原文：

发现原程序有一个问题，ComboBox本身无法截获PreTranslateMessage。

 

为了要获取键盘按下的消息，可以从ComboBox里面的Edit下手，获取Edit的WM_KEYDOWN消息，再交给Edit的父窗口ComboBox处理。代码：

1: //*************************************************************************

2: //

3: // Copyright (C), 2009-2010, Handy Information Co.,Ltd,All Rights Reserved

4: //

5: // FileName:      AutoComboBox.h

6: // Author:        yinxf

7: // Date:          2012/2012/3

8: // Description:   自动完成ComboBox

9: // Function List:

10: // History:

11: //          
            
                
      
    

12: //            yinxf          2010/07/13        Build

13: //

14: //*************************************************************************

15: #pragma once

16:

17: class CAutoComboBox

18:     : public CWindowImpl
    

19: {

20: public:

21:     DECLARE_WND_SUPERCLASS(_T("AutoComboBox"), GetWndClassName())

22:

23:     CAutoComboBox(void)

24:         : m_Edit(this, 1)// 调用CContainedWindowT构造函数,告诉CEdit处理ALT_MSG_MAP的1小节

25:         , m_bAutoComplete(TRUE)

26:     {

27:     }

28:     ~CAutoComboBox(void){}

29:

30: protected:

31:     BEGIN_MSG_MAP(CAutoComboBox)

32:         REFLECTED_COMMAND_CODE_HANDLER_EX(CBN_EDITUPDATE, OnEditUpdate)

33:         DEFAULT_REFLECTION_HANDLER()

34:     ALT_MSG_MAP(1)      // 添加ALT_MSG_MAP消息处理

35:         MESSAGE_HANDLER(WM_KEYDOWN, OnKeyDown)

36:     END_MSG_MAP()

37:

38:     BOOL SubclassWindow(HWND hWnd)

39:     {

40:         POINT pt;

41:         pt.x = 3;

42:         pt.y = 3;

43:         HWND hwndEdit = ::ChildWindowFromPoint(hWnd , pt);

44:         m_Edit.SubclassWindow( hwndEdit );  // 将变量与CEdit控件关联

45:

46:         BOOL bRet = __super::SubclassWindow(hWnd);

47:         return bRet;

48:     }

49:

50:     // CBN_EDITUPDATE 输入框中内容被更新

51:     LRESULT OnEditUpdate(UINT uNotifyCode, int nID, CWindow wndCtl)

52:     {

53:         if (!m_bAutoComplete)

54:             return 0;

55:

56:         CString str;

57:         GetWindowText(str);

58:         int nLength = str.GetLength();

59:

60:         // Currently selected range

61:         DWORD dwCurSel = GetEditSel();

62:         WORD dStart = LOWORD(dwCurSel); // 编辑控件中选中的字符串中起始位置

63:         WORD dEnd   = HIWORD(dwCurSel); // 紧接着选中的字符串的第一个字符的位置

64:

65:         // Search for, and select in, and string in the combo box that is prefixed

66:         // by the text in the edit box

67:         // 从列表开始查找并选中包含指定字符串的行

68:         if ( SelectString(-1, str) == CB_ERR )

69:         {

70:             SetWindowText(str);        // No text selected, so restore what was there before

71:             if (dwCurSel != CB_ERR)

72:                 SetEditSel(dStart, dEnd);    //restore cursor postion

73:         }

74:

75:         // Set the text selection as the additional text that we have added

76:         if ( dEnd < nLength && dwCurSel != CB_ERR )

77:             SetEditSel(dStart, dEnd);

78:         else

79:             SetEditSel(nLength, -1);

80:

81:         SetMsgHandled(FALSE);

82:         return 0;

83:     }

84:

85:     // Need to check for backspace/delete. These will modify the text in

86:     // the edit box, causing the auto complete to just add back the text

87:     // the user has just tried to delete.

88:     LRESULT OnKeyDown(UINT /*uMsg*/, WPARAM wParam, LPARAM /*lParam*/, BOOL& bHandled)

89:     {

90:         m_bAutoComplete = TRUE;

91:

92:         if ( wParam == VK_DELETE || wParam == VK_BACK )

93:         {

94:             m_bAutoComplete = FALSE;

95:         }

96:

97:         bHandled = FALSE;

98:         return 0;

99:     }

100:

101: protected:

102:     BOOL m_bAutoComplete;

103:     CContainedWindowT
    
      m_Edit;        // CContainedWindow包容器窗口, 在控件的父窗口中处理控件的消息
    

104: };