delphi - SendInput 显示不按顺序发送的数据

Question

我正在通过将字符串发送到备忘录来尝试 SendInput。我将 SendInput 命令与对 Memo.Lines.Add('....') 的调用混合在一起。令我惊讶的是，所有 Memo.Lines.Add 命令都在任何 SendInput 例程之前执行。为什么？如何让备忘录以正确的顺序显示信息？

我的代码如下所示:

procedure TForm1.Button1Click(Sender: TObject);
const
  AStr = '123 !@# 890 *() abc ABC';
var
  i: integer;
  KeyInputs: array of TInput;

  procedure KeybdInput(VKey: Byte; Flags: DWORD);
  begin
    SetLength(KeyInputs, Length(KeyInputs)+1);
    KeyInputs[high(KeyInputs)].Itype := INPUT_KEYBOARD;
    with  KeyInputs[high(KeyInputs)].ki do
    begin
      wVk := VKey;
      wScan := MapVirtualKey(wVk, 0);
      dwFlags := Flags;
    end;
  end;

begin
  Memo1.SetFocus;
  Memo1.Lines.Add('AStr := ' + AStr);

  Memo1.Lines.Add('');
  Memo1.Lines.Add('Use:   KeybdInput(ord(AStr[i]),0)');
  SetLength(KeyInputs,0);
  for i := 1 to Length(AStr) do KeybdInput(ord(AStr[i]),0);
  SendInput(Length(KeyInputs), KeyInputs[0], SizeOf(KeyInputs[0]));

  Memo1.Lines.Add('');
  Memo1.Lines.Add('Use:   KeybdInput(vkKeyScan(AStr[i]),0)');
  SetLength(KeyInputs,0);
  for i := 1 to Length(AStr) do KeybdInput(vkKeyScan(AStr[i]),0);
  SendInput(Length(KeyInputs), KeyInputs[0], SizeOf(KeyInputs[0]));
end;

我期望结果如下:

但实际上看起来是这样的:

Answer 1

使用 SendInput 发送的键盘输入将通过 Windows 消息传递系统并最终进入应用程序消息队列。在退出 Button1Click() 之前，不会处理消息队列。

When something gets added to a queue, it takes time for it to come out the front of the queue

要按您期望的顺序查看事件，您需要在每个 SendInput() 之后插入对 Application.Processmessages() 的调用。不过，通常不建议调用 Application.ProcessMessages():

The Dark Side of Application.ProcessMessages in Delphi Applications