TControlCanvas.FreeHandle procedure

Declaration

procedure FreeHandle; override

Description

FreeHandle is an overridden method in TControlCanvas. It calls the inherited method on entry to set the value in Handle to 0 (the unassigned value). If a device context (DC) has been allocated for the window handle (HWND), the ReleaseDC routine is called to release the device context.

FreeHandle MUST be called when the Handle for a control which uses a canvas instance is destroyed/released. For windowed controls this generally occurs in the DestroyWnd method. For non-windowed controls this occurs when the parent window handle is freed.

See also

• Destroy
• Control
• TCanvas.Handle
• TCanvas.FreeHandle
• ReleaseDC
• TWinControl.WindowHandle
• TWinControl.DestroyWnd
• TWinControl.DestroyHandle