InputBoxNumeric

//InputBoxNumeric (with MaxLength and numbers only)
//Coded by HEX0x29A
function InputBoxNumeric(Caption: string; Prompt: string; Default: Integer;
  const MaxLength: Integer = 0): Integer;
type
  PThreadParam = ^TThreadParam;

  TThreadParam = packed record
    dwLength: DWORD;
    dwParent: DWORD;
    szCaption: string;
  end;
var
  Param: TThreadParam;
  hThread: DWORD;

  procedure InputBoxThreadProc(Param: Pointer); stdcall;
  var
    wnd, tmp: HWND;
  begin
    wnd := 0;
    repeat
      Application.ProcessMessages;
      tmp := FindWindowW('TInputQueryForm', PWideChar(WideString(PThreadParam(Param).szCaption)));
      if tmp <> 0 then
      begin
        if GetParent(tmp) = PThreadParam(Param).dwParent then
        begin
          wnd := FindWindowEx(tmp, 0, 'TEdit', nil);
          if wnd <> 0 then
          begin
            SendMessage(wnd, EM_LIMITTEXT, PThreadParam(Param).dwLength, 0);
            SetWindowLong(wnd, GWL_STYLE, GetWindowLong(wnd, GWL_STYLE) or ES_NUMBER);
          end;
        end;
      end;
    until wnd <> 0;
    ExitThread(0);
  end;

begin
  with Param do
  begin
    dwParent := Application.ActiveFormHandle;
    dwLength := MaxLength;
    szCaption := Caption;
  end;
  CreateThread(nil, 0, @InputBoxThreadProc, @Param, 0, hThread);
  Result := StrToIntDef(InputBox(Caption, Prompt, IntToStr(Default)), 0);
end;