A Datagrid, Datalist are ASP.NET data Web controls.

They have many things in common like DataSource Property , 
DataBind Method ItemDataBound and ItemCreated .

When you assign the DataSource Property of a Datagrid to a 
DataSet then each DataRow present in the DataRow Collection 
of  DataTable is assigned to a corresponding DataGridItem 
and this is same for the rest of the two controls also.

But The HTML code generated for a Datagrid has an HTML 
TABLE <ROW>  element created for the particular DataRow and 
its a Table form representation with Columns and Rows.

For a Datalist its an Array of Rows and based on the 
Template Selected and the RepeatColumn Property value We 
can specify how many DataSource records should appear per 
HTML <table>  row.


In addition to these , Datagrid has a inbuild support for 
Sort,Filter and paging the Data ,which is not possible when 
using a DataList and for a Repeater Control we would 
require to write an explicit code to do paging.