ComboBox控件如何做到Access中ComboBox的自动匹配列表项目？要求代码

意思是：假如我的ComboBox的list中有abcd, abde, acdf等等项目。如果我开始输入a，combobox应当立即显示abcd，并且，bcd是选中状态，以便用户继续输入。如果第二个输入c，则马上显示acdf，并且df是选中状态。我说的combobox是dropdown样式的。

解决方案 »

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---------------------------module1
Public Const LB_FINDSTRING& = &H18F
Public Const CB_FINDSTRINGEXACT& = &H14C
Public Const EM_GETSEL = &HB0
Public Const EM_LINEFROMCHAR = &HC9
Public Const EM_LINEINDEX = &HBB
Public Const CB_GETEDITSEL = &H140
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long------------------------------------form1
Dim ol As Integer
Dim isKeyPressed As Boolean
Dim isKeyBackPressed As Boolean
Dim isAnySelectedChar As Boolean
Dim BackLen As Integer
Dim aStr As String
Dim I As Integer
Dim beforeStr As String
Dim afterStr As String
Dim cursorPos As Long
Dim selLen As Integer'²Ù×ÝComboxµÄÐÐÎª
Private Sub Combo1_Change()
Dim Blen As Integer
Dim pos As Long    afterStr = Combo1.Text'Èç¹û·Ç¹¦ÄÜ¼ü£¨Enter¡¢BackSpace£©°´ÏÂ
If isKeyPressed Then

    ol = Len(Combo1.Text)
    DoEvents
    I = SendMessage(Combo1.hwnd, CB_FINDSTRINGEXACT, -1, ByVal CStr(Combo1.Text))
    If I >= 0 Then
        Combo1.ListIndex = I
        Combo1.SelStart = ol
        Combo1.SelLength = Len(Combo1.Text) - ol
        Combo1.Refresh
    Else
        pos = cursorPos + (Len(afterStr) - (Len(beforeStr) - selLen))
        'pos = FindInsertPos(beforeStr, afterStr)
        Combo1.SelStart = pos
        Combo1.SelLength = 0
    End If
'MsgBox beforeStr & "-" & afterStr
    '·ÀÖ¹OnChangeÊÂ¼þ×Ô¼¤£¨ÓÉÓÚ¸Ä±äÁËComboxµÄÄÚÈÝ£©
    isKeyPressed = False
End If'Èç¹ûBackSpace¼ü°´ÏÂ£¬²Á³ýÎ²²¿×Ö·û
If isKeyBackPressed Then     'aStr = Combo1.Text

     'Èç¹û°´ÏÂBackSpace¼üÖ®Ç°ÓÐ×Ö·ûÑ¡ÖÐ£¬ÇÒÑ¡ÖÐµÄ×Ö·ûÔÚÎ²²¿£¬Í¬Ê±×Ö·û´®³¤¶È²»Ð¡ÓÚ1
     If isAnySelectedChar Then
        If Len(afterStr) >= 1 Then
            afterStr = Left$(afterStr, Len(afterStr) - 1)
        End If
     End If     ol = Len(afterStr)

     DoEvents

     'ÕÒ³öComboxÖÐ×î·ûºÏÊäÈë×Ö´®µÄÏîµÄÏÂ±ê
     I = SendMessage(Combo1.hwnd, CB_FINDSTRINGEXACT, -1, ByVal CStr(afterStr))

     'Èç¹ûÃ»ÕÒµ½
     If I < 0 Then

         pos = cursorPos + (Len(afterStr) - Len(beforeStr))
         'Èç¹ûÉ¾³ýµÄ×Ö·û²»ÔÚÎ²²¿£¬ÉèÖÃ¹â±êÔÚÉ¾³ýÎ»ÖÃ
         If (pos < Len(Combo1.Text)) And (pos > 0) Then
             Combo1.SelStart = pos
             Combo1.SelLength = 0
         Else
             Combo1.ListIndex = I
             Combo1.SelStart = ol
             Combo1.SelLength = Len(Combo1.Text) - ol

             'Èç¹ûÊäÈëµÄ×Ö´®ÒÑ¾Îª¿Õ£¬ÉèÖÃComboxÏÔÊ¾¿Õ
             If Len(afterStr) = 0 Then
                 Combo1.Text = ""
             End If
             Combo1.Refresh
         End If

     'Èç¹ûÕÒµ½£¬Ë¢ÐÂComboxÏÔÊ¾£¬²¢Ñ¡ÖÐ·ÇÊäÈë×Ö´®
     Else
         I = SendMessage(Combo1.hwnd, CB_FINDSTRINGEXACT, -1, ByVal CStr(afterStr))
         Combo1.ListIndex = I

