Using Explicit Cast instead of Databinder.Eval to Increase Performance

Introduction

The DataBinder.Eval method is used to bind data to a control's template. DataBinder.Eval casts Container.DataItem to its specific type, like this:

<ItemTemplate>
<div>
<%# DataBinder.Eval(Container.DataItem,"UserName") %>
</div> 
</ItemTemplate>  

DataBinder.Eval uses .NET reflection to cast Container.DataItem to its specific type which results in a performance loss. So it is better to use explicit casting.

Option 1 - Cast the Container.DataItem as a DataRowView if the data source is a DataSet.

<ItemTemplate> 
<div><%# ((DataRowView)Container.DataItem)["UserName"] %>
</div>
</ItemTemplate>

Option 2 for DataReader

<ItemTemplate>
<div>
<%# ((DbDataRecord)Container.DataItem)["UserName"] %>
</div>
</ItemTemplate> 

Cast the Container.DataItem as a String if the data source is an Array or an ArrayList.

<ItemTemplate>
<div>
<%# ((String)Container.DataItem)["UserName"] %>
</div>
</ItemTemplate>