asp.net OnPreLoad doesn't fire? - asp.net

Question

I can't figure out why my OnPreLoad function doesn't get fired for search.aspx.cs.
*Update * - OK, I figured out what's causing the problem, but I don't understand why it is a problem. I updated my question.
Here are three relevant files:
// search.aspx -- THIS <select runat="server"> CAUSED ALL the problem
<select runat="server" id="slctCategories">
<asp:Repeater runat="server" ID="optCategories">
<ItemTemplate>
<option value=""></option>
</ItemTemplate>
</asp:Repeater>
</select>
// search.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Configuration;
public partial class search : BTPage
{
protected override void OnPreLoad(EventArgs e)
{
base.OnPreLoad(e);
}
protected void Page_Load(object sender, EventArgs e)
{
}
}
// BTPage.aspx.cs - the file that search.aspx.cs inherits from
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Configuration;
public partial class BTPage : System.Web.UI.Page
{
protected SqlConnection cnx;
protected override void OnPreLoad(EventArgs e)
{
cnx = new SqlConnection(ConfigurationManager.AppSettings["database"]);
cnx.Open();
}
protected override void OnUnload(EventArgs e)
{
cnx.Close();
}
}
What's weird is that the OnUnload DOES get fired. What's going on? Why won't my OnPreLoad fire?
** UPDATE ** - I got my onpreload to fire after I changed <select runat="server"> to <select> in my search.aspx. Someone explain to me why this fixed the problem? I was struggling for hours with this.

Answer 1

There might be something strange with how you are using your select:
<select runat="server" id="slctCategories">
<asp:Repeater runat="server" ID="optCategories">
<ItemTemplate>
<option value=""></option>
</ItemTemplate>
</asp:Repeater>
</select>
You should not be nesting a Repeater inside that tag. I'm actually surprised you don't get a compilation/runtime error due to that.
You note that you found the DropDownList control to use instead. However, the HttpSelectList control also has a similar interface for adding items to it - you don't need an extra list control inside it.
My guess is, since removing that as a server control fixed the problem (which fixes the syntax weirdness), that there is something subtle going on which prevents the normal OnPreLoad from being fired in that syntax.

Answer 2

In BTPage you don't call base.OnPreLoad:
protected override void OnPreLoad(EventArgs e)
{
cnx = new SqlConnection(ConfigurationManager.AppSettings["database"]);
cnx.Open();
}
I don't know why this would prevent the search class overriding the method, though, or what the select has to do with anything. (e.g. it should have worked anyway). But it is generally good practice to call the base method in any overridden method (even ones like this that are there specifically for you to override). You don't know if anything else that is supposed to take place happens in the core Page.OnPreLoad method.