Adding a Dropper tool

What exactly would I have to do, to create an eye dropper tool in my windows forms application?

Im going to start to hack maplestory and I want the eye dropper tool to select the color of the monster and then click it. Basically the same thing that Runescape trainers do to mine ores...

What I personally do is make a function to check for a hotkey and if the hotkey is pressed you should use a COLORREF variable to store the return value of GetPixel. For coordinate parameters of GetPixel you should call GetCursorPos and store the coordinates in a POINT structure that is global preferably so that you can use it in other functions. Once you call GetPixel you should you store the r g b values in a COLORREF or int. Then you do what you want with it. This is what I do.
Good luck and keep us posted on your progress.

Install a keyboard hook using SetWindowsHookEx so you can trap the next mouseclick to prevent it from happening