解决方法
几年前,我对表单遇到了同样的问题：我正在寻找一种方法来确定表单是否实际可见(甚至只是部分)给用户.
特别是当它应该是可见的并且显示为True但是窗口实际上完全落后于另一个窗口.
这是代码,它可以适用于WinControl ……
特别是当它应该是可见的并且显示为True但是窗口实际上完全落后于另一个窗口.
这是代码,它可以适用于WinControl ……
{----------------------------------------------------------}
function IsMyFormCovered(const MyForm: TForm): Boolean;
var
MyRect: TRect;
MyRgn,TempRgn: HRGN;
RType: Integer;
hw: HWND;
begin
MyRect := MyForm.BoundsRect; // screen coordinates
MyRgn := CreateRectRgnIndirect(MyRect); // MyForm not overlapped region
hw := GetTopWindow(0); // currently examined topwindow
RType := SIMPLEREGION; // MyRgn type
// From topmost window downto MyForm,build the not overlapped portion of MyForm
while (hw<>0) and (hw <> MyForm.handle) and (RType <> NULLREGION) do
begin
// nothing to do if hidden window
if IsWindowVisible(hw) then
begin
GetWindowRect(hw,MyRect);
TempRgn := CreateRectRgnIndirect(MyRect);// currently examined window region
RType := CombineRgn(MyRgn,MyRgn,TempRgn,RGN_DIFF); // diff intersect
DeleteObject( TempRgn );
end; {if}
if RType <> NULLREGION then // there's a remaining portion
hw := GetNextWindow(hw,GW_HWNDNEXT);
end; {while}
DeleteObject(MyRgn);
Result := RType = NULLREGION;
end;
function IsMyFormVisible(const MyForm : TForm): Boolean;
begin
Result:= MyForm.visible and
isWindowVisible(MyForm.Handle) and
not IsMyFormCovered(MyForm);
end;