Windows Phone Back KeyPress + MessageBox 使应用程序在没有选择的情况下崩溃 [英] Windows Phone Back KeyPress + MessageBox crashes the app without Selection

问题描述

我有一个奇怪的问题在后面的代码中覆盖 BackkeyPress 函数，在函数内部我有一个简单的消息框可以返回或取消导航(留在当前页面)，当没有选择(确定或取消)并且 Messagebox 是打开很长时间，应用程序崩溃，当我尝试调试时，不会抛出任何异常并且应用程序保持状态，除非按下确定或取消，但在正常运行(没有调试器)时，崩溃很明显.

I have a strange issue overriding BackkeyPress Function in code behind, inside the function i have a simple message box to Go back or cancel navigation ( stay in current page ), when no choice is made (ok or cancel ) and Messagebox is open for long time, Application crashes, when i try to debug, no exception is thrown and App remains in the state unless OK or cancel is pressed , but on Normal run ( without debugger ) the crash is apparent.

    protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
    {

        string caption = "exit?";
        string message = "Do you still want to exit?";
        e.Cancel = MessageBoxResult.Cancel == MessageBox.Show(message, caption,           
        MessageBoxButton.OKCancel);

        base.OnBackKeyPress(e);

    }

推荐答案

http://msdn.microsoft.com/en-US/library/windowsphone/develop/jj206947(v=vs.105).aspx

在 Windows Phone 8 中，如果您调用 Show inOnBackKeyPress(CancelEventArgs) 或 BackKeyPress 的处理程序事件，应用程序将退出.

In Windows Phone 8, if you call Show in OnBackKeyPress(CancelEventArgs) or a handler for the BackKeyPress event, the app will exit.

您可以通过在不同线程上调用 Show 来解决此问题，如在以下步骤中描述.覆盖 BackKeyPress 或创建一个BackKeyPress 事件的处理程序.将 Cancel 设置为 true 以取消后退键按下动作.调度一个方法，显示消息框.如果用户选择离开应用程序，调用 Terminate()，否则，什么都不做.

You can work around this by calling Show on a different thread, as described in the following steps. Override BackKeyPress or create a handler for the BackKeyPress event. Set the Cancel to true to cancel the back key press action. Dispatch a method that shows the MessageBox. If the user chooses to leave the app, call Terminate(), otherwise, do nothing.

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