ASP.Net DropDownList Error :System.Data.DataRowView does not contain a property with the name itemMaker

dear fellas, 

im having a problem in binding my data.

i have textbox txtbox_maker to input maker.

but then i want to list down all my "maker" in drop down list (ddl_maker)

i try. 

<asp:SqlDataSource ID="SqlBindMaker" runat="server" ConnectionString="<%$ ConnectionStrings:ESConnectionString %>" 
                    SelectCommand="SELECT veq_ID, veq_Maker FROM IS_VesselEquipment WHERE veq_IsDeleted is NULL Order by veq_Maker">
                </asp:SqlDataSource>

and for vb

Protected Sub LoadMaker()
        ddl_maker.DataSource = SqlBindModel()
        ddl_maker.DataTextField = ("item_Maker")
        ddl_maker.DataValueField = ("item_ID")
        ddl_maker.DataBind()

        ddl_maker.Items.Insert(0, New ListItem("-- Choose --", "-1"))

    End Sub

but i got error "System.Data.DataRowView' does not contain a property with the name 'item_Maker'."

can anyone help me where am i wrong?