主题：跨表统计

If e.DataCol.name = "产品名称"
    Dim drs As List (of DataRow) = DataTables("BOM清单").Select("产品名称= '" & e.DataRow("产品名称") & "'")

    e.DataRow("材料成本") = nothing
    For Each dr As DataRow In drs
        Dim dr1 As DataRow =DataTables("物料价格表").find("物料编号= '" & dr("物料编号") & "'")
        e.DataRow("材料成本")+= dr("数量")*dr1("单价")
    Next
End If