Create and invoke a function in run time, C#

there is a way to create and invoke a function in run time? for instance, how could I do to invoke this function?

    string function = @"public void Test(int num1, int num2)
        {
            int sum = num1 + num2;
            MessageBox.Show(sum.ToString());
        }";

        System.Reflection.MethodInfo method = null; // some code to create a method info from the string function
        method.Invoke(this, new object[] { 10, 20 });

All I could find were samples of System.Reflection.Emit.DynamicMethod, but none use a function in a string