具有ImageList的图像的面向对象设计

Question

I am making a class which represents and Image, and with Windows, you store images in ImageList controls. This class will be used to handily add images to other controls like ListViews or Buttons, or simply to draw on the screen. My question is: what is the proper design for something like this? Should each Image have it's own ImageList of one image, or should the Image class have one giant ImageList for all the instances of it, or what? I don't know much about the internals of the Windows classes so I don't know how "heavy" the ImageList class is, but if it's relatively inexpensive, I was leaning toward the "each instance has it's own imagelist." What do you recommend?

Answer 1

Generally, I would recommend something in between.

It seems silly to have a different image list for each image. They're designed to store collections of images and make managing these collections more efficient, not so much to hold a single image.

Then again, there are drawbacks to trying to use one giant image list for all of your images. Namely, all of the images in an image list must be of the same size. If this isn't true of your images, you'll need to place them in separate image lists.

But more to the point, I'm not really sure why you're considering creating an image class that contains an image list in the first place. Unless you're going to be storing icons/cursors or need to worry about masks, why not just encapsulate a handle to the bitmap representing the image? That's the same thing you're going to be passing into the image list's "Add" method anyway.