Fixed: Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

I have just got an error Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on when I try to execute a C# windows application.

I have been trying to use multi-threading in my winform so that while it is perform a long process task my UI would get locked up. However after the task has finish and it try to update the UI I get an error.
 
System.Threading.Thread T1 = new System.Threading.Thread(FindFuncLoc);
T1.Start();
 
To get around this I use the mothodInvoker and put all my UI update inside this delegate and my problem is solved.
 
this.Invoke(newMethodInvoker(delegate                {
                    tlFuncLoc.DataSource = dtFuncLocsResult;
                    tlFuncLoc.Update();
                    lblMessage.Visible = false;
                    mpSearchProgress.Visible = false;
                }));
                return;
 
SAMPLE CODE:
 
private void btnSearch_Click(object sender, EventArgs e)
        {
            try
            {
                //Ensure that a Plant is select before the search can begin.
                if (cbPlant.ItemIndex >= 0)
                {
                    lblMessage.Visible = true;
                    mpSearchProgress.Visible = true;
 
                    System.Threading.Thread T1 = new System.Threading.Thread(FindFuncLoc);
                    T1.Start();
 
                    //FindFuncLoc();
                }
                else
                {
                    MessageBox.Show("Please select a plant to begin the search.");
                }
            }
            catch (Exception ex)
            {
                lblMessage.Visible = true;
                mpSearchProgress.Visible = true;
                MessageBox.Show(ex.Message);
            }
        }
 
        private void FindFuncLoc()
        {
 
            if (InvokeRequired)
            {
                // after we've done all the processing,  
 
                Database db = DatabaseFactory.CreateDatabase();
 
                DbCommand dbCommand = db.GetStoredProcCommand("prEntitySelectFilter");
                dbCommand.CommandTimeout = Program.Timeout;
                db.AddInParameter(dbCommand, "searchString", DbType.String, txtSearch.Text);
                db.AddInParameter(dbCommand, "rootEntityID", DbType.Int32, cbPlant.GetColumnValue("RootEntityID"));
                DataTable dtFuncLocsResult = db.ExecuteDataSet(dbCommand).Tables[0];
 
                this.Invoke(new MethodInvoker(delegate
                {
                    tlFuncLoc.DataSource = dtFuncLocsResult;
                    tlFuncLoc.Update();
                    lblMessage.Visible = false;
                    mpSearchProgress.Visible = false;
                }));
                return;
            }
 
        }
Like this Tip? 
Leave a comment if come across other solutions.

Comments (4)

|46.154.224.xxx |2011-05-31 00:47:53 YanuS

:D :D Thanks a lot.That was a huge problem for me.I searched the solution everywhere even MSDN. for me you are a hero :)))))

|90.204.7.xxx |2011-07-30 20:46:20 AK

Dude, your code simply rocks. Thanks a bunch. I had been running into the same error for sometime now. Working with UI threads is such a ball game...

|131.166.60.xxx |2012-01-03 14:14:25 Theis - Thank you!

Hey - thank you so much for this post - i had some real trouble getting this to work - after discovering your post i had my program running in no time!

Cheers
Theis

|SAdministrator |2012-01-03 16:11:26 admin

Theis - I am glad this helps.

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