工作与Windows Phone 8.1返回键按事件

本文关键字：返回 事件 Windows Phone 工作 | 更新日期: 2023-09-27 18:12:13

我正在我的Windows Phone 8.1应用程序上工作。我想在用户按下后退键时显示消息。我知道密码，但有点不对劲。Visual Studio显示MessageBox, MessageBoxResult下面的红线

如何在Windows Phone 8.1中显示消息?我认为这在WP7操作系统之后有所改变。

下面是我的代码示例。

public MainPage()
    {
        this.InitializeComponent();
        progRing.IsActive = true;
        Window.Current.SizeChanged += Current_SizeChanged;
        Windows.Phone.UI.Input.HardwareButtons.BackPressed += HardwareButtons_BackPressed;
        this.NavigationCacheMode = NavigationCacheMode.Required;
    }
    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
    }
    private void HardwareButtons_BackPressed(object sender, Windows.Phone.UI.Input.BackPressedEventArgs e)
    {
    }
    protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
    {
        string caption = "Stop music and exit?";
        string message = "If you want to continue listen music while doing other stuff, please use Home key instead of Back key. Do you still want to exit?";
        e.Cancel = MessageBoxResult.Cancel == MessageBox.Show(message, caption, MessageBoxButton.OKCancel);
        base.OnBackKeyPress(e);
    }

工作与Windows Phone 8.1返回键按事件

根据Windows.Phone.UI.Input命名空间判断，您的目标是基于WinRT XAML的应用程序，而不是Silverlight WP8.1在WinRT中没有MessageBox.Show()方法你必须使用MessageDialog类优点是你可以自定义对话框上按钮的名称，而且这个过程现在是异步的，这意味着当消息对话框显示时，它不会阻止你的应用程序运行

using Windows.UI.Popups;
...
MessageDialog dialogbox= new MessageDialog("Your message content", "title");
await dialogbox.ShowAsync();

JayDev的答案是完整正确的

JayDev回答的一个问题是WinRT中没有"override onBackKeyPress"。这是你必须做的:

using Windows.Phone.UI.Input
...
protected override void OnNavigatedTo(NavigationEventArgs e)
        {
        //This should be written here rather than the contructor
        HardwareButtons.BackPressed += HardwareButtons_BackPressed;
        }
void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
        {
        //This is where all your 'override backkey' code goes
        //You can put message dialog and/or cancel the back key using e.Handled = true;
        }
protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
        {
        //remove the handler before you leave!
        HardwareButtons.BackPressed -= HardwareButtons_BackPressed;
        }

您需要使用MessageDialog而不是MessageBox。即

        MessageDialog message = new MessageDialog("my message");
        message.ShowAsync();

MessageDialog在Windows.UI.Popups命名空间中。

具体到您可以使用的场景。

protected async override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
    string caption = "Stop music and exit?";
    string message = "If you want to continue listen music while doing other stuff, please use Home key instead of Back key. Do you still want to exit?";
    MessageDialog msgDialog = new MessageDialog(message, caption);
    //OK Button
    UICommand okBtn = new UICommand("OK");
    msgDialog.Commands.Add(okBtn);
    //Cancel Button
     UICommand cancelBtn = new UICommand("Cancel");
     cancelBtn.Invoked = (s) => { e.Cancel = true; };
     msgDialog.Commands.Add(cancelBtn);
       //Show message
     await msgDialog.ShowAsync();
    base.OnBackKeyPress(e);
}

试试这个:

    MessageBoxResult res= MessageBox.Show(message,caption, MessageBoxButton.OKCancel);
    if (res == MessageBoxResult.OK)
    {
        //Do Action
    }
    else
    {
        //Do Action
    }
相关文章：