Creating a WPF Window from WinForms BackgroundWorker

Question

I have a WPF dll that contains several Window classes and provides methods that display these windows.

I also have a separate WinForms project that calls one of these methods in a WPF project inside the DoWork method of the BackgroundWorker component.

In the line of code creating the WPF window, I get the following runtime error:

The calling thread must be an STA, because it requires many user interface components.

A google search allows me this discussion . (It turns out that John Skeet answers questions on other sites in addition to stack overflows!) He contacted this article , which says

The BackgroundWorker component works well with WPF ...

This article also mentions the use of the DispatcherObject class, but I don’t understand how to do this, and I would rather just continue to use my BackgroundWorker component.

As a test case, I cited the following code to reproduce the error. In the WPF class library, here is the code in Window1.xaml.vb

Partial Public Class Window1

    Public Shared Function ShowMe() As Boolean?
        Dim w = New Window1 'Error appears on this line.
        Return w.ShowDialog()
    End Function

End Class

In a WinForms application, here is the code in Form1.vb

Imports System.ComponentModel

Public Class Form1

    Private WithEvents worker As BackgroundWorker
    Private Sub doWord(ByVal sender As Object, ByVal e As DoWorkEventArgs) Handles worker.DoWork
        WpfLibrary.Window1.ShowMe()
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        worker = New BackgroundWorker
        worker.RunWorkerAsync()
    End Sub
End Class

Even when the BackgroundWorker component is placed in Window1.xaml.vb, the same error occurs. So this article is wrong and I can not use BackgroundWorker with WPF? Or is there something else I need to do to make it work?

If BackgroundWorker will not work, how can I replace the code in Form1.vb above to use the dispatcher instead?

Answer 1

WPF, .

, - , winform WPF, BackgroundWorker DoWork .

BackgroundWorker, BackgroundWorker, RunWorkerCompleted.

, , , , , .

Answer 2

, STA, Thread.Join(), . ( , ).

#:

Thread workerThread = new Thread(ShowMyWindow);
workerThread.SetApartmentState(ApartmentState.STA);
workerThread.Start();
workerThread.Join();

:

private void ShowMyWindow()
{
    WpfLibrary.Window1.ShowMe()
}