DataBinder.Eval

Controls such as GridView and Repeater work with templates. A popular way to refer to fields within templates uses DataBinder.Eval, as shown in the following code:

<asp:Repeater ID="rptrEval" runat="server">
<ItemTemplate>
<%# Eval("field1")%>
<%# Eval("field2")%>
<%# Eval("field3")%>
<%# Eval("field4")%>
</ItemTemplate>
</asp:Repeater>

However, this uses reflection to arrive at the value of the field. If you have 10 rows with four fields each, you execute Eval 40 times.

A much faster way is to refer directly to the class that contains the field:

<asp:Repeater ID="rptrCast" runat="server">
<ItemTemplate>
<%# ((MyClass)Container.DataItem).field1 %>
<%# ((MyClass)Container.DataItem).field2 %>
<%# ((MyClass)Container.DataItem).field3 %>
<%# ((MyClass)Container.DataItem).field4 %>
</ItemTemplate>
</asp:Repeater>

In this example, I have used class MyClass. If you're binding against a...