dotnetbrowser Calling .NET from JavaScript - ThreadProblem

Question

[dotnetbrowser] Calling .NET from JavaScript - ThreadProblem

i am using vb net , vs 2017 and WPF, no mvvm.

My Wpf Mainwindow contains a dotnetbrowser-Webbrowser control (evaluation only). Looks this way:

            <wpf:WPFBrowserView x:Name="WebBrowser1" Background="Transparent"  Panel.ZIndex="1110"  
                                Margin="-5,-5,0,0"   Grid.ColumnSpan="2" 
                        BrowserType="LIGHTWEIGHT"           VerticalAlignment="Top" HorizontalAlignment="Left"
                                 Width="300" Height="300" >
                <wpf:WPFBrowserView.Preferences>
                    <DotNetBrowser:BrowserPreferences TransparentBackground="True"/>
                </wpf:WPFBrowserView.Preferences>
            </wpf:WPFBrowserView>

I defined an event like this:

         AddHandler WebBrowser1.Browser.ScriptContextCreated,
                    Sub(sender As Object, e As ScriptContextEventArgs)
                        Dim value As JSValue = WebBrowser1.Browser.ExecuteJavaScriptAndReturnValue("window")
                        value.AsObject().SetProperty("Account", New Account())
                    End Sub

The account looks like this:

    Public Class Account
        Public Sub Save(firstName As String, lastName As String)
            Try
                MessageBox.Show(firstName & " " & lastName)
                Dim freileg As New winLeg(firstName)
                freileg.Show()

            Catch ex As Exception
                l(ex.ToString())
            End Try
        End class

The messagebox shows firstname lastname correctly. But the new WPFWindow(winleg) smashes error:

Beim aufrufenden Thread muss es sich um einen STA-Thread handeln, da dies 
für viele Komponenten der Benutzeroberfläche erforderlich ist.

(engl: the calling thread must be STA cause its nessesary for many components of the UI)

I need the returned data within my main wpf-window thread. I am not really used to Threading (except Backgroundworker) so i am clueless. Any help would be appreciated.

Could you please try a solution based on `Dispatcher.Invoke` from https://dotnetbrowser.support.teamdev.com/support/solutions/articles/9000119178--cross-thread-operation-not-valid-control-accessed-from-a-thread-other-than-the-thread-it-was-create ? — Anna Dolbina, Oct 15 '18 at 08:30

score 0 · Accepted Answer · answered Oct 17 '18 at 07:09

Try to invoke your code using the application dispatcher. Here is the sample Account implementation:

Public Class Account
    Public Sub Save(firstName As String, lastName As String)
        Application.Current.Dispatcher.BeginInvoke(
                Sub()
                    Try
                        Dim window As New Window()
                        window.Title = firstName & " " & lastName
                        window.Width = 320
                        window.Height = 240
                        window.Show()
                    Catch ex As Exception
                        Debug.WriteLine(ex.ToString())
                    End Try
                End Sub)
    End Sub
End Class

dotnetbrowser Calling .NET from JavaScript - ThreadProblem

1 Answers1