How to communicate with other software from my onscreen keyboard?

Question

I need to make a C# or Java application somewhat like "windows onscreen keyboard". I am not sure how to fill the alphabets into other applications on clicking buttons on my form. How do I communicate with the focused textbox or textarea on any given windows software, browser etc.? Any hints or code examples please?

Answer 1

There is an informative video on youtube about this very subject:

http://www.youtube.com/watch?v=VgFXwWQwE9k

And this is the source: http://pastebin.com/drWY3qnz