Create a dropdown that filters the output of my repeater - asp.net

Question

I have a repeater that lists all the products in my Products table and I need a dropdown box to filter the repeater content by category_id. I have absolutely no idea what I'm doing. Here is my repeater:
<asp:Repeater ID="RShopItems" runat="server" ItemType="WebDevAssessment.Models.Product">
<ItemTemplate>
<div class="col-md-4 productOuterContainer">
<div class="col-md-10 col-md-offset-1 productInnerContainer border">
<a href='<%#"ProductDetails.aspx?item=" + Item.product_id %>' runat="server" target="_parent">
<img runat="server" alt='<%# Item.product_name %>' src='<%# Item.product_image1 %>'
style="width: 100%" class="img-thumbnail" />
</a>
<h4 class="text-center"><%# Item.product_name %></h4>
<p class="text-center">Size: <%#Item.product_size%> - $<%#Item.product_price%></p>
<p class="features_text text-center"><%#Item.product_feat_short%></p>
</div>
</div>
</ItemTemplate>
</asp:Repeater>
And the behind code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using WebDevAssessment.Models;
namespace WebDevAssessment
{
public partial class Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
using (WebDatabaseEntities wde = new WebDatabaseEntities())
{
var products = (from si in wde.Products
orderby si.product_price descending
select si).ToList();
// assign the data to the repeater
RShopItems.DataSource = products;
// trigger the repeater to incorporate to display the data
RShopItems.DataBind();
}
}
}
}

Answer 1

Ok, you can use this apporach.
In this example, we have a repeater - showing hotel names.
We have a drop down list to filter by city (no choice = all cities).
So, the mark up looks like this:
<asp:DropDownList ID="DropDownList1" runat="server" DataTextField="City" DataValueField="ID" AutoPostBack="True">
</asp:DropDownList>
<br />
<br />
<asp:Repeater ID="Repeater1" runat="server">
<ItemTemplate>
<div style="border-style:solid;color:black;width:250px;float:left">
<div style="padding:5px;text-align:right">
Hotel Name: <asp:TextBox ID="txtHotelName" runat="server" Text ='<%# Eval("HotelName") %>' Width="130px" />
<br />
First Name: <asp:TextBox ID="txtFirst" runat="server" Text ='<%# Eval("FirstName") %>' Width="130px" />
<br />
Last Name: <asp:TextBox ID="txtLast" runat="server" Text ='<%# Eval("LastName") %>' Width="130px" />
<br />
City: <asp:TextBox ID="txtCity" runat="server" Text ='<%# Eval("City") %>' Width="130px" />
<br />
</div>
</div>
</ItemTemplate>
</asp:Repeater>
And the code to load up drop, load up Repeater, and filter looks like this:
protected void Page_Load(object sender, System.EventArgs e)
{
if (IsPostBack == false)
{
LoadDropDown();
LoadGrid();
}
}
public void LoadDropDown()
{
// load drop down list
using (SqlCommand cmdSQL = new SqlCommand("SELECT ID, City from tblCity ORDER BY City",
new SqlConnection(My.Settings.TEST3)))
{
cmdSQL.Connection.Open();
DropDownList1.DataSource = cmdSQL.ExecuteReader;
DropDownList1.DataBind();
// add blank row choice to drop down list
DropDownList1.Items.Insert(0, new ListItem(string.Empty, string.Empty));
}
}
public void LoadGrid(string sFilter = "")
{
using (SqlCommand cmdSQL = new SqlCommand("SELECT * FROM tblHotels",
new SqlConnection(My.Settings.TEST3)))
{
if (sFilter != "")
{
cmdSQL.CommandText += " WHERE City = #City";
cmdSQL.Parameters.Add("#City", SqlDbType.NVarChar).Value = DropDownList1.SelectedItem.Text;
}
cmdSQL.CommandText += " ORDER BY HotelName";
cmdSQL.Connection.Open();
Repeater1.DataSource = cmdSQL.ExecuteReader;
Repeater1.DataBind();
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
LoadGrid(DropDownList1.SelectedItem.Text);
}
So it now looks like this:
So, on first load - you load up the dropdown, and the repeater.
Dropdown list has auto post back = true, and it simply filters the Repeater by applying a parameters (optional) to the data source for the repeater.
It not a lot of code, and I don't see any advantages to using linq as you are.