C ++ DrawText和TextOut什么也不显示

Question

Where do I use TextOut or DrawText?

TCHAR text[]= "My First Window";
     RECT rc;
     HDC wdc = GetWindowDC(hWnd);
     GetClientRect (hWnd, &rc);
     SetTextColor(wdc, 0x00000000);
     SetBkMode(wdc,TRANSPARENT);
     rc.left=40;
     rc.top=10;
     TextOut(hdc,rc.left,rc.top,text,ARRAYSIZE(text));
     EndPath(hdc);
     SelectClipPath(hdc, RGN_AND);

I'm placing this in WM_CREATE:

The result is a blank window. I can provide more code if need be, but it's just a standard Win32 blank window.

This is my first real Win32 application and I've googled and searched for an hour without finding the answer to my question.

Thank you

Answer 1

Windows doesn't work like that. You can't just paint once and expect what you painted to be displayed forever. Your window probably isn't even visible when WM_CREATE is handled.

(as an aside, you are also leaking wdc in the above code, and interchanging wdc with hdc ).

You need to handle the WM_PAINT message and do your painting in there. Call BeginPaint() to get an HDC that you can draw on, and call EndPaint() when finished.

You should get a beginner's book in Win32 programming as handling WM_PAINT is pretty basic stuff. Start with the MSDN documentation:

Painting and Drawing