主题：请教：表达式代码错误

以下表达式代码在绝缘节点列为空值时显示“未将对象引用设置到对象的实例”错误，请教怎么修改

For i As Integer = 0 To Tables("软横跨悬挂节点").Rows.Count-1

    If i = 0 Then

        Dim r As Row = Tables("软横跨悬挂节点").rows(i)

        Dim JYLX As DataRow = DataTables("绝缘节点").Find("[节点类型] = '" & r("绝缘节点") & "'")

        Dim JYZL As Decimal = IIF(r("绝缘节点") Is Nothing ,JYLX("单横总重"),0)

        r("负载计算值") = JYZL       

    End If

Next

明白了，谢谢