xamarin - 当我选择否时，显示警报消息显示两次，为什么？当我选择否时，如何只显示一次警报？

Question

公共异步无效 clearswitchHandle_Toggled（对象发件人，Xamarin.Forms.ToggledEventArgs e）{

        var yesSelected = await DisplayAlert("WARNING!!!", "Are you sure you want to CLEAR DATA entered", "YES", "NO");
        if (yesSelected == true)
        {
            clearButton.IsEnabled = true;
        }

        else 
        {
            clearSwitch.IsToggled = false;

        }

    }

标签： xamarin

Answer 1

尝试锁定这个异步方法，它可能会被多次调用：

private bool lockAlert;
public async void Handle_Toggled(object sender, Xamarin.Forms.ToggledEventArgs e) 
{
        if (lockAlert) return;
        lockAlert=true;

        var ok = await DisplayAlert("WARNING!!!", "Are you sure you want to CLEAR DATA entered", "YES", "NO");
        if (ok)
        {
            clearButton.IsEnabled = true;
        }
        else 
        {
            clearSwitch.IsToggled = false;
        }

        lockAlert=false;
    }