In older versions of ASP.NET, When we select any row in a GridView or ListView controls, the selection is based on the row index of the page. For example, If we select row no 3 on page 1 and then move to page 2, we will see row no 3 again selected on page 2. which is undesirable.
ASP.NET 4.0 introduces the feature of Persisted Selection. When this feature is enabled, the selected item is based on the row datakey and not row index. For example, in a Grid showing products, i can specify that DataKey for my products is “ISBN”. Hence the rows will now be selected on the basis of ISBN(i.e. Datakey). Which further means that if i select row no 3 in products grid on page 1 and then move to page 2, no row will be selected. But if i again go back to page 1, row 3 will still be selected.
Feature can be enabled/disabled by setting the property EnablePersistedSelection. Also the property DataKeyNames be specified so that DataKey is set for the rows.