Selecting an item in a list box in an external program

Hello,

I am currently working on writing a program for work, and I have come across something that I dont know exactly how to do.

The program that I am working with runs while another program is running. The program I am writing is to "use" (act as a person using the program itself) the other program.

The program that this program is interfacing with and using has a big list box with a few thousand entries in it. This list box allows multiple items in it to be selected at once.

The problem at the moment is that a actual human has to look at an excel list, and then find these entries in this big list box, hold down the control button and click all of the items in the list that are on the excel sheet. What I am hoping to do is create a program that will read the excel sheet, get the contents of this list box, and then select the items in the list box that are also on the excel sheet.

I know how to do all the code so far except for the part of selecting the items in the actual list box.


Since the program that I need to select the item in the list box in is an external program (its not the program that I am coding, its the one I am coding this program to modify) I assume that in order to select the item I will have to use some sort of API code.

Any person that can help me out with this (tell me the API that I could use, give me a code example, whatever) to select an item in a list box in an external program, would be VERY appreciated.

Thanks a million,

John