datagrid的新增问题

Dim cmd As New SqlClient.SqlCommand("select * from t_item where ccode='" & txtitemCode.Text.ToString & "'", conn)
            Dim reader As SqlClient.SqlDataReader = cmd.ExecuteReader
            If reader.Read = True Then
                Cls_Message.ShowMessage("表中已经存在该编号的项目，请重新输入！", Response)
                txtitemCode.Text = ""
                Exit Sub
            End If