It does not matter that DataBindExtender looks not usual in the ASP.NET. It turns to be so handy that built-in data binding is not considered to be an option.

After a short try, you uderstand that people tried very hard and have invented many controls and methods like ObjectDataSource, FormView, Eval(), and Bind() with outcome, which is very specific and limited.

In contrast DataBindExtender performs:

• Two or one way data binding of any business data property to any control property;
• Converts value before it's passed to the control, or into the business data;
• Validates the value.

See an example:


<bphx:DataBindExtender runat='server'
  EnableViewState='false'
  TargetControlID='Field8'
  ControlProperty='Text'
  DataSource='<%# Import.ClearingMemberFirm %>'
  DataMember='Id'
  Converter='<%# Converters.AsString("XXXXX", false) %>'
  Validator='<%# (extender, value) => Functions.CheckID(value as string) %>'/>

Here, we beside a regualar two way data binding of a property Import.ClearingMemberFirm.Id to a property Field8.Text, format (parse) Converters.AsString("XXXXX", false), and finally validate an input value with a lambda function (extender, value) => Functions.CheckID(value as string).

DataBindExtender works also well in template controls like asp:Repeater, asp:GridView, and so on. Having your business data available, you may reduce a size of the ViewState with EnableViewState='false'. This way DataBindExtender approaches page development to a pattern called MVC.

Recently, we have found that it's also useful to have a way to run a javascript during the page load (e.g. you want to attach some client side event, or register a component). DataBindExtender provides this with OnClientInit property, which is a javascript to run on a client, where this refers to a DOM element:

... OnClientInit='$addHandler(this, "change", function() { handleEvent(event, "Field8"); } );'/>

allows us to attach onchange javascript event to the asp:TextBox.

So, meantime we're very satisfied with what we can achieve with DataBindExtender. It's more than JSF allows, and much more stronger and neater to what ASP.NET has provided.

The sources can be found at DataBindExtender.cs