Location of the pointer

Hi! I want to make something like the intelisence in the visual studio... When you press "ctrl + space" list box apears with some Items in it... I have done that but now I want toa ask how can I take the location of the Pinter so I can set the location of that listBox. For now my list box has fixed location, the midle of the textBox, in witch I am writing... (location of the pointer, not of the mouse) the control that I am writing in, coud be text box or rich text box Thanks