How to use reflection to call a method and pass parameters whose types are unknown at compile time?
- by MandoMando
I'd like to call methods of a class dynamically with parameter values that are "parsed" from a string input.
For example:
I'd like to call the following program with these commands:
c:myprog.exe MethodA System.Int32 777
c:myprog.exe MethodA System.float 23.17
c:myprog.exe MethodB System.Int32& 777
c:myprog.exe MethodC System.Int32 777 System.String ThisCanBeDone
static void Main(string[] args)
{
ClassA aa = new ClassA();
System.Type[] types = new Type[args.Length / 2];
object[] ParamArray = new object[types.Length];
for (int i=0; i < types.Length; i++)
{
types[i] = System.Type.GetType(args[i*2 + 1]);
// LINE_X: this will obviously cause runtime error invalid type/casting
ParamArray[i] = args[i*2 + 2];
MethodInfo callInfo = aa.GetType().GetMethod(args[0],types);
callInfo.Invoke(aa, ParamArray);
}
// In a non-changeable classlib:
public class ClassA
{
public void MethodA(int i) { Console.Write(i.ToString()); }
public void MethodA(float f) { Console.Write(f.ToString()); }
public void MethodB(ref int i) { Console.Write(i.ToString()); i++; }
public void MethodC(int i, string s) { Console.Write(s + i.ToString()); }
public void MethodA(object o) { Console.Write("Argg! Type Trapped!"); }
}
"LINE_X" in the above code is the sticky part. For one, I have no idea how to assign value to a int or a ref int parameter even after I create it using Activator.CreatInstance or something else. The typeConverter does come to mind, but then that requires an explicit compile type casting as well.
Am I looking at CLR with JavaScript glasses or there is way to do this?
