C# - Are there (similar) .AddChild and .AddEventListeners in C# and can they be used on Graphics?

Question

Hello,

I'm new to C# but not to OOP.

I'd like to make a "canvas" panel on which a user can draw shapes by mouseClick-ing but also delete them (nothing fancy, fixed sizes and whatnot, plain old pen objects). Like I said, I want the user to be able to delete whatever objects he alt-clicks on.

I'm not sure how exactly could I go about doing this. If I were using Flash, I'd probably do something like:

my_circle_object = new disc-or-whatever-etc;
canvas.addChild(my_circle_object);
my_circle_object.AddEventListener(MouseClickEvent, function_to_remove_child);

Now, since compiled languages are the devil when it comes to simple front-end UI related stuff, I'm sure It'll take 20 times more code to write this in C#. But, is there anything similar to my example?

I've spent all afternoon reading on things like GraphicsContainers, SmoothingPaint, Graphics Persistence using bitmaps etc. but I never found a simple add event method..

Thank you

Answer 1

The objects that you draw using the shape methods on a Graphics object (e.g. DrawLine, DrawEllipse, DrawRect, etc.) do not represent conceptual objects as far as the graphics API is concerned. Calling those functions simply draws the item to the graphics surface as a bitmap. Once that's done, there's nothing there to attach an event to.

You'll need to create your own shape types and have them draw themselves to the graphics object. You'll have to attach to the appropriate mouse events on whatever control you're using (I'm assuming a Panel) and do your own collision detection.