如何在应用程序终止然后使用 Visual Studio 以 xamarin 形式启动时进行调试

Question

I am developing a Xamarin Forms app using Visual studio.

I want to test this scenario:

1. I open an app
2. Do some operations
3. Terminate the app and launch the application
4. Now I want to hit a break point in Visual Studio

How to achieve this? Mainly I would like to test these events - Suspended, Shutdown and Resume.

Can someone please help me out?

Answer 1

It has to do with Xamarin. Forms Lifecycle Methods : Put your breakpoints in following methods inside the App.xaml.cs class:

OnStart - Called when the application starts.

OnSleep - Called each time the application goes to the background.

OnResume - Called when the application is resumed, after being sent to the background.

Note that there is no method for application termination. Under normal circumstances (ie. not a crash) application termination will happen from the OnSleep state, without any additional notifications to your code.

To observe when these methods are called, implement a WriteLine call in each (as shown below) and test on each platform.

protected override void OnStart()
{
    Debug.WriteLine ("OnStart");
}
protected override void OnSleep()
{
    Debug.WriteLine ("OnSleep");
}
protected override void OnResume()
{
    Debug.WriteLine ("OnResume");
}