网上有很多的关于模拟按键的例子，经过实验，我选如下一组函数

procedure SendShift(H: HWnd; Down: Boolean);
var
   vKey, ScanCode: Word;
   lParam: longint;
begin
    vKey:= $10;
    ScanCode:= MapVirtualKey(vKey, 0);
    lParam:= longint(ScanCode) shl 16 or 1;
    if not(Down) then
       lParam:= lParam or $C0000000;
    SendMessage(H,WM_KEYDOWN, vKey, lParam);
end;

procedure SendCtrl(H: HWnd; Down: Boolean);
var
   vKey, ScanCode: Word; //wParam
   lParam: longint;
begin
    vKey:= $11;
    ScanCode:= MapVirtualKey(vKey, 0);{虚拟键转换为扫描码}
    lParam:= longint(ScanCode) shl 16 or 1;
    if not(Down) then
       lParam:= lParam or $C0000000;
    SendMessage(H,WM_KEYDOWN, vKey, lParam);
end;

procedure SendKey(H: Hwnd; Key: char);
var
  vKey, ScanCode, wParam: Word;
  lParam, ConvKey: longint;
  Shift, Ctrl: boolean;
begin
    ConvKey:= OemKeyScan(ord(Key));
    Shift:= (ConvKey and $00020000) <> 0;
    Ctrl:= (ConvKey and $00040000) <> 0;
    ScanCode:= ConvKey and $000000FF or $FF00;
    vKey:= ord(Key);
    wParam:= vKey;
    lParam:= longint(ScanCode) shl 16 or 1;
    if Shift then SendShift(H, true);
    if Ctrl then SendCtrl(H, true);
    SendMessage(H, WM_KEYDOWN, vKey, lParam);
    SendMessage(H, WM_CHAR, vKey, lParam);
    lParam:= lParam or $C0000000;
    SendMessage(H, WM_KEYUP, vKey, lParam);
    if Shift then SendShift(H, false);
    if Ctrl then SendCtrl(H, false);
end;

//--模拟键盘输入
procedure SendText(h:THandle; str:string);
var
  n:integer;
begin
  n:=1;
  while n<>length(str)+1 do
  begin
    if ord(str[n])<130 then
      begin
        SendMessage(h, $0286,ord(str[n]),0);
        n:=n+1;
      end
    else
      begin
        SendMessage(h, $0286,(ord(Str[n]) shl 8)+ord(Str[n+1]),0);
        n:=n+2;
      end;
  end;
end;