SendMessage makes use of the API, and is not a "pure" visual basic function. So newbies like me have no clue, as how to implement it.

I want to send the string "Merge.txt" to another non-visual basic application. The text window it is going to, is called 1013.
I've used VB.NET to find the name 1013, by simply opening the non-vb app.

Please post a clear full code or explanation of how to send a message to another app's textbox.