Background Worker freezes UI in c#

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HI..

I'm using background-worker but still it freeze UI in windows Application.

C#

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    try
    {
        Action DoCrossThreadUIWork = ()
        {
            CreateDataGridView();   // Method Create dataGridView and Handling Some GridView Events (e.g dataGridView1_Paint)

            DayScheduleTable = clsSqlQueries.ExecuteQuery(clsSqlQueries.GetDaySchedule); // Read Table From DataBase
            FillDataGridView();   // Fill DataGridView
        };
        this.BeginInvoke(DoCrossThreadUIWork);
    }
    catch (Exception ex)
    {
        clsWriteLog.GetInstance().WriteErrorLog(clsPublicMethod.GetInstance().GetMethodName(), ex.Message);
    }
}



private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    progressBar1.Value = e.ProgressPercentage;
}

And Call background worker in Form_load Event As:

C#

if (!backgroundWorker1.IsBusy)
                  backgroundWorker1.RunWorkerAsync()

If have any idea please share..

Posted 9-Nov-14 20:31pm

Member 11055395

Updated 9-Nov-14 20:41pm

Garth J Lancaster

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Comments

dan!sh 10-Nov-14 1:40am

Why are you handling Paint event in another thread? This is not the purpose of a background worker. You might want to rethink your design.

Member 11055395 10-Nov-14 19:33pm

Paint event is runtime assigned to gridview inside method which handled in background worker. so is paint event not in the background thread ?

Kornfeld Eliyahu Peter 10-Nov-14 1:52am

As all UI is a separate thread, there is a major problem to handle UI elements from the thread of the BackgroundWorker...It will mix non UI related windows messages on the UI thread and that blocks UI related messages (UI related messages have the lowest priority in message queue)...

Sergey Alexandrovich Kryukov 10-Nov-14 2:39am

Not clear. You don't show what CreateDataGridView and FillDataGridView do. Most likely, they should also be invoked to UI thread.
—SA

Member 11055395 10-Nov-14 19:29pm

CreateDataGridView Method Add Column in the GridView and also Assing Runtime GridVirew Paint Event inside this method.
FillDataGridView Method adds Rows in the GridView.

Sergey Alexandrovich Kryukov 10-Nov-14 20:08pm

And who will invoke them? :-)
—SA

Philippe Mori 20-Nov-14 20:20pm

That code does not make much sense to me. Why from the DoWork Handler you would call BeginInvoke of almost all code?

You have to separate code that do background work from code that update UI. If you can wait until the data is loaded before updating the grid, then you can set data into background worker result and access it from Completed handler. Otherwise, you might use User parameter of ReportProgress to send partial result to the UI. Finally, you have to find a good compromise between updating the UI. As a rule of the thumb since a progress bar usually display % as an integer value, I often report progress when the percentage truncated to an integer changes (thus, it would make up to about 100 updates which is adequate for most cases).

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Redgum · Answer 1 · 2014-11-20T14:18:00

Right from the start, I think the reason it's hanging is because your progress bar is likely OWNED by another thread. Like others have stated, you might want to reconsider your design here.

A way to invoke updates to a GUI element made by another thread is to make an invoker delegate. The following code illustrates an update method to a label which is designed to display the current time.

Also, a matter of personal preference is that anonymous threads are like loose canons. They're great for executing some very simple, one-time operation. But if it's to continuously update a UI element, I'd advise against their use in this case.

private delegate void StatusCallbackString(string someText);
.
.
.

private void updateUITime(string time)
{
    if (lblTime.InvokeRequired)
    {
        StatusCallbackString sCB = new StatusCallbackString(updateUITime);
        this.BeginInvoke(sCB, new object[] { time });
        return;
    }

    lblTime.Text = time;
}

Meanwhile, in a background thread somewhere...

private void MyThreadedOperation()
{
    while(keepThreadAlive)
    {
        updateUITime(DateTime.Now.ToString());

        .
        .
        // Sleep nicely for 1 second...
        System.Threading.CurrentThread.Join(1000);
    }
}

Background Worker freezes UI in c#

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Background Worker freezes UI in c#

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