Windows多桌面切换（CreateDesktop，SwitchDesktop函数）

unit Unit1;  

interface  

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Menus, StdCtrls, Buttons, ExtCtrls,
  TrayIconForm, AppEvnts;  

type
  TShareInfo = record
    Actived : array [ 1..4 ] of boolean;
  end;
  PShareInfo = ^TShareInfo;  

  TForm1 = class(TForm)
    N1: TMenuItem;
    N2: TMenuItem;
    N3: TMenuItem;
    N11: TMenuItem;
    N21: TMenuItem;
    N31: TMenuItem;
    N41: TMenuItem;
    BitBtn2: TBitBtn;
    Panel1: TPanel;
    Image1: TImage;
    Label1: TLabel;
    Label2: TLabel;
    Edit1: TEdit;
    Label3: TLabel;
    Label4: TLabel;
    N4: TMenuItem;
    PopupMenu1: TPopupMenu;
    ApplicationEvents1: TApplicationEvents;
    procedure N3Click(Sender: TObject);
    procedure N2Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
    procedure N4Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure ApplicationEvents1Minimize(Sender: TObject);
    procedure N11Click(Sender: TObject);
    procedure TrayIcon1DblClick(Sender: TObject);
  private
    { Private declarations }
    RunningOnDesktop: integer;
    Failed : boolean;
    procedure OnHotKey(var Msg: TMessage); message WM_HOTKEY;
  public
    { Public declarations }
  end;  

var
  Form1: TForm1;  

implementation  

{$R *.dfm}
{$R UAC.res}  

procedure SwitchToDesktop(number: integer);
var name: string;
  DsktpHandle: HDESK;
  SysPath: array[1..MAX_PATH] of char;
  PPath: PChar;
  StrPath: string;
  len: integer;
  si: STARTUPINFO;
  pi: PROCESS_INFORMATION;
begin
  if number = 1 then
    name := ‘Default‘
  else
    name := ‘NewDesktop‘ + inttostr(number);  

  ZeroMemory(@si, sizeof(STARTUPINFO));
  si.cb := sizeof(STARTUPINFO);
  si.dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
  si.wShowWindow := SW_SHOW;
  si.lpDesktop := PChar(Name);  

  DsktpHandle := OpenDesktop(pchar(Name),
    DF_ALLOWOTHERACCOUNTHOOK, true,
    DESKTOP_CREATEMENU or DESKTOP_CREATEWINDOW or
    DESKTOP_ENUMERATE or DESKTOP_HOOKCONTROL or
    DESKTOP_JOURNALPLAYBACK or
    DESKTOP_JOURNALRECORD or DESKTOP_READOBJECTS or
    DESKTOP_SWITCHDESKTOP or DESKTOP_WRITEOBJECTS);
  if DsktpHandle = 0 then
  begin
    //  桌面不存在，创建桌面
    DsktpHandle := CreateDesktop(PChar(Name), nil, nil,
      DF_ALLOWOTHERACCOUNTHOOK,
      DESKTOP_CREATEMENU or DESKTOP_CREATEWINDOW or
      DESKTOP_ENUMERATE or DESKTOP_HOOKCONTROL or
      DESKTOP_JOURNALPLAYBACK or
      DESKTOP_JOURNALRECORD or DESKTOP_READOBJECTS or
      DESKTOP_SWITCHDESKTOP or DESKTOP_WRITEOBJECTS,
      nil);
    if DsktpHandle = 0 then
    begin
      ShowMessage(‘打开桌面失败! ‘ + SysErrorMessage(GetLastError));
      exit;
    end;  

    PPath := @SysPath;
    len := GetWindowsDirectory(@SysPath, MAX_PATH);
    SetString(StrPath, PPath, len);
    if (not CreateProcess(PChar(StrPath + ‘/explorer.exe‘), nil, nil, nil, True, 0, nil, nil, si, pi)) then
    begin
      ShowMessage(‘进程创建失败! ‘ + SysErrorMessage(GetLastError));
      CloseDeskTop(DsktpHandle);
      exit;
    end;  

  end;  

  SwitchDesktop(DsktpHandle);
end;  

procedure TForm1.N3Click(Sender: TObject);
begin
  Close;
end;  

procedure TForm1.N11Click(Sender: TObject);
begin
  if Sender is TMenuItem then
    SwitchToDesktop((Sender as TMenuItem).Tag);
end;  

procedure TForm1.N2Click(Sender: TObject);
begin
  Show;
end;  

procedure TForm1.ApplicationEvents1Minimize(Sender: TObject);
begin
  Hide;
end;  

procedure TForm1.BitBtn2Click(Sender: TObject);
begin
  Hide;
end;  

procedure TForm1.N4Click(Sender: TObject);
begin
  TrayForm.Show;
end;  

procedure TForm1.OnHotKey(var Msg: TMessage);
begin
  if Msg.WParam >0 then
  if Msg.WParam <=4 then
    SwitchToDesktop(Msg.WParam);  

  //if Msg.WParam=5 then
//    TrayIcon1.Visible := not TrayIcon1.Visible;
end;  

procedure TForm1.TrayIcon1DblClick(Sender: TObject);
begin
  Show;
end;  

procedure TForm1.FormCreate(Sender: TObject);
begin
  RegisterHotKey(Handle, 1, MOD_CONTROL, VK_F1);
  RegisterHotKey(Handle, 2, MOD_CONTROL, VK_F2);
  RegisterHotKey(Handle, 3, MOD_CONTROL, VK_F3);
  RegisterHotKey(Handle, 4, MOD_CONTROL, VK_F4);
  RegisterHotKey(Handle, 5, MOD_CONTROL, VK_F5);
end;  

end. 

参考：http://www.cnblogs.com/key-ok/p/3417735.html