Redirect cmd output to string in c++ or in memobox?

Question

I have two objects in my form application. First is a listbox where i want to hold the cmd output, and the second is button who have command like, WinExec("cmd /c ipconfig -all", 0);, so question is how to redirect cmd output to the list box. For example, I'd prefer not to save output of ipconfig in file & load from file text to list box.