帮我看一下代码，谢谢

请问，我用了itablesort接口，查出来的数据有重复，怎么才能让它唯一。代码如下：
Dim pFeatureClass As IFeatureClass
'Set pLayer = Main.g_pStateLayer
Set pFeatureClass = pLayer.FeatureClass
' (2) Sort State layer's table
Dim pTableSort As ITableSort
Set pTableSort = New TableSort
pTableSort.Fields = "cm"
pTableSort.Ascending("cm") = True
Set pTableSort.Table = pFeatureClass
pTableSort.Sort Nothing
'
' (3) Populate the State's combo box
Dim pCursor As ICursor
Dim pRow As IRow

Dim lngFieldIndex As Long
Set pCursor = pTableSort.Rows
'Set pCursor = pTableSort.SortCharacters
lngFieldIndex = pFeatureClass.FindField("cm")
Set pRow = pCursor.NextRow
Do While Not pRow Is Nothing
cm.AddItem pRow.Value(lngFieldIndex)
Set pRow = pCursor.NextRow
Loop