Question

private async void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
{
    var msg = new MessageDialog("Confirm Close");
    var okBtn = new UICommand("OK");
    var cancelBtn = new UICommand("Cancel");
    msg.Commands.Add(okBtn);
    msg.Commands.Add(cancelBtn);
    IUICommand result = await msg.ShowAsync();
}

主要问题是当按下后退按钮时，消息显示1-2秒，应用程序关闭。怎么办？

Answer 1

异步工作正常我认为，您没有将 e.Handeled 设置为 true ，这意味着会处理更多BackPressed事件并退出应用。试试这样：

private async void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
{
    e.Handled = true;
    var msg = new MessageDialog("Confirm Close");
    var okBtn = new UICommand("OK");
    var cancelBtn = new UICommand("Cancel");
    msg.Commands.Add(okBtn);
    msg.Commands.Add(cancelBtn);
    IUICommand result = await msg.ShowAsync();
}

还要记住，您的应用必须能够通过BackButton退出，因此上述代码必须以某种方式进行修改。

Answer 2

试试这段代码：

var messgeDialog = new MessageDialog("Are you sure you want to close", "Are you sure?");
                    messgeDialog.Commands.Add(new UICommand("Yes"));
                    messgeDialog.Commands.Add(new UICommand("No"));
                    messgeDialog.DefaultCommandIndex = 0;
                    messgeDialog.CancelCommandIndex = 1;
                    var result = await messgeDialog.ShowAsync();
                    if (result.Label.Equals("Yes"))
                    {
                    //Do something when a user pressed yes
                    }
                    else
                    {
                    //User pressed no
                    }

async无法按下Windows Phone 8.1的后退键

2 个答案: