Auto Completion ComboBox for WTL

原文：http://www.codeproject.com/Articles/4785/Auto-Completion-ComboBox-for-WTL

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: //          <author>        <time>           <desc>        

 12: //            yinxf          2010/07/13        Build

 13: //

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

 15: #pragma once

 16: 

 17: class CAutoComboBox

 18:     : public CWindowImpl<CAutoComboBox, CComboBox>

 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<CEdit> m_Edit;        // CContainedWindow包容器窗口, 在控件的父窗口中处理控件的消息

104: };