Question

I have a for loop in my WPF. The textbox does not get updated until the loop has finished.

My code:

for (int i = 0; i < 10; i++)
{
    Thread.Sleep(1500);
    // MessageBox.Show(i.ToString());
    updateTextBox(i);
}

Update function:

private void updateTextBox(int i)
{
    // MessageBox.Show("reached here:" + i.ToString());
    txtExecLog.AppendText("\n" + i.ToString());
 }

If I uncomment the messagebox text, it updates one by one, otherwise it updates after 15 secs (1.5*10) the textbox with all the values.

Answer 1

You’re blocking the UI thread when you sleep. You mustn’t do that – nothing can be processed on the UI thread while you’re sleeping. If you want to take an action periodically (on the UI thread) use DispatcherTimer.