I can update UI from background thread, why?

Question

Everybody knows, that updating UI from background thread is not allowed (or not?)

I did a little experiment. Here is a piece of code:

var thread = ne         


        

Answer 1

Like varocarbas says any component you put into your designer will throw Cross thread exception.

to access between thread you need to use invke, beginInvoke.

try to run

BackgroundWorker bw = new BackgroundWorker();
bw.DoWork += (s1,e1) => 
{
    textBoxt1.Text = "foo";  // Exception here
} 
bw.RunWorkerCompleted += (1s, e1) =>
{
    textBoxt1.Text = "foo";  // No exception here off UI thread
}
bw.RunWorkerAsync();

instead replace

bw.DoWork += (s1,e1) => 
{
    this.Invoke((MethodInvoker) delegate 
   {
        textBoxt1.Text = message;
   });  // No Exception now
}