将vb 6代码转换为vb.net时出错

Question

运行以下函数时，会发生运行时错误：

Public Sub SelectComboItemByValue(ByRef cboorlstCntrl As Object, ByRef lngItemValue As Long)
    Dim cntrl As Control
    Dim intcounter As Integer

    cntrl = cboorlstCntrl
    For intcounter = 0 To cntrl.list.items.count - 1
        If cntrl.itemdata(intcounter) = lngItemValue Then
            cntrl.selectedindex = intcounter
            Exit For
        End If
    Next
    cboorlstCntrl = cntrl

End Sub

Answer 1

您需要将cntrl声明为ComboBox，并将cboorlstCntrl参数投放到其中，如下所示：

If TypeOf(cboorlstCntrl) Is ComboBox Then
    Dim cntrl As ComboBox = DirectCast(cboorlstCntrl, ComboBox)
    Dim intcounter As Integer

    cntrl = cboorlstCntrl
    For intcounter = 0 To cntrl.Items.Count - 1
        If cntrl.Items(intcounter) = lngItemValue Then
            cntrl.SelectedIndex = intcounter
            Exit For
        End If
    Next
    cboorlstCntrl = cntrl
End If

通过这样做，cntrl将拥有您期望的所有方法，例如.Items属性。顺便说一句，.Items属性将是您要用于获取控件中的项目的属性...组合框没有.List属性。我已更新您的For循环以反映此情况。