如何在服務（Service）程序中顯示對話框

原文：http://www.vckbase.com/index.php/wv/94php

服務程序（Service）通常是不能和用戶進行交互的，因此他通常是不能顯示窗口的。要和用戶進行交互（如顯示窗口），咱們必須打開用戶WinSta0和desktop,下面的這段代碼就是打開上述兩個，並顯示一個dialog：spa

 
   01. 
   BOOL CServiceModule::ShowMsgDlg(void) 
  
   02. 
   { 
  
   03. 
   HDESK   hdeskCurrent; 
  
   04. 
   HDESK   hdesk; 
  
   05. 
   HWINSTA hwinstaCurrent; 
  
   06. 
   HWINSTA hwinsta; 
  
   07. 
     
   08. 
   hwinstaCurrent = GetProcessWindowStation(); 
  
   09. 
   if (hwinstaCurrent == NULL){ 
  
   10. 
   LogEvent(_T("get window station err")); 
  
   11. 
   return FALSE; 
  
   12. 
   } 
  
   13. 
     
   14. 
   hdeskCurrent = GetThreadDesktop(GetCurrentThreadId()); 
  
   15. 
   if (hdeskCurrent == NULL){ 
  
   16. 
   LogEvent(_T("get window desktop err")); 
  
   17. 
   return FALSE; 
  
   18. 
   } 
  
   19. 
     
   20. 
   //打開winsta0 
  
   21. 
   hwinsta = OpenWindowStation("winsta0", FALSE,                          
  
   22. 
   WINSTA_ACCESSCLIPBOARD   | 
  
   23. 
   WINSTA_ACCESSGLOBALATOMS | 
  
   24. 
   WINSTA_CREATEDESKTOP     | 
  
   25. 
   WINSTA_ENUMDESKTOPS      | 
  
   26. 
   WINSTA_ENUMERATE         | 
  
   27. 
   WINSTA_EXITWINDOWS       | 
  
   28. 
   WINSTA_READATTRIBUTES    | 
  
   29. 
   WINSTA_READSCREEN        | 
  
   30. 
   WINSTA_WRITEATTRIBUTES); 
  
   31. 
   if (hwinsta == NULL){ 
  
   32. 
   LogEvent(_T("open window station err")); 
  
   33. 
     
   34. 
   return FALSE; 
  
   35. 
   } 
  
   36. 
     
   37. 
   if (!SetProcessWindowStation(hwinsta)){ 
  
   38. 
   LogEvent(_T("Set window station err")); 
  
   39. 
     
   40. 
   return FALSE; 
  
   41. 
   } 
  
   42. 
     
   43. 
   //打開desktop 
  
   44. 
   hdesk = OpenDesktop("default", 0, FALSE,                
  
   45. 
   DESKTOP_CREATEMENU | 
  
   46. 
   DESKTOP_CREATEWINDOW | 
  
   47. 
   DESKTOP_ENUMERATE    | 
  
   48. 
   DESKTOP_HOOKCONTROL  | 
  
   49. 
   DESKTOP_JOURNALPLAYBACK | 
  
   50. 
   DESKTOP_JOURNALRECORD | 
  
   51. 
   DESKTOP_READOBJECTS | 
  
   52. 
   DESKTOP_SWITCHDESKTOP | 
  
   53. 
   DESKTOP_WRITEOBJECTS); 
  
   54. 
   if (hdesk == NULL){ 
  
   55. 
   LogEvent(_T("Open desktop err")); 
  
   56. 
     
   57. 
   return FALSE; 
  
   58. 
   } 
  
   59. 
     
   60. 
   SetThreadDesktop(hdesk); 
  
   61. 
     
   62. 
   //到這一步，咱們獲取了和用戶交互（如顯示窗口）的權利 
  
   63. 
   CMsgDlg dlgMsg; 
  
   64. 
   //顯示一個dialog 
  
   65. 
   dlgMsg.DoModal();              
  
   66. 
     
   67. 
   if (!SetProcessWindowStation(hwinstaCurrent)) 
  
   68. 
   return FALSE; 
  
   69. 
     
   70. 
   if (!SetThreadDesktop(hdeskCurrent)) 
  
   71. 
   return FALSE; 
  
   72. 
     
   73. 
   if (!CloseWindowStation(hwinsta)) 
  
   74. 
   return FALSE; 
  
   75. 
     
   76. 
   if (!CloseDesktop(hdesk)) 
  
   77. 
   return FALSE; 
  
   78. 
     
   79. 
   return TRUE; 
  
   80. 
   }