主题：Relations是否不能对通过SQLCommand生成的表使用

Dim dt As DataTable = args(0)
Dim str() As String = args(1)
Dim pgl As String = dt.name & "yl"   

    If Relations.Contains(pgl) = True Then '如果已经存在关联
        Relations.Delete(pgl)
    End If
    Dim cmd As new SQLCommand
    cmd.ConnectionName = vars("maindata")
    cmd.CommandText = "s elect [_Identify],物料号,品名,规格参数,工序,封装,品牌,误差 fro m {sf_raw} where [_Identify] is not null"
    Dim ds As DataTable = cmd.ExecuteReader(True)
    If dt.DataCols.Contains("编码") And ds.DataCols.Contains("物料号") Then
       
        Relations.Add(pgl,ds.DataCols("物料号"),dt.DataCols("编码"),False,RelationPathEnum.none)

        msgbox(pgl)
    Else
        msgbox("父表或子表找不到关键列!")
    End If