To find the existing instance of Internet Explorer, we need to use the FindWindowEx and EnumChildWindows Windows API calls.
FindWindowEx will find a window with a given classname – we then use the EnumChildWindows routine to search that application for the EditControl (read: address text box) in Internet explorer. Once the textbox has been found, a simple SendMessage call can be made with the WM_SETTEXT parameter to set the address.
Once the text has been set in IE’s address textbox, we can simply do another SendMessage call, this time with WM_KEYDOWN and passing the ‘return’ key constant.
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