主题：求解NumericComboBox 一个问题

Dim nn As Integer = e.Form.Controls("NumericComboBox1").Value
Dim tbl As Table = Tables("社员基本信息")
If nn = 0 Then
    tbl.Filter = ""
Else
tbl.Filter = "社员信息_社员ID = nn"
End If

错误所在事件：
详细错误信息：
System.Data.EvaluateException: Cannot find column [nn].
   at System.Data.NameNode.Bind(DataTable table, List`1 list)
   at System.Data.BinaryNode.Bind(DataTable table, List`1 list)
   at System.Data.DataExpression.Bind(DataTable table)
   at System.Data.DataExpression..ctor(DataTable table, String expression, Type type)
   at System.Data.Select..ctor(DataTable table, String filterExpression, String sort, DataViewRowState recordStates)
   at System.Data.DataTable.Select(String filterExpression)
   at Foxtable.O110ll0O0l.set_Filter(String OO010)

为何？哪儿错了？求告知！谢谢