How to implement Multi Threading in .NET

Hi

I actually have a few methods which use the progress bar on the form.

Let me show you quick.

        private delegate string[] InternalDelegate();
        private InternalDelegate intlDelg;

In My Constructor I have:

            ticker = new System.Timers.Timer();
            ticker.Elapsed += new ElapsedEventHandler(ticker_Elapsed);
            ticker.Interval = 250;
            intlDelg = new InternalDelegate(sqlInfo.EnumerateSQLServers);

then one of the form click events is as follows:

private void btnGetAllDataBases_Click(object sender, EventArgs e)
        {
             ticker.Start();
             intlDelg.BeginInvoke(new AsyncCallback(CallBackMethod), intlDelg);
             //There is other code which goes in here too.
         }

This here is the event that takes place with the intDelg.BeginInvoke()

private void CallBackMethod(IAsyncResult result)
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new AsyncDelegate(CallBackMethod), result);
            }
            else
            {
                try
                {
                    prgProgress.Value = prgProgress.Maximum;
                    switch (called)
                    {
                        case CallFor.SqlServerList:
                            string[] sqlServers = intlDelg.EndInvoke(result);
                            cmbSqlServers.Items.AddRange(sqlServers);
                            if (cmbSqlServers.Items.Count > 0)
                            {
                                cmbSqlServers.Sorted = true;
                                cmbSqlServers.SelectedIndex = 0;
                            }
                            this.Cursor = Cursors.Default;
                            btnLoadSqlServers.Enabled = true;
                            txtUserName.Select();
                            txtUserName.Focus();
                            break;
                        case CallFor.SqlDataBases:
                            string[] sqlDatabases = intlDelg.EndInvoke(result);
                            cmbAllDataBases.Items.AddRange(sqlDatabases);
                            if (cmbAllDataBases.Items.Count > 0)
                            {
                                cmbAllDataBases.Sorted = true;
                                cmbAllDataBases.SelectedIndex = 0;
                            }
                            this.Cursor = Cursors.Default;
                            btnGetAllDataBases.Enabled = true;
                            break;
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.ToString());
                }
                finally
                {
                    if (called == CallFor.SqlTables)
                    {
                      
                        this.Cursor = Cursors.Default;
                    }
                    prgProgress.Value = 0;
                    prgProgress.Refresh();
                    ticker.Stop();
                }
            }
        }

That then gets all the sql Servers on the network.

The ticker elapsed event is as follows:

void ticker_Elapsed(object sender, ElapsedEventArgs e)
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new TimerDelegate(ticker_Elapsed), sender, e);
            }
            else
            {
                if (prgProgress.Value == prgProgress.Maximum)
                {
                    prgProgress.Value = 0;
                }
                else
                {
                    prgProgress.Value += 20;
                }
            }
        }

This is where the progress bar gets updated.

So now, I have another button event which I want to do the same thing:

 private void btnOK_Click(object sender, EventArgs e)
        {
            err = "";
            if (ValidateDB())
            {
                if (ValidateForm())
                {
                    this.Cursor = Cursors.WaitCursor;
                    ticker.Start();
                    CommitData(); // This is the function which requires the data from the form again.
                    this.Cursor = Cursors.Default;
                }
                else
                {
                    MessageBox.Show(err);
                }
            }
            else
            {
                MessageBox.Show(err);
            }
        }

This is the function which then commits the data:

private void CommitData()
        {
            try
            {
                //The code which will go here is far to long to post here but it where
                //There is a for loop to iterate through the datagridview.
             }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
            finally
            {
                prgProgress.Value = 0;
                prgProgress.Refresh();
                ticker.Stop();
            }
        }

The above button click event is where I am trying to update my progress bar again, but it needs access to the main thread when I do it the with multiple threads. So what you are saying is, that if in that loop in the commit data function, If I call the Form.update(), it will work?

Thanks

I had this same issue and you do not need multiple threads to fix the problem. The solution is rather simple, everytime the progress bar is updated you need to call .Update() on the form displaying it. Try it it will work wonderfully.