Error CS0070: The event 'Game1.OnLoadingContent' can only appear on the left hand side of += or -= (except when used from within the type 'Game1')

Question

I get an error if I want to call OnLoadingContent from another class than Game1.cs. I have tried to call it from Options.cs:

game1.OnLoadingContent?.Invoke(this, new EventArgs());

Error CS0070: The event 'Game1.OnLoadingContent' can only appear on the left hand side of += or -= (except when used from within the type 'Game1')

How can I call OnLoadingContent from Options.cs?

In my Android project:

Activity1.cs:

protected override void OnCreate(Bundle bundle)
{   
    base.OnCreate(bundle);   
    SetContentView(Resource.Layout.activity_main);   
    CrossMediaManager.Current.Init(this);    
    _game = new Game1();   
    _game.OnLoadingContent += G_OnLoadingContent;
    _view = _game.Services.GetService(typeof(View)) as View;
    SetContentView(_view);
    _game.Run();
}

private void G_OnLoadingContent(object sender, System.EventArgs e)
{  
    customDialog = new VideoDialog(this);  
    customDialog.SetCancelable(false);
    customDialog.Show();
    CrossMediaManager.Current.MediaItemFinished += (s, e) =>   
    {
        customDialog.Cancel();
    };
}

In my SharedCode project:

Game1.cs:

public event EventHandler OnLoadingContent;
public event EventHandler OnLoadingContentRemove;
Options MyOptions;
MyOptions = new Options(this, GraphicsDevice);
MyOptions.Load(Content);

Options.cs:

using System;
using MediaManager;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Content;

namespace SharedCode
{
public class Options
{
private Game1 game1;
GraphicsDevice graphicsDevice;

public Options(Game1 game, GraphicsDevice device)
{
    game1 = game;
    graphicsDevice = device;
}

public async void Load(ContentManager content)
{
    game1.OnLoadingContent?.Invoke(this, new EventArgs());
    await CrossMediaManager.Current.Play("https://videos.pexels.com/video-files/7356431/7356431-hd_1280_720_25fps.mp4");
}
}
}

Accepted Answer

Hello,

Event handlers only can be added or removed within the Game1 class where the event is declared.

public class Game1
{
    public event EventHandler OnLoadingContent;

    public void SomeMethod()
    {
        // Subscribe to the event
        this.OnLoadingContent += YourEventHandlerMethod;

        // Unsubscribe from the event
        this.OnLoadingContent -= YourEventHandlerMethod;
    }

    private void YourEventHandlerMethod(object sender, EventArgs e)
    {
        // Event handling logic
    }
}

Based on your previous link, do you want to popup dialog and play the video by Game1 class in the Options.cs?

If so, you can add an attribute in the Game1's constructor. Then create a method(called ShowTheVideo for testing) to popup a dialog and play the video. By the way, please remove the await CrossMediaManager.Current.Play("https://archive.org/download/BigBuckBunny_328/BigBuckBunny_512kb.mp4"); in the LoadContent method, and add ShowTheVideo(); directly.

public class Game1 : Game
  {
      private GraphicsDeviceManager _graphics;
      private SpriteBatch _spriteBatch;
      private Activity1 activity1;
      public Game1(Activity1 activity1)
      {
          this.activity1 = activity1;
          _graphics = new GraphicsDeviceManager(this);
          Content.RootDirectory = "Content";
          IsMouseVisible = true;
      }

    public async void ShowTheVideo()
    {
 
     VideoDialog customDialog = new VideoDialog(activity1);
     customDialog.SetCancelable(false);
     customDialog.Show();
     await CrossMediaManager.Current.Play("https://sec.ch9.ms/ch9/5d93/a1eab4bf-3288-4faf-81c4-294402a85d93/XamarinShow_mid.mp4");
     CrossMediaManager.Current.MediaItemFinished += (s, e) =>
     {
         customDialog.Cancel();
     };
    }

     protected override async void LoadContent()
        {
            _spriteBatch = new SpriteBatch(GraphicsDevice);
         //   await CrossMediaManager.Current.Play("https://archive.org/download/BigBuckBunny_328/BigBuckBunny_512kb.mp4");

ShowTheVideo();
        }
}

In the end, you can call game1.ShowTheVideo(); in the Load method of Options class.

public class Options
{
private Game1 game1;
GraphicsDevice graphicsDevice;

public Options(Game1 game, GraphicsDevice device)
{
    game1 = game;
    graphicsDevice = device;
}

public async void Load(ContentManager content)
{
    game1.ShowTheVideo();
   // await CrossMediaManager.Current.Play("https://videos.pexels.com/video-files/7356431/7356431-hd_1280_720_25fps.mp4");
}
}

Best Regards,

Leon Lu

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Error CS0070: The event 'Game1.OnLoadingContent' can only appear on the left hand side of += or -= (except when used from within the type 'Game1')

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