_void, string path, object[] parameters)
{
Assembly u = Assembly.LoadFile(path);
Type t = u.GetType(title_class);
if (t != null)
{
MethodInfo m = t.GetMethod(title_void);
if (m != null)
{
if (parameters.Length >= 1)
{
object[] myparam = new object[1];
myparam[0] = parameters;
return (string)m.Invoke(null, myparam);
}
else
return (string)m.Invoke(null, null);
}
}
Exception ex = new Exception(“method/class not found”);
throw ex;
}
}
}
Off course you must change the code for specified type methods.

If you have 2 parameters for Method1 you must define the myparam Object as 2 length (object[] myparam=new myparams[2]), also you can get some exceptions if the Method1’s parameters are not objects so you must change myparam type.

Please take into account that the dll-s written in a .NET version major to the one the “invoker” was written in will not load.