WPF ComboBox下拉部分出现在错误的地方 [英] WPF ComboBox DropDown part appears in the wrong place

问题描述

我在XAML窗口放了几个ComboBoxes。当我展开任何一个，DropDown部分出现在屏幕的左上角。

I put several ComboBoxes on a XAML window. When I expand any of them, the DropDown part appears on the upper left corner of the screen.

我使用Visual Studio 2008 C＃Express。我不使用Visual Studio 2008（试用版），但我使用相同的FrameWork（3.5）。

I use Visual Studio 2008 C# Express. I don't remember this phenomenon when I used Visual Studio 2008 (Trial Version), though I use the same FrameWork (3.5).

推荐答案

这似乎是WPF中的一个错误。在我的情况下，我试图在另一个窗口的Loaded事件中打开一个窗口。为了解决这个问题，我设置一个定时器来触发，然后使用一个代理打开窗口（无法打开定时器事件中的窗口，因为打开窗口的调用线程必须是STA）。

This appears to be a bug in WPF. In my case, I was trying to open a window in the Loaded event of another window. To get around this, I set a timer up to fire, then used a delegate to open the window (cannot open the window in a timer event because the calling thread that opens a window must be STA).

编辑 - 计时器不是必需的 - 没有看到上面的答案只是排队它在调度程序...

Edit - timer isn't necessary - didn't see the answer above just queue it on the dispatcher...

private delegate void DelegateOpenWindow();
private DelegateOpenWindow m_DelegateOpenWindow;
private Timer loginTimer = new Timer(200);

private void MainWindow1_Loaded(object sender, RoutedEventArgs e)
{
        // create delegate used for asynchronous call
        m_DelegateOpenWindow= new DelegateOpenWindow(this.OpenWindow);
        // start a timer to fire off the open window.
        loginTimer.Elapsed += loginTimer_Elapsed;
        loginTimer.Enabled = true;
}

void loginTimer_Elapsed(object sender, ElapsedEventArgs e)
{
        loginTimer.Enabled = false;
        this.Dispatcher.BeginInvoke(m_DelegateOpenWindow);

}

void OpenWindow()
{
        MyWindow w = new MyWindow();
        w.Owner = this;
        w.ShowDialog();
}

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