How to provide animation in a menu item drawn by the owner?

Question

My application is in C # 3.5, Winforms, but this will most likely require P / Invoke, so this is not so strictly related to .NET.

I created user-created menu items through the ContextMenuand classes MenuItem. Everything works well, but for some elements I would like to create a little animation (showing that there is a process associated with the element). Unfortunately, the above two classes do not provide a method Invalidate()or something like that.

My best idea so far is to P / Invoke WindowFromDC()in the first OnDraw, save the resulting descriptor, and then periodically call InvalidateRect()on the descriptor until the menu is closed.

These seem to be hacks, although I haven't tried it yet and am wondering if there is a more elegant way.

Answer 1

Instead of using WindowFromDC, I could suggest calling a GetMenuItemRectfunction to get a bounding box for a specific menu item. Then you can pass the rectangle structure filled with this function into the InvalidateRectfunction .

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