xamarin - 后退按钮按下事件Xamarin.Forms上的确认对话框

Question

我被困在Xamarin.Forms应用程序中的某一处

我只想问一下返回按钮，请用户确认他是否真的想退出，
“ OnBackButtonPressed”我想显示“警报”对话框并作为用户响应进行。

但是“ OnBackButtonPressed”不是异步我无法编写等待DisplayAlert ...
请指导我如何实现此功能？

我正在使用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;
    }