Can C# Interact With Other Programs?

Question

I'm considering learning C# in order to develop some custom business solutions, and I just wanted to ask some experts first to get an idea of the language's capabilities. Specifically, there is a third-party program that I use manually for work, basically clicking items within the program in order to generate a report.

Is it possible to create a C# application that could interact with this 3rd party program and automate all of the manual clicking I have to do? To be clear, I would not be able to modify the 3rd party program in any way. Also, this would be for Windows, and the 3rd party program is NOT Microsoft software.

Is this possible, and if so where would it rank from 1-10 in terms of difficulty.

Thanks!

Vulpes · Answer

Yes it's possible. If the 3rd party application has keyboard shortcuts for clicking the items in question then it's relatively easy to do as you can simply send keystrokes to the application using .NET's SendKeys.Send method. However as there can sometimes be timing issues with this type of application I'd put the difficulty at 5 out of 10. If the 3rd party application doesn't have keyboard shortcuts then you have to resort to making calls to the underlying Win32 API to click the items. Whilst this is perfectly possible from C# using a technique known as 'platform invoke' it's not particularly easy to get right (particularly if you have to drill down through several layers of 'window' to get at the item) and I'd therefore put the difficulty at 7 out of 10. There's a low-level utility called Spy++ which is invaluable for this sort of work. Hope these remarks are of some help to you.

Vulpes · Answer

If you need to select an item on a menu listbox or combobox then Spy++ will tell you what the window handle of the control in question is. You can then use the Win32 API function SendMessage to send the control the appropriate message to select the item you want. There are different sets of messages for each control type. If you don't know in advance what the list items are called then there are messages which enable you read the contents before you select one. Sometimes you'll find that the control is buried in a hierarchy of windows and Spy++ will enable you to navigate these windows and dig down to the control you want.

Stefon · Answer

Thanks for the overview! It would definitely have to be the second method since there aren't shortcuts for this. Basically the application has a list of items in it in one of those scroll bar menus and I have to manually click those items based on a reference document of my own. E.g. A B C D E ...etc. Would that Spy++ tool (or something similar) allow me to see what the list items are called so that I can reference them in the coding?