小编Pra*_*nth的帖子

我无法绑定edititem模板中的下拉列表.当我尝试访问它时,我得到空引用.

我的设计:

<asp:TemplateField HeaderText ="Category">
    <ItemTemplate >
    <asp:Label ID="drpcategory" Text ='<%#Bind("category") %>' runat ="server" />
    </ItemTemplate>
    <EditItemTemplate>
        <asp:DropDownList ID="drpcategory1"  AppendDataBoundItems="True" runat="server" >
        </asp:DropDownList>
    </EditItemTemplate>
</asp:TemplateField> 

我的代码背后:

protected void gv_RowEditing(object sender, GridViewEditEventArgs e)
{
    gv_table1.EditIndex = e.NewEditIndex;
    DropDownList drpcategory1 = ((DropDownList)gv_table1.Rows[e.NewEditIndex].Cells[8].FindControl("drpcategory1"));
    //BindDropDown(drpcategory1);
    dt = con.GetData("Select category_name from category");

    String str = gv_table1.Rows[e.NewEditIndex].FindControl("drpcategory1").GetType().ToString();
    //((DropDownList)gv_table1.Rows[e.NewEditIndex].Cells[8].FindControl("drpcategory1")).DataSource = dt;
    drpcategory1.DataSource = dt;
    drpcategory1.DataTextField = "category_name";
    drpcategory1.DataValueField = "category_name";
    drpcategory1.DataBind();

    this.setgrid();
}

我试过在网上看,试了很多东西是徒劳的.我是asp新手.提前致谢.我希望只有当用户进入编辑模式时才会绑定下拉列表.

我对asp.net比较陌生，所以如果我的查询幼稚我的网格设计，请耐心等待：

<asp:GridView runat ="server"  GridLines = "Both" DataKeyNames="book_id"AutoGenerateColumns ="false" CellPadding ="5" CellSpacing ="5" allowpaging="True" allowsorting="True"
 ID="gv_table1" EmptyDataText ="No data exists"       OnRowEditing="gv_RowEditing"
OnRowCancelingEdit="gv_RowCancelingEdit" OnRowUpdating="gv_RowUpdating" OnRowDeleting="gv_RowDeleting">
    <Columns>

<asp:BoundField HeaderText="Book ID"  DataField="book_id">

</asp:BoundField>



<asp:BoundField DataField="book_name"   HeaderText="Book Name">

</asp:BoundField>
<asp:BoundField DataField="author_name" HeaderText="Author Name">

</asp:BoundField>
<asp:BoundField DataField="publisher" HeaderText="Publisher">

</asp:BoundField>
<asp:BoundField DataField="year_edition" HeaderText="Year/Edition">

</asp:BoundField>
<asp:BoundField DataField="total_no" HeaderText="Total No">

</asp:BoundField>
<asp:BoundField DataField="available" HeaderText="Available">

</asp:BoundField>
<asp:BoundField DataField="tags" HeaderText="Tags">

</asp:BoundField>
<asp:BoundField DataField="fare" HeaderText="Fare">

</asp:BoundField>
<asp:BoundField DataField="state" HeaderText="State">

</asp:BoundField>
 <asp:templatefield HeaderText ="Options">
                                <itemtemplate >

                                        <asp:linkbutton id="btnEdit" runat="server" commandname="Edit" text="Edit" /> …