Hi,

We try callback C# method from C++ DLL using delegate, using delegate
without argument works fine for me however the
CallBackFunctionWithParameter which call delegate with parameter crash
the application after being called .
Any suggestion will help and really appreaciated

Thanks

Budi

Here is the code :

In C#
=======================================================================
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

namespace FunctionCallbacks
{
    public class Form1 : System.Windows.Forms.Form
    {
        delegate void delegateMethod ();
        delegate void delegateMethodWithParameter(int i);
        private System.Windows.Forms.Button button1;

        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.Container components = null;

        [DllImport("..\\..\\..\\C++\\Debug\\C++.dll")]
        private static extern void CallBackFunction (delegateMethod method);

        [DllImport("..\\..\\..\\C++\\Debug\\C++.dll")]
        private static extern void CallBackFunctionWithParameter
(delegateMethodWithParameter method);

        public Form1()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();
        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            //
            // button1
            //
            this.button1.Location = new System.Drawing.Point(88, 120);
            this.button1.Name = "button1";
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.Click += new System.EventHandler(this.button1_Click);
            //
            // Form1
            //
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(292, 266);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);

        }
        #endregion

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.Run(new Form1());
        }

        private void Form1_Load(object sender, System.EventArgs e)
        {
        }

        private void button1_Click(object sender, System.EventArgs e)
        {
            delegateMethod d = new delegateMethod(PrintMessage);
            delegateMethodWithParameter f = new
delegateMethodWithParameter(PrintMessageWithParameter);
            CallBackFunction (d);                //in C++ dll
            CallBackFunctionWithParameter(f);                //in C++ dll
        }

        public void PrintMessage (   )
        {
            MessageBox.Show ("Hello");
        }

        public void PrintMessageWithParameter(int i)
        {
            MessageBox.Show(i.ToString());
        }
    }
}

=======================================================================

In Win32 DLL
=======================================================================.
.
.
//takes a function pointer as an argument
extern "C" __declspec(dllexport) void CallBackFunction
(void(*callFunction()))
{
    callFunction ();        //call 'PrintMessage()' method in C#
}

//takes a function pointer as an argument
extern "C" __declspec(dllexport) void CallBackFunctionWithParameter
(void (*callFunctionWithParameter) (int i))
{
    callFunctionWithParameter(111); // call 'PrintMessage()' method
                         // in C#
}
.
.
.