Windows , . : PerForm() ( API Windows), API Win32 SendMessage() PostMessage().
PerForm(), TControl:
function TControl.Perform(Msg: Cardinal; WParam, LParam: Longint): Longint;
, :
RetVal:= ControlName.PerForm(MessageID, wParam, lParam);
PerForm() , . , API Windows.
API SendMessage() PostMessage(), Windows :
function SendMessage(hWnd: HWND; Msg: UINT; wParam: WPARAM;
lParam: LPARAM): LRESULT; stdcall;
function PostMessage(hWnd: HWND; Msg: UINT;
wParam: WPARAM; lParam: LPARAM): BOOL; stdcall;
hWnd ; Msg ; wParam lParam .
SendMessage() PerForm() , PostMessage() , .
SendMessage() , . PostMessage() , , .
, , . , , Windows WM_USER $7FFF.
:
const
TestMsg = WM_USER + 100; //
type
TForm1 = class(TForm)
private
// :
procedure MyMessage(var Msg: TMessage); message TestMsg;
end;
...
procedure TForm1.MyMessage(var Msg: TMessage);
begin
ShowMessage(' TestMsg');
Msg.Result:= 1; //
end;
:
if Form1.PerForm(TestMsg, 0, 0) = 1 then
ShowMessage(' ');
if SendMessage(Form1.Handle, TestMsg, 0, 0) = 1 then
ShowMessage(' ');
if PostMessage(Form1.Handle, TestMsg, 0, 0) then
ShowMessage(' ');
Delphi
, . Delphi, , . , . .
-.
"On", .
Delphi Windows, . VCL Windows WM_XXX:
