autocompletecombobox.cpp

来自「VC++编程百例」· C++ 代码 · 共 86 行

// AutoCompleteComboBox.cpp : implementation file
//

#include "stdafx.h"
#include "ACCombo.h"
#include "AutoCompleteComboBox.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CAutoCompleteComboBox

CAutoCompleteComboBox::CAutoCompleteComboBox()
{
	m_bAutoComplete = TRUE;
}

CAutoCompleteComboBox::~CAutoCompleteComboBox()
{
}

BEGIN_MESSAGE_MAP(CAutoCompleteComboBox, CComboBox)
	//{{AFX_MSG_MAP(CAutoCompleteComboBox)
	ON_CONTROL_REFLECT(CBN_EDITUPDATE, OnEditUpdate)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CAutoCompleteComboBox message handlers

BOOL CAutoCompleteComboBox::PreTranslateMessage(MSG* pMsg)
{
	// Need to check for backspace/delete. These will modify the text in
	// the edit box, causing the auto complete to just add back the text
	// the user has just tried to delete. 

	if (pMsg->message == WM_KEYDOWN)
	{
		m_bAutoComplete = TRUE;

		int nVirtKey = (int) pMsg->wParam;
		if (nVirtKey == VK_DELETE || nVirtKey == VK_BACK)
			m_bAutoComplete = FALSE;
	}

	return CComboBox::PreTranslateMessage(pMsg);
}

void CAutoCompleteComboBox::OnEditUpdate() 
{
  // if we are not to auto update the text, get outta here
  if (!m_bAutoComplete) 
      return;

  // Get the text in the edit box
  CString str;
  GetWindowText(str);
  int nLength = str.GetLength();
  
  // Currently selected range
  DWORD dwCurSel = GetEditSel();
  WORD dStart = LOWORD(dwCurSel);
  WORD dEnd   = HIWORD(dwCurSel);

  // Search for, and select in, and string in the combo box that is prefixed
  // by the text in the edit box
  if (SelectString(-1, str) == CB_ERR)
  {
      SetWindowText(str);		// No text selected, so restore what was there before
      if (dwCurSel != CB_ERR)
        SetEditSel(dStart, dEnd);	//restore cursor postion
  }

  GetWindowText(str);

  // Set the text selection as the additional text that we have added
  if (dEnd < nLength && dwCurSel != CB_ERR)
      SetEditSel(dStart, dEnd);
  else
      SetEditSel(nLength, -1);
}