按钮事件Xamarin.Forms上的确认对话框

Question

我在Xamarin.Forms应用程序中被困在一点

在后退按钮按下我想要询问用户是否确实要退出,"OnBackButtonPressed"我想显示警告对话框并继续作为用户响应.

但是"OnBackButtonPressed"不是Async我不能写等待DisplayAlert ...请指导我如何实现这个功能？

我使用ContentPage作为NavigationPage的根页面

    public class frmHome : ContentPage

这是代码:

protected override bool OnBackButtonPressed()
{
    var result = await  this.DisplayAlert("Alert!", "Do you really want to exit?", "Yes", "No");

    if (result)
        {
            //user wants to exit
            //Terminate application
        }
        else
        {
            //Dont do anything
        }
}

Answer 1

    protected override bool OnBackButtonPressed()
    {
        Device.BeginInvokeOnMainThread(async() => {
            var result = await this.DisplayAlert("Alert!", "Do you really want to exit?", "Yes", "No");
            if (result) await this.Navigation.PopAsync(); // or anything else
        });

        return true;
    }

Answer 2

这是对我有用的代码

protected override bool OnBackButtonPressed()
    {
        Device.BeginInvokeOnMainThread(async () =>
        {
            var result = await this.DisplayAlert("Alert!", "Do you really want to exit?", "Yes", "No");

            if (result)
            {
                System.Diagnostics.Process.GetCurrentProcess().CloseMainWindow(); // Or anything else
            }
        });
        return true;
    }