Find Combo Item By ID and Reset SelectedIndex

[maps]

Hello Folks i want to get ID of the combobox item and then reset the selected index of that combobox to that item. I populate my Combobox with a list of 56 Districts from an array so, the ID is hidden.
When i call the sub below which calls FindComboItemByID it gives me the error below, so the sub FindComboItemByID has some problem that i seem not to figure out...is there a better way of doing this?

Sub getDistValueByID() 
       Dim strSQL As String = "SELECT DistID FROM tblDistricts WHERE(District='" & Me.cbDistrict.Text & "')"
        Dim strID As String = connMger.LookUp(strSQL)
        FindComboItemByID(Me.cbDistrict, strID)
    End Sub

Public Sub FindComboItemByID(ByVal cbName As ComboBox, ByVal strID As String)
        ' This sub is used to find an Item in a combobox/listbox and
        ' set the selected index of the combo box/listbox to that item
        'On Error Resume Next
        Dim bFound As Boolean
        Dim itemCount As Integer
        Dim lstItem As New ListItem
        itemCount = 0
        While Not bFound Or itemCount <= cbName.Items.Count - 1
            lstItem = CType(cbName.Items(itemCount), ListItem)
            If lstItem.ID = CInt(strID) Then
                cbName.SelectedIndex = itemCount
                bFound = True
            End If
            itemCount += 1
        End While
        If Not bFound Then
            cbName.SelectedIndex = -1
        End If
    End Sub