Displaying Please Wait Window on a SeperateThread

Question

I have a method that exports the contents of my DataGrid to a CSV file. I\'m trying to display a Window that has an animation on it to ask

Answer 1

You need to move the creation of the window into the new Thread, use ShowDialog to make sure it blocks and close it via its own Dispatcher.

PleaseWaitWindow waitWindow = null;

var newWindowThread = new Thread(() =>
    {
        waitWindow = new PleaseWaitWindow();
        waitWindow.ShowDialog();
    }
);

newWindowThread.SetApartmentState(ApartmentState.STA);
newWindowThread.Start();

ExcelExport();

waitWindow.Dispatcher.BeginInvoke(new Action(() =>
{
    waitWindow.Close();
}));

Just make sure waitWindow is created before trying to close it, some kind of IPC barrier would be good here. For Example (quick and dirty):

PleaseWaitWindow waitWindow = null;
AutoResetEvent loaded = new AutoResetEvent(false);

var newWindowThread = new Thread(() =>
    {
        waitWindow = new PleaseWaitWindow();
        loaded.Set();
        waitWindow.ShowDialog();
    });

newWindowThread.SetApartmentState(ApartmentState.STA);
newWindowThread.Start();

ExcelExport();

loaded.WaitOne();

waitWindow.Dispatcher.BeginInvoke(new Action(() =>
{
    waitWindow.Close();
}));