请问各位大侠，如何实现以下功能：
现有combo1和combo2两个组合框，combo1中有值“一”和“二”，当选中“一”时，combo2下拉框中显示a.xls表sheet1中第1列值；当选中“二”时combo2下拉框显示a.xls表sheet1中第2列值。

请问下面代码中的红色部分应该如何修改？如果用循环语句或case语句应该如何写？谢谢！

Option Explicit
Private Sub Form_Load()
  Dim xlsapp As Excel.Application
  Dim xlsworkbook As Excel.Workbook
  Dim xlssheet As Excel.Worksheet
  Combo1.AddItem "一"
  Combo1.AddItem "二"
  Set xlsapp = CreateObject("excel.application")
  Set xlsworkbook = xlsapp.Workbooks.Open(App.Path & "\a.xls")
  xlsapp.Visible = False
      Set xlssheet = xlsworkbook.Worksheets.Item(1)
      Dim h As Integer, l As Integer
      h = xlssheet.UsedRange.Rows.Count
      l = xlssheet.UsedRange.Columns.Count
      Dim i As Integer, j As Integer

    If Combo1.Text = "一" Then
      Combo2.Clear
      For i = 1 To h
        Combo2.AddItem xlssheet.Cells(i, 1)
      Next i
      Combo2.ListIndex = 0
    ElseIf Combo1.Text = "二" Then
      Combo2.Clear
      For j = 1 To h
        Combo2.AddItem xlssheet.Cells(j, 2)
      Next j
      Combo2.ListIndex = 0
    End If
  
  xlsapp.Quit
  Set xlssheet = Nothing
  Set xlsworkbook = Nothing
  Set xlsapp = Nothing
      
End Sub

[ 本帖最后由 桃源书生 于 2009-11-19 22:41 编辑 ]

select case Combo1.Text
   case ""
      代码

   case ""
      代码


  ……
end select

有用

Option Explicit

Private Sub Form_Load()
  Combo1.AddItem "一"
  Combo1.AddItem "二"
End Sub

Private Sub Combo1_Click()
  Dim xlsapp As Excel.Application
  Dim xlsworkbook As Excel.Workbook
  Dim xlssheet As Excel.Worksheet
  Set xlsapp = CreateObject("excel.application")
  Set xlsworkbook = xlsapp.Workbooks.Open(App.Path & "\a.xls")
  xlsapp.Visible = False
      Set xlssheet = xlsworkbook.Worksheets.Item(1)
      Dim h As Integer, l As Integer
      h = xlssheet.UsedRange.Rows.Count
      l = xlssheet.UsedRange.Columns.Count
      Dim i As Integer, j As Integer

    If Combo1.Text = "一" Then
      Combo2.Clear
      For i = 1 To h
        Combo2.AddItem xlssheet.Cells(i, 1)
      Next i
      Combo2.ListIndex = 0
    ElseIf Combo1.Text = "二" Then
      Combo2.Clear
      For j = 1 To h
        Combo2.AddItem xlssheet.Cells(j, 2)
      Next j
      Combo2.ListIndex = 0
    End If
  
  xlsapp.Quit
  Set xlssheet = Nothing
  Set xlsworkbook = Nothing
  Set xlsapp = Nothing

End Sub