Thread: EM_GETLINE And Unicode?

You need to use SendMessageTimeout and not SendMessage if you want to obtain line counts etc from a multi-line edit/richedit that belongs to another application. Also, but not related to your original problem, if you're going to use SetTimer then make sure you kill it off with KillTimer.

UNICODE is not the problem, the window handle you're using probably is. Try using an explicit handle for a known, open and active richedit/edit control (use spy++ or, if you don't have it, get a free variation from here; use the tool to get the handle of an active edit/richedit control). When you compare that with whatever handle you're trapping in code you'll probably find they're different.

Other test code you might consider implementing include

• Testing the handle you are attempting to use to ensure it actually belongs to an edit/richedit control ( use GetWindowLong/GetWindowLongPtr to test the style bits for ES_MULTILINE (if this style is absent from the window under scrutiny then messages such as EM_GETLINE and EM_GETLINECOUNT will always fail); popup a messagebox if the ES_MULTILINE style is absent).
• Testing the return value from SendMessageTimeOut

If, after taking some or all of these steps, you still have problems then post/attach your amended code.