SendInput 与 keybd_event

MSDN 指出 keybd_event 已被 SendInput 取代。在重写过程中，我改用 SendInput...这很好except当尝试发送 Alt 键组合时。在 Win7 64 位系统上（尚未在其他地方尝试过），发送 Alt 键会导致击键在目标应用程序中出现之前出现很长的延迟。

有什么想法吗？还是我做错了什么？现在，我回到了 keybd_event——下面的第二个版本。

//Keyboard input from this version appears only after a ~4-5 second
//time lag...
procedure SendAltM;
var
  KeyInputs: array of TInput;
  KeyInputCount: Integer;
  //--------------------------------------------
  procedure KeybdInput(VKey: Byte; Flags: DWORD);
  begin
    Inc(KeyInputCount);
    SetLength(KeyInputs, KeyInputCount);
    KeyInputs[KeyInputCount - 1].Itype := INPUT_KEYBOARD;
    with  KeyInputs[KeyInputCount - 1].ki do
    begin
      wVk := VKey;
      wScan := MapVirtualKey(wVk, 0);
      dwFlags := KEYEVENTF_EXTENDEDKEY;
      dwFlags := Flags or dwFlags;
      time := 0;
      dwExtraInfo := 0;
    end;
  end;
begin
  KeybdInput(VK_MENU, 0);                 // Alt
  KeybdInput(Ord('M'), 0);                 
  KeybdInput(Ord('M'), KEYEVENTF_KEYUP);   
  KeybdInput(VK_MENU, KEYEVENTF_KEYUP);   // Alt
  SendInput(KeyInputCount, KeyInputs[0], SizeOf(KeyInputs[0]));
end;


//Keyboard input from this version appears immediately...
procedure SendAltM;
begin
  keybd_event( VK_MENU, MapVirtualkey( VK_MENU, 0 ), 0, 0);
  keybd_event( Ord('M'), MapVirtualKey( Ord('M'),0), 0, 0);
  keybd_event( Ord('M'), MapVirtualKey( Ord('M'),0), KEYEVENTF_KEYUP, 0);
  keybd_event( VK_MENU, MapVirtualkey( VK_MENU, 0 ), KEYEVENTF_KEYUP, 0);
end;

问题1

你没有初始化KeyInputCount。所以它的值是未定义的。调用前将其设置为零KeybdInput第一次。或者只是摆脱它并使用Length(KeyInputs)反而。

问题2

您的设置dwFlags是不正确的。不包括KEYEVENTF_EXTENDEDKEY。您没有将其包含在调用的代码中keybd_event，并且您不应该将其包含在内SendInput.

更正代码

这个版本有效。

procedure SendAltM;
var
  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
  KeybdInput(VK_MENU, 0);                 // Alt
  KeybdInput(Ord('M'), 0);
  KeybdInput(Ord('M'), KEYEVENTF_KEYUP);
  KeybdInput(VK_MENU, KEYEVENTF_KEYUP);   // Alt
  SendInput(Length(KeyInputs), KeyInputs[0], SizeOf(KeyInputs[0]));
end;