         'Èç¹ûÔÚ°´BackSpace¼üÖ®Ç°ÓÐ×Ö·ûÑ¡ÖÐ£¬ÔòBackSpaceÖ»²Á³ýÁËÑ¡ÖÐµÄ×Ö·û¡£Òò´Ë£¬Ç¿ÖÆ²ÁÈ¥Î²²¿×îºóÒ»¸ö×Ö·û
         'If isAnySelectedChar Then
         '    Combo1.SelStart = ol - 1
         'Else
             Combo1.SelStart = ol
         'End If
         Combo1.SelLength = Len(Combo1.Text) - ol + 1
         Combo1.Refresh
     End If


     '·ÀÖ¹×Ô¼¤
     isKeyPressed = False
     isKeyBackPressed = False
End IfEnd Sub
'²¶»ñÔÚComboxÉÏµÄ¼üÅÌ¶¯×÷
Private Sub Combo1_KeyPress(KeyAscii As Integer)
    Dim obj As Object
    Dim I As Long
    Dim j As Long

    isKeyPressed = True
    cursorPos = GetCaretPos(Me.ActiveControl.hwnd, I, j)

    'Èç¹ûEnter¼ü°´ÏÂ£¬Ê§È¥½¹µã
    If KeyAscii = vbKeyReturn Then
       Set obj = FindNextControl(Me.ActiveControl.TabIndex)
       If Not (obj Is Nothing) Then obj.SetFocus
       Exit Sub
    End If

    'Èç¹ûBackSpace£¨»ØÍË¼ü£©°´ÏÂ£¬²Á³ý×îºóÒ»¸ö×Ö
    If KeyAscii = vbKeyBack Then
        isKeyPressed = False
        isKeyBackPressed = Not isKeyPressed
    End If

    'ÉèÖÃ¡°ÔÚBackSpace¼ü°´ÏÂÖ®Ç°£¬ÊÇ·ñÓÐÑ¡ÖÐµÄ×Ö·û¡±£¬Í¬Ê±¼ì²éÊÇ·ñÑ¡ÖÐµÄÊÇÖÐ¼äµÄ×Ö·û
    If Combo1.SelLength > 0 Then
        isAnySelectedChar = True
        selLen = Combo1.SelLength
        cursorPos = cursorPos - selLen
    Else
        isAnySelectedChar = False
        selLen = 0
    End If
    beforeStr = Combo1.Text
End Sub
'ÕÒ³öÏÂÒ»¸ö¿ÉÒÔ»ñµÃ½¹µãµÄ¿Ø¼þ
Private Function FindNextControl(ByVal tIndex As Integer) As Control
    Dim obj As Control
    Dim tempIndex As Integer
    Dim tempControl As Control

    For Each obj In Me.Controls
        If obj.TabIndex > tIndex Then
            Set tempControl = obj
            Exit For
        End If
        If obj.TabIndex < tempIndex Then
            tempIndex = obj.TabIndex
            Set tempControl = obj
        End If
    Next
    Set FindNextControl = tempControl
End FunctionPrivate Function FindInsertPos(ByVal bStr As String, ByVal aStr As String) As Integer
    Dim m As Integer
    Dim n As Integer
    Dim j As Integer
    Dim k As Integer
    Dim l As Integer

    m = Len(aStr)
    n = Len(bStr)
    k = m
    l = 0    For j = 1 To IIf(m > n, n, m)
        If Left$(aStr, j) <> Left$(bStr, j) Then
            k = j
            Exit For
        End If
    Next
    If Not isKeyBackPressed Then
        For j = k + 1 To m
            If Left$(aStr, j) = Left$(bStr, k + 1) Then
                l = j - 1
                Exit For
            End If
        Next
        If l <> 0 Then k = l
    End If

    FindInsertPos = k
End Function
Private Sub Form_Load()
    Combo1.Clear
    Combo1.AddItem "Apples"
    Combo1.AddItem "Appies"
    Combo1.AddItem "Banana"
    Combo1.AddItem "Bread"
    Combo1.AddItem "Break"
    Combo1.AddItem "Bxuu"
    Combo1.AddItem "Bxv1"
    Combo1.AddItem "Bybb"
    Combo1.AddItem "Bybb"
    Combo1.AddItem "»ÆÊ¯ÈË"
    Combo1.AddItem "»Æ¹âÏÀ"
    Combo1.AddItem "ÀîÈôÊ¯"

End SubPublic Function GetCaretPos(ByVal hwnd5 As Long, sPos As Long, ePos As Long) As Long
Dim I As Long
    I = SendMessage(hwnd5, CB_GETEDITSEL, sPos, ePos)
    GetCaretPos = ePos
End Function
有些测试代码，请参考