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Reflection pass by ref abnormal behavior

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Sri Vobilisetti (VIP)

hi,
I am trying to call a method from a .net class dynamically and I am passing
a string reference to the method. Below is a sample of what I am doing.
Somehow the value of the parameter passed is not being updated. The wierd
thing is that if I change the variable type to Integer, it works.
====================================================
using System;
using System.Reflection;
using System.Collections;

namespace ReflectionTest
{
public class M
{
    public void Method(ref string x)
    {
        x ="Changed value";
    }
    [STAThread]
    public static void Main()
    {
    Hashtable h = new Hashtable();
    h.Add("ABC", "Initial value"); //Set initial value
        Type t = typeof(M);
        M m = (M)Activator.CreateInstance(t);//Create instance of M
        Type [] p = new Type[1];
        p[0] = Type.GetType("System.String&");//typeof(ref string)
        MethodInfo mi = t.GetMethod("Method", p);//Get the method
        Object [] ps = {h["ABC"]}; //Create param array
        mi.Invoke(m,ps);
        Console.WriteLine(h["ABC"]); //**output is "Initial value"
//**But I expect it to be "Changed value"
    }

}
}
====================================================

But if I change the variable type to Int, the value in the hashtable gets
updated. See sample below.
====================================================
using System;
using System.Reflection;
using System.Collections;

namespace ReflectionTest
{
public class M
{
    public void Method(ref int x)
    {
        x =500;
    }
    [STAThread]
    public static void Main()
    {
    Hashtable h = new Hashtable();
    h.Add("ABC", 5); //Set initial value as 5
        Type t = typeof(M);
        M m = (M)Activator.CreateInstance(t);// Create instance of M
        Type [] p = new Type[1];
        p[0] = Type.GetType("System.Int32&");// typeof(ref int)
        MethodInfo mi = t.GetMethod("Method", p);// Get the method
        Object [] ps = {h["ABC"]}; // Create param array
        mi.Invoke(m,ps);
        Console.WriteLine(h["ABC"]); //*****output is 500
    }

}
}
====================================================

Is this a kind of bug? Any ideas on getting this to work with strings.

Thank you for your time.

Regards,
Sri Vobilisetti

Reply to this message...

Andriy Gnennyy

Check ps[] after Invoke. The ps[0] = = "Changed value".

--
Andriy Gnennyy
pulsar2003@{no-spam}email.ru (Please remove {no-spam} for reply)
X-Unity Test Studio
http://x-unity.miik.com.ua/teststudio.aspx

"Sri Vobilisetti" <Click here to reveal e-mail address> wrote in
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Reply to this message...

Sri Vobilisetti (VIP)

Thank you for your help.

"Andriy Gnennyy" wrote:

[Original message clipped]

Reply to this message...

	System.Activator
	System.Collections.Hashtable
	System.Console
	System.Int32
	System.Reflection.MethodInfo
	System.String
	System.Type

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