unable access the inner nested datalist

Question

in my web application , there is datalist, which is inside another datalist. i want to access that datalist . for this purpose i written this code

DataList dl = (DataList)dlPro_Details.FindControl("dlFeatures");

but when i try to run the application , then it throw Object reference not set to an instance of an object. then set the debug the point to it , the i found my object dl is null .

i have also tried to use ItemDataBound

protected void dlPro_Details_ItemDataBound(object sender, DataListItemEventArgs e)
    {
        int id = 8;
        string getFeatures = "";
        con = new SqlConnection(str);
        con.Open();
        SqlCommand cmd2 = new SqlCommand("select * from Products where Pro_id=" + id + "", con);

        SqlDataReader dr = cmd2.ExecuteReader();
        while (dr.Read())
        {
            getFeatures = dr.GetValue(11).ToString();
        }
        string se = ",";
        List<string> l1 = new List<string>();
        string[] featurs = getFeatures.Split(se.ToCharArray());
        for (int i = 0; i < featurs.Length; i++)
        {
            l1.Add(featurs[i]);
        }
        DataList dl = (DataList)dlPro_Details.FindControl("dlFeatures");

        dl.DataSource = l1;
        dl.DataBind();
    }

dlPro_Details is my parent datalist

this is my complete code

<asp:DataList ID="dlPro_Details" runat="server" OnItemDataBound="dlPro_Details_ItemDataBound">
                    <ItemTemplate>
                        <table>
                            <tr>
                                <td>
                                    <div class="pro_img">
                                        <asp:Image ID="proImg" runat="server" Width="230" Height="300" ImageUrl='<%#Eval("Image") %>' />
                                    </div>
                                    <div class="rating">
                                        give rate<br />hello
                                    </div>
                                </td>
                                <td style="vertical-align:top">
                                    <div class="Pro_name">
                                        <asp:Label ID="lbl" runat="server" Text='<%#Eval("Name") %>' Font-Bold="True"></asp:Label>
                                    </div>
                                    <div class="otherInfo">
                                      <table style="width:100%;padding:8px 12px 0 12px;">
                                          <tr>
                                              <td>
                                                  <asp:Label ID="lblWarenty" runat="server" Text='<%#"Warranty :  "+Eval("Warranty") %>'></asp:Label>
                                              </td>
                                              <td>
                                                  <asp:Label ID="lblBrand" runat="server" Text='<%#"By :  "+Eval("Brand") %>'></asp:Label>
                                              </td>
                                              <td style="float:right">
                                                  Rating 
                                              </td>
                                          </tr>
                                      </table>
                                    </div>
                                    <div class="features">
                                       <div class="feat_Head">
                                           <asp:Label ID="lblFeatHead" runat="server" Text="Features"></asp:Label>
                                       </div>
                                        <div class="feat_containt">
                                            <asp:DataList ID="dlFeatures" runat="server" RepeatColumns="5" RepeatDirection="Vertical">
                                                <ItemTemplate> 
                                                    <asp:Label ID="lblFeatures" runat="server" Text="Label"></asp:Label>
                                                </ItemTemplate>
                                            </asp:DataList>
                                        </div>
                                    </div>
                                </td>
                            </tr>
                        </table>
                    </ItemTemplate>
                </asp:DataList>

Answer 1

You will find the reference to the current item using one of the arguments, and from there you can access any nested control:

protected void dlPro_Details_ItemDataBound(object sender, DataListItemEventArgs e)
{
    if(e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
    {
        var innerDL = e.Item.FindControl("dlFeatures") as DataList;
        if(innerDL != null)
        {
            //do something
        }
    }
}