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lcl: prevent creating more than one DC in TControlCanvas.CreateHandle

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git-svn-id: trunk@29648 -
This commit is contained in:
paul 2011-02-22 08:07:13 +00:00
parent 5eaebdc1e4
commit 53c17af765
1 changed files with 13 additions and 0 deletions
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13
lcl/include/controlcanvas.inc
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@ -77,6 +77,8 @@ end;
Creates the handle ( = object).
------------------------------------------------------------------------------}
procedure TControlCanvas.CreateHandle;
var
WinControl: TWinControl;
begin
//DebugLn('[TControlCanvas.CreateHandle] ',FControl<>nil,' DC=',DbgS(FDeviceContext,8),' WinHandle=',DbgS(FWindowHandle,8));
if FControl = nil then
@ -85,6 +87,17 @@ begin
begin
if ControlIsPainting then
debugln(['TControlCanvas.CreateHandle WARNING: accessing the canvas of '+DbgSName(FControl)+' is not supported outside of paint message']);
if (FDeviceContext = 0) then
begin
// access to window handle can cause another TControlCanvas.CreateHandle
// as result we get a resource leak. To prevent this require handle before
// accessing it
if FControl is TWinControl then
WinControl := TWinControl(FControl)
else
WinControl := FControl.Parent;
WinControl.HandleNeeded;
end;
if FDeviceContext = 0 then
begin
// store the handle locally since we need it to check (and do not