I didnt frame my question properly in last post.

1.I want to know how using UltraDatasource with Grid is different from using another Datasources (List,BindingList,Dataset).

2.What are the use case scenarios in which we can use UltraDataSource.

The UltraDataSource has some advantages and disadvantages over the standard DataSet/DataTable.

• The UltraDataSource is useful if your data is not coming from a DataBase and you just want to manually or programmatically create a list of data and bind it to the grid. This is essentially like using the grid unbound. It's not really unbound, because the grid has to have a DataSource of some kind. But the UltraDataSource doesn't rely on any database or back end.You could, of course, create a DataTable in code, as well. But DataTable has support for tracking which records have changed and requires you to commit those changes to the back end, which is not very useful if you don't have a back end.
• Another advantage of UltraDataSource over a DataSet/DataTable is that it's more efficient, especially in terms of displaying hierarchical data. A DataSet has to build the list of child rows for each parent row every time they are requested, because the data is relational. The UltraDataSource child data is not calculated. You create the rows and you create the child rows and assign them to the parent row, so the parent row always knows exactly who it's child rows are. This, of course, can also be a disadvantage, because it's a little more difficult to move a child row from one parent row to another. With a DataTable, you just change the value of the foreign key. With UltraDataSource, you have to remove the original row and add a new one. 
• UltraDataSource also supports a load-on-demand or virtual mode where you can populate it's data by handling events. So you can populate the fields as they are needed instead of populating the whole table up-front like you must do in a DataSet/DataTable. The down side of this is that it requires more coding, and it will be useless if you need to sort or filter the data in the grid, since these operations require you to load all of the data anyway.