主题：跨表引用逻辑问题

If e.DataRow("款项类别") <> "代理费"  And e.DataRow("款项类别") <> "保险费" Then
    If  e.DataRow("付款金额") >= "30000"  Then

        If  e.DataCol.Name = "供货方名称" OrElse e.DataCol.Name = "付款金额" Then
            Dim nms()As String = {"供货方账号","供货方开户银行"}
            If  e.DataRow.isnull("供货方名称") Then
                For Each nm As String In nms
                    e.DataRow(nm)= Nothing
                Next
            Else
                Dim cmd As New SQLCommand
                Dim dt As DataTable
                cmd.C
                cmd.CommandText = "S ELECT DISTINCT 供货方名称,供货方账号,供货方开户银行 From {采购合同管理} where [供货方名称]= '" & e.DataRow("供货方名称") & "'"
                dt = cmd.ExecuteReader()
                If dt.datarows.count > 0 Then
                    Dim dr As DataRow = dt.datarows(0)
                    For Each nm As String In nms
                        e.DataRow(nm)= dr(nm)
                    Next
                    e.DataRow("是否签订采购合同") = True
                Else
                    e.DataRow("供货方名称") = Nothing
                    e.DataRow("是否签订采购合同") = False
                    MessageBox.Show("该供应商还未签订供应合同,不能办理委托支付事宜!","提示",MessageBoxButtons.OK,MessageBoxIcon.None)
                    Return
                End If
            End If
        End If
    Else
        Dim nmw()As String = {"供货方账号","供货方开户银行"}
        Dim cmd As New SQLCommand
        Dim dt As DataTable
        cmd.C
        cmd.CommandText = "S ELECT DISTINCT 供货方名称,供货方账号,供货方开户银行 From {采购合同管理} where [供货方名称]= '" & e.DataRow("供货方名称") & "'"
        dt = cmd.ExecuteReader()
        If dt.datarows.count > 0  Then
            Dim dr As DataRow = dt.datarows(0)
            For Each nm As String In nmw
                e.DataRow(nm)= dr(nm)
            Next
        e.DataRow("是否签订采购合同") = True
        End If
    End If
End If