主题：流水帐公式

流水账：余额=收入-支出

DataColChanged代码哪里错了？
Dim i As Integer
If e.DataCol.Name = "收入" OrElse e.DataCol.Name = "支出" Then
    For Each dr As DataRow In e.DataTable.DataRows
        dr(0)("余额") = dr(0)("收入")-dr(0)("支出")
        For i = 1 to e.DataTable.DataRows.Count-1
            dr(i)("余额") = dr(i-1)("余额")+dr(i)("收入")-dr(i)("支出")
        Next
    Next
End If