Member Avatar for linq

how can I assign this values then I could deside where and when to create and paint.

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  • Latest Post Latest Post by Ancient Dragon

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Short answer: those messages come from Windows. asked how to “assign” them to control when creation and painting happen; correctly pointed to the API that drives that behavior. The important part is how Windows generates and delivers those messages, not treating the numeric constants as something to fabricate.

WM_CREATE is sent by the system as part of the window creation sequence (it is delivered synchronously during CreateWindow/CreateWindowEx). WM_PAINT is a posted message that the system enqueues when a window’s update region is non‑empty; handling it normally requires the BeginPaint/EndPaint pair. See the official docs for details on WM_CREATE and WM_PAINT and on how the Windows message queue works: WM_CREATE, WM_PAINT, about messages and message queues.

Practical implications:

  • Initialization and resource allocation belong in the creation path (WM_CREATE or earlier), and cleanup in WM_DESTROY.
  • Painting code belongs in WM_PAINT and must validate the update region (BeginPaint/EndPaint). For an immediate redraw, mark the region with InvalidateRect and call UpdateWindow rather than posting WM_PAINT manually.
  • For thread-to-window notifications, post a custom message (WM_USER+n) to the window thread instead of faking system messages.

Troubleshooting notes:

  • If WM_PAINT never arrives, check the thread’s message loop and whether BeginPaint is used correctly (unvalidated regions will keep WM_PAINT posted).
  • If WM_CREATE handler returns -1 the CreateWindow call fails; inspect the CREATESTRUCT and return values.

Using the documented APIs keeps the system bookkeeping correct and avoids subtle bugs from manually posting system messages.

Member Avatar for Ancient Dragon

InvalidateRect() causes WM_PAINT message. CreateWindow() causes WM_CREATE message. You should not post either of those messages yourself but call the win32 api functions.

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