.Net Framework Essentials

Data Binding and the Use of Templates

While all web controls can be data bound, only DataGrid, DataList, and Repeater use a template to control the display of data items. In this section, we show you how to perform simple data binding with some common web controls and how to use an HTML template to provide fully customized data-bound controls.

In its simplest form, data binding is the act of binding a control to a data source. Previously, data binding required that an ADO recordset be a data source, which is not too flexible. There was no way to bind, for example, an array or a collection of objects to a control. With ASP.NET, the whole data-binding business is revamped. The only requirement to make your data source bindable to web controls is that your data source implement the System.Collections.ICollection interface. In other words, a bindable data source is a collection of homogeneous objects that the web controls can obtain data items from.

While it is possible to write your own data classes that implement the ICollection interface and bind them to web controls, there exist numerous classes that do this for you, such as Array, ArrayList, DataView, HashTable, Queue, SortedList, and Stack. All you have to do is put your data in these forms, and you can bind your data to web controls.

Here is the simplest form of data binding. In the form file, all we have are two list boxes with ids list0 and list1:

<asp:listbox id="list0" runat="server"></asp:listbox> <asp:listbox id="list1" ...