How do i get a cross threaded call using the paralell extensions to update progress

[edinwoking]

Hi

I have been struggling to get a toolbar to update its progress information from an event raised ina parallel for loop. I have tried using delegates to get it to work but it just hangs after about the iteration.

The code that replicates the problem is below. It s just a windows form with a toolstrip and a toolstripprogressbar with a button to start the test.

I am relativly new to multi threading but in all the examples i have tried from various sources on the net I cannot get this to work.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;
 
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        delegate void ProgressDelegate(int progress);
 
 
        public Form1()
        {
            InitializeComponent();
            // A nasty HACK but the delegate method invocation seems to be recursive and not work.
            //Control.CheckForIllegalCrossThreadCalls = false; 
 
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            Class1 test = new Class1();
            test.progress += new EventHandler<ProgressArgs>(test_progress);
            test.DoWork();
            this.toolStripProgressBar1.Value = 0; // reset
 
        }
 
        void test_progress(object sender, ProgressArgs e)
        {
            //if (e.ProgressValue>this.toolStripProgressBar1.Value)
            //    this.toolStripProgressBar1.Value = e.ProgressValue;
 
            SetProgress(e.ProgressValue);
        }
 
        public void SetProgress(int progress)
        {
            if (this.InvokeRequired)
            {
                ProgressDelegate d = new ProgressDelegate(SetProgress);
                this.Invoke(d, new object[] { progress });
            }
            else
            {
                this.toolStripProgressBar1.Value = progress;
            }
 
        }
 
    }
 
    class Class1
    {
        public event EventHandler<ProgressArgs> progress;
 
        public void DoWork()
        {
            Parallel.For(0, 100, i =>
            {
                Thread.Sleep(25);
                this.progress(this, new ProgressArgs(i));
            });
        }
    }
 
    class ProgressArgs : EventArgs
    {
        int _progressvalue = 0;
 
        public ProgressArgs(int progressvalue)
        {
            _progressvalue = progressvalue;
        }
 
        public int ProgressValue
        {
            get
            {
                return _progressvalue;
            }
            set
            {
                _progressvalue = value;
            }
 
        }
    }
}

Best Regards

[TRScheel]

After looking up Parallel for quite a while (I have never seen that call before) I came across a few different resources.

It seems Parallel has been updated and is now part of LINQ. In addition I had read that it actually only ran on one thread, per this article here.

My guess is that you call Thread.Sleep on the same thread over and over again until it hangs.