How to dynamically call a class' method in .NET?

Question

Hi, How to pass a class and a method name as strings and invoke that class' method?

Like

void caller(string myclass, string mymethod){
    // call myclass.mymethod();
}

Thanks

Answer 1

You will want to use reflection.

Here is a simple example:

using System;
using System.Reflection;

class Program
{
    static void Main()
    {
     caller("Foo", "Bar");
    }

    static void caller(String myclass, String mymethod)
    {
     // Get a type from the string 
     Type type = Type.GetType(myclass);
     // Create an instance of that type
     Object obj = Activator.CreateInstance(type);
     // Retrieve the method you are looking for
     MethodInfo methodInfo = type.GetMethod(mymethod);
     // Invoke the method on the instance we created above
     methodInfo.Invoke(obj, null);
    }
}

class Foo
{
    public void Bar()
    {
     Console.WriteLine("Bar");
    }
}

Now this is a very simple example, devoid of error checking and also ignores bigger problems like what to do if the type lives in another assembly but I think this should set you on the right track.

Answer 2

Something like this:

public object InvokeByName(string typeName, string methodName)
{
    Type callType = Type.GetType(typeName);

    return callType.InvokeMember(methodName, 
                    BindingFlags.InvokeMethod | BindingFlags.Public, 
                    null, null, null);
}

You should modify the binding flags according to the method you wish to call, as well as check the Type.InvokeMember method in msdn to be certain of what you really need.

Answer 3

What's your reason for doing this? More than likely you can do this without reflection, up to and including dynamic assembly loading.