, 0, @SendHokKey, nil, 0, dwThreadID);
end;

end.


补充:
(1)关于更多服务程序的演示程序,请访问以下Url:http://www.torry.net/pages.php?id=226,上面包含了多个演示如何控制和管理系统服务的代码.

(2)请切记:Windows实际上存在多个桌面.例如屏幕传输会出现白屏,可能有两个原因:一是系统处于锁定或未登陆桌面,二是处于屏幕保护桌面.这时候要将当前桌面切换到该桌面才能抓屏.

(3)关于服务程序与桌面交互,还有种动态切换方法.大概单元如下:
unit ServiceDesktop;

interface

function InitServiceDesktop: boolean;
procedure DoneServiceDeskTop;

implementation

uses Windows, SysUtils;

const
DefaultWindowStation = WinSta0;
DefaultDesktop = Default;
var
hwinstaSave: HWINSTA;
hdeskSave: HDESK;
hwinstaUser: HWINSTA;
hdeskUser: HDESK;
function InitServiceDesktop: boolean;
var
dwThreadId: DWORD;
begin
dwThreadId := GetCurrentThreadID;
// Ensure connection to service window station and desktop, and
// save their handles.
hwinstaSave := GetProcessWindowStation;
hdeskSave := GetThreadDesktop(dwThreadId);


hwinstaUser := OpenWindowStation(DefaultWindowStation, FALSE, MAXIMUM_ALLOWED);
if hwinstaUser = 0 then
begin
OutputDebugString(PChar(OpenWindowStation failed + SysErrorMessage(GetLastError)));
Result := false;
exit;
end;

if not SetProcessWindowStation(hwinstaUser) then
begin
OutputDebugString(SetProcessWindowStation failed);
Result := false;
exit;
end;

hdeskUser := OpenDesktop(DefaultDesktop, 0, FALSE, MAXIMUM_ALLOWED);
if hdeskUser = 0 then
begin
OutputDebugString(OpenDesktop failed);
SetProcessWindowStation(hwinstaSave);
CloseWindowStation(hwinstaUser);
Result := false;
exit;
end;
Result := SetThreadDesktop(hdeskUser);
if not Result then
OutputDebugString(PChar(SetThreadDesktop + SysErrorMessage(GetLastError)));
end;

procedure DoneServiceDeskTop;
begin
// Restore window station and desktop.
SetThreadDesktop(hdeskSave);
SetProcessWindowStation(hwinstaSave);
if hwinstaUser <> 0 then
CloseWindowStation(hwinstaUser);
if hdeskUser <> 0 then
CloseDesktop(hdeskUser);
end;

initialization
InitServiceDesktop;
finalization
DoneServiceDesktop;
end.
更详细的演示代码请参看:http://www.torry.net/samples/samples/os/isarticle.zip

(4)关于安装服务如何添加服务描述.有两种方法:一是修改注册表.服务的详细信息都位于HKEY_LOCAL_MACHINE\SYSTEM\ ControlSet001\Services\下面,例如我们刚才那个服务就位于HKEY_LOCAL_MACHINE\SYSTEM\ ControlSet001\Services\DelphiService下.第二种方法就是先用QueryServiceConfig2函数获取服务信息,然后ChangeServiceConfig2来改变描述.用Delphi实现的话,单元如下:

unit WinSvcEx;

interface

uses Windows, WinSvc;

const
//
// Service config info levels
//
SERVICE_CONFIG_DESCRIPTION = 1;
SERVICE_CONFIG_FAILURE_ACTIONS = 2;
//
// DLL name of imported functions
//
AdvApiDLL = advapi32.dll;
type
//
// Service description string
//
PServiceDescriptionA = ^TServiceDescriptionA;
PServiceDescriptionW = ^TServiceDescriptionW;
PServiceDescription = PServiceDescriptionA;
{$EXTERNALSYM _SERVICE_DESCRIPTIONA}
_SERVICE_DESCRIPTIONA = record
lpDescription : PAnsiChar;
end;
{$EXTERNALSYM _SERVICE_DESCR