在光标位置打开表格，Delphi

Question

I am trying to figure out how to position a Form to open at a given mouse location, despite my monitor settings.

In the Form's OnCreate event, I have this:

procedure TSplashScreen.FormCreate(Sender: TObject);
Var
   oMousePos: TPoint;
   nLeft, nTop: Integer;
begin
    Scaled := false;
    PixelsPerInch := Screen.PixelsPerInch;
    Scaled := true;
    //Position:=poScreenCenter;

   //center form for 2nd monitor   //zzz
   if (Screen.MonitorCount > 1) then                             //zzz
   begin
      GetCursorPos(oMousePos);
      if (oMousePos.X > Screen.Width) or (oMousePos.X < 0) then
      begin
         Self.Position := poDesigned;
         nLeft := Screen.Monitors[1].Left + Round(Screen.Monitors[1].Width / 2) - Round(Self.Width / 2);
         nTop := Screen.Monitors[1].Top + Round(Screen.Monitors[1].Height / 2) - Round(Self.Height / 2);
         Self.Left := nLeft;
         Self.Top := nTop;
      end;
   end;
end;

When I have 2 monitors, and monitor 1 is set as primary monitor, the Form will open at the mouse cursor.

However, if I set monitor 2 to primary, the Form will always open on monitor 2.

Answer 1

If you just want to position the Form on the same monitor that the mouse cursor is currently in, use the Win32 API MonitorFromPoint() function (which is wrapped by the VCL's TScreen.MonitorFromPoint() method), eg:

procedure TSplashScreen.FormCreate(Sender: TObject);
var
  r: TRect;
begin
  if (Screen.MonitorCount > 1) then
  begin
    r := Screen.MonitorFromPoint(Mouse.CursorPos).WorkareaRect;
    Self.Position := poDesigned;
    Self.Left := r.Left + ((r.Width - Width) div 2);
    Self.Top := r.Top + ((r.Height - Height) div 2);
    { alternatively:
    Self.SetBounds(
      r.Left + ((r.Width - Width) div 2),
      r.Top + ((r.Height - Height) div 2),
      Width, Height);
    }
  end else begin
    Self.Position := poScreenCenter;
  end;
end;