WPF强制使用Dipatcher

Question

我只需要显示自定义控制（带有旋转指针的时钟）GUI更新并以此取代鼠标光标，问题是，如果我写：

Me.gridScreen.Visibility = Visibility.Visible 
' some operations that takes about 1 second 
Me.gridScreen.Visibility = Visibility.Hidden 
(gridScreen is the grid that contains the user-control) 

很显然，我什么也看不到，因为UI的更新发生在过程的最后。我尝试过Me.UpdateLayout（），但它不起作用。

我已经tryed使用在许多方式dispacker但没有，工程:-(

这就是我丢失的尝试：

（uCurClock是用户控件，gridScreen放置在顶层网格在窗口中，用trasparent背景中，包含该用户控件）

Private Sub showClock() 
    Dim thread = New System.Threading.Thread(AddressOf showClockIntermediate) 
    thread.Start() 
End Sub 

Private Sub hideClock() 
    Dim thread = New System.Threading.Thread(AddressOf hideClockIntermediate) 
    thread.Start() 
End Sub 

Private Sub showClockIntermediate() 
    Me.Dispatcher.BeginInvoke(DispatcherPriority.Normal, _ 
     New Action(AddressOf showClockFinale)) 
End Sub 

Private Sub hideClockIntermediate() 
    Me.Dispatcher.BeginInvoke(DispatcherPriority.Normal, _ 
     New Action(AddressOf hideClockFinale)) 
End Sub 

Private Sub showClockFinale() 
    Dim pt As Point = Mouse.GetPosition(Nothing) 
    Me.uCurClock.Margin = New Thickness(pt.X - 9, pt.Y - 9, 0, 0) 
    Me.gridScreen.Visibility = Visibility.Visible 
    Me.Cursor = Cursors.None 
    Me.UpdateLayout() 
End Sub 

Private Sub hideClockFinale() 
    Me.gridScreen.Visibility = Visibility.Hidden 
    Me.Cursor = Cursors.Arrow 
    Me.UpdateLayout() 
End Sub 

Private Sub u_MouseMove(ByVal sender As System.Object, _ 
    ByVal e As MouseEventArgs) Handles gridScreen.MouseMove 

    Dim pt As Point = e.GetPosition(Nothing) 
    Me.uCurClock.Margin = New Thickness(pt.X - 9, pt.Y - 9, 0, 0) 

    e.Handled = True 
End Sub 

Private Sub u_MouseEnter(ByVal sender As System.Object, _ 
    ByVal e As MouseEventArgs) Handles gridScreen.MouseEnter 

    Me.uCurClock.Visibility = Visibility.Visible 

    e.Handled = True 
End Sub 

Private Sub u_MouseLeave(ByVal sender As System.Object, _ 
    ByVal e As MouseEventArgs) Handles gridScreen.MouseLeave 

    Me.uCurClock.Visibility = Visibility.Hidden 

    e.Handled = True 
End Sub 

PIleggi

Answer 1

的问题不是用MES的组合物做圣人在调度员上执行，这就是你在调度员上执行长时间运行的工作。您必须确保长时间运行/可能的阻塞操作在后台线程上执行。最简单的方法是使用BackgroundWorker组件。

借口C＃：

var backgroundWorker = new BackgroundWorker(); 

backgroundWorker.DoWork += delegate 
{ 
    // long running work goes here 
}; 
backgroundWorker.RunWorkerCompleted += delegate 
{ 
    // change cursor back to normal here 
}; 

// change cursor to busy here 

// kick off the background task 
backgroundWorker.RunWorkerAsync();