模拟的 Shift+Right 键并不总是在 Windows 上有效

Question

我有以下用Delphi 10.1 Berlin编写的代码，它试图在Windows上模拟Shift+向右箭头键，以便在备忘录中选择文本。这是一个Delphi Firemonkey项目，但这对我的问题来说无关紧要。问题是这段代码在某些 Windows 机器上执行它应该做的事情(逐个字母选择文本(，但在其他机器上失败(只移动光标 pos，就好像 shift 键被忽略一样(。代码的失败似乎不是特定于Windows版本，因为它适用于win 8.1以及某些Win 10 Fall Creatores Updates，但在某些Win 10 Fall Creators安装上失败。它似乎也不是特定于SendInput的mehtod，因为使用keybd_event会出现相同的现象。有人有什么想法吗？

 unit Unit63;
interface
uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.StdCtrls,
  FMX.Controls.Presentation, FMX.ScrollBox, FMX.Memo;
type
  TForm63 = class(TForm)
    mmo1: TMemo;
    btn1: TButton;
    procedure btn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form63: TForm63;
implementation
uses windows;
{$R *.fmx}
procedure SendShiftRight;
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 := Flags;
      time := 0;
      dwExtraInfo := 0;
    end;
  end;
begin
  KeyInputCount := 0;
  KeybdInput(VK_SHIFT, 0);                // Shift
  KeybdInput(VK_RIGHT, 0);                 // Right
  KeybdInput(VK_RIGHT, KEYEVENTF_KEYUP);   // Right
  KeybdInput(VK_SHIFT, KEYEVENTF_KEYUP); // Shift
  SendInput(KeyInputCount, KeyInputs[0], SizeOf(KeyInputs[0]));
end;
procedure PostKeyEx32(key: Word; const shift: TShiftState; specialkey: Boolean);
{************************************************************
* Procedure PostKeyEx32
*
* Parameters:
*  key    : virtual keycode of the key to send. For printable
*           keys this is simply the ANSI code (Ord(character)).
*  shift  : state of the modifier keys. This is a set, so you
*           can set several of these keys (shift, control, alt,
*           mouse buttons) in tandem. The TShiftState type is
*           declared in the Classes Unit.
*  specialkey: normally this should be False. Set it to True to
*           specify a key on the numeric keypad, for example.
* Description:
*  Uses keybd_event to manufacture a series of key events matching
*  the passed parameters. The events go to the control with focus.
*  Note that for characters key is always the upper-case version of
*  the character. Sending without any modifier keys will result in
*  a lower-case character, sending it with [ssShift] will result
*  in an upper-case character!
// Code by P. Below
************************************************************}
type
  TShiftKeyInfo = record
    shift: Byte;
    vkey: Byte;
  end;
  byteset = set of 0..7;
const
  shiftkeys: array [1..3] of TShiftKeyInfo =
    ((shift: Ord(ssCtrl); vkey: VK_CONTROL),
    (shift: Ord(ssShift); vkey: VK_SHIFT),
    (shift: Ord(ssAlt); vkey: VK_MENU));
var
  flag: DWORD;
  bShift: ByteSet absolute shift;
  i: Integer;
begin
  for i := 1 to 3 do
  begin
    if shiftkeys[i].shift in bShift then
      keybd_event(shiftkeys[i].vkey, MapVirtualKey(shiftkeys[i].vkey, 0), 0, 0);
  end; { For }
  if specialkey then
    flag := KEYEVENTF_EXTENDEDKEY
  else
    flag := 0;
  keybd_event(key, MapvirtualKey(key, 0), flag, 0);
  flag := flag or KEYEVENTF_KEYUP;
  keybd_event(key, MapvirtualKey(key, 0), flag, 0);
  for i := 3 downto 1 do
  begin
    if shiftkeys[i].shift in bShift then
      keybd_event(shiftkeys[i].vkey, MapVirtualKey(shiftkeys[i].vkey, 0),
        KEYEVENTF_KEYUP, 0);
  end; { For }
end; { PostKeyEx32 }

procedure TForm63.btn1Click(Sender: TObject);
begin
  mmo1.SetFocus;
  SendShiftRight;
  // PostKeyEx32(vkRight, [ssShift], False);    // doesn't work either
end;

end.

Answer 1

事实证明，SendInput 仍然需要扩展密钥的KEYEVENTF_EXTENDEDKEY。然而，不能依赖MapVirtualKey来返回从Vista开始的扩展键值(224(。

修改代码以使用 ExtendedKeyFlag：

begin
  KeyInputCount := 0;
  KeybdInput(VK_SHIFT, ExtendedKeyFlag(VK_SHIFT));                   // Shift
  KeybdInput(VK_RIGHT, ExtendedKeyFlag(VK_RIGHT));                   // Right
  KeybdInput(VK_RIGHT, ExtendedKeyFlag(VK_RIGHT) or KEYEVENTF_KEYUP);// Right
  KeybdInput(VK_SHIFT, ExtendedKeyFlag(VK_SHIFT) or KEYEVENTF_KEYUP);// Shift
  SendInput(KeyInputCount, KeyInputs[0], SizeOf(KeyInputs[0]));
end;

ExtendedKeyFlag 绕过 MapVirtualKey 并映射扩展密钥：

/// <summary>
///   Returns KEYEVENTF_EXTENDEDKEY if part of ExtendedKeys
/// </summary>
/// <remarks>
///   No API exists to properly return the Extended Keys in Vista+
///   <note type="warning">
///     Do NOT trust in MapVirtualKeyEx(MAPVK_VK_TO_VSC_EX) (&gt;= Vista) because it does not return the extended flag for some keys although they are extended keys
///   </note>
/// </remarks>
/// <seealso href="http://letcoderock.blogspot.ca/2011/10/sendinput-with-shift-key-not-work.html">
///   SendInput with SHIFT key does not work!?
/// </seealso>
/// <seealso href="https://stackoverflow.com/questions/21197257/keybd-event-keyeventf-extendedkey-explanation-required#21202784">
///   keybd_event KEYEVENTF_EXTENDEDKEY explanation required
/// </seealso>
function ExtendedKeyFlag(const VKey : Word): Cardinal;
begin
  If (VKey in [VK_UP, VK_DOWN, VK_LEFT, VK_RIGHT, VK_HOME, VK_END, VK_PRIOR, VK_NEXT, VK_INSERT, VK_DELETE]) then Result := KEYEVENTF_EXTENDEDKEY
  else Result := 0;
end;