问用复选框在GridView中选择多行:程序不拉数据

EN

<asp:GridView ID="grdEquipment" runat="server" AutoGenerateColumns="false" ShowHeaderWhenEmpty="true" CssClass="table table-bordered">
    <Columns>
        <asp:TemplateField HeaderText="Select">
            <ItemTemplate>
                <asp:CheckBox ID="chkMultiSelect_Out" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField HeaderText="Equipment Name" DataField="Name" />
        <asp:BoundField HeaderText="Category" DataField="Category.Name" />
    </Columns>
    <EmptyDataTemplate>
        There is no equipment to display.
    </EmptyDataTemplate>
</asp:GridView>
<div class="well">
    <asp:Button ID="btnCheckOut" runat="server" CssClass="btn btn-small btn-inverse" Text="Check Out" OnClick="btnCheckOut_Click" />
</div>

protected void btnCheckOut_Click(object sender, EventArgs e)
    {
        int checkoutNumber = 0;
        //string id = (sender as Button).Attributes["data-id"].ToString();

        SortedBindingList<Tracker.Business.Equipment> eqList = Tracker.Business.EquipmentList.FetchAll();

        foreach (GridViewRow row in this.grdEquipment.Rows)
        {
                CheckBox chkMultiSelect_Out = (CheckBox)row.FindControl("chkMultiSelect_Out") ;
                if (chkMultiSelect_Out.Checked)
                {
                    checkoutNumber++;
                    Tracker.Business.Equipment equip = Tracker.Business.Equipment.GetByIdentification(Int32.Parse(row.ID.ToString()));
                    eqList.Add(equip);
                }

        }

        //If checkoutNumber is 0, do nothing.
        //If checkoutNumber is 1, launch popup for only 1 item
        //If checkoutNumber is more than 1, launch popup for multiple items.
        if (checkoutNumber == 0)
        {
            Response.Redirect("~/Equipment/CheckInOut/Default.aspx");
        }
        else if (checkoutNumber == 1)
        {

        }
        else if (checkoutNumber > 1)
        {

        }
    }