Xamarin 当我选择“否”时，显示警报消息显示两次为什么？选择“否”时，如何仅显示一次警报？

公共异步无效clearswitchHandle\u Toggledobject发送方， 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;

        }

    }

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尝试锁定此异步方法，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;
    }