My application is associated with a file type, when the user clicks on a file of this type my application starts and opens that file, if the user redo that, the application will start again resulting two instances of the application. That I want is an example or were I can find info on making my application communicating with explorer using DDE preventing that situation.
Also I want if the user clicks to another file, my program to be able to get the name of the file and open it in the same instance of my program. E.g. MS Word, if you click to open a word file from explorer and word is already running,
word will not run again, but will open the file in the same word instance.