Difference between DataGrid and Grid View is given below:-

Datagrid..
1.Code requires to handle the SortCommand event and rebind grid required.
2.Code requires to handle the PageIndexChanged.
3.Need extensive code for update operation on data.
4.When compared to gridview less events supported.

Grid View : ..
1.No code required.
2.No code required for PageIndexChanged.
3.Needs little code for update operation.
4.GridView supports events fired before and after database updates

          
            
              In
case, when you are facing colspan problem in datagarid paging section, then use this
code to correcting colspan problem.
            
          
        

          
            protected
            void dGrid_PreRender(object sender,
EventArgs e)         {             try             {
                DataGrid
dgSidDetails = (DataGrid)sender;
                //Fix
for numbering being in a left aligned column                 //For
some reason, the ColumnSpan property is ignored andnot rendered                     //unless
set using the Attributes                     if (dgSidDetails.AllowPaging
== true &&
dgSidDetails.AutoGenerateColumns ==    false)
                    {
                        //Get
the Table                         System.Web.UI.WebControls.Table
tab =                             (System.Web.UI.WebControls.Table)dgSidDetails.Controls[0];
                        //Change
the Top Pager                         if (dgSidDetails.PagerStyle.Position
== PagerPosition.Bottom ||                             dgSidDetails.PagerStyle.Position
== PagerPosition.TopAndBottom)                         {
                            tab.Rows[tab.Rows.Count -                                 1].Cells[0].Attributes.Add("colspan",
                                tab.Rows[1].Cells.Count.ToString());
                        }
                        //Change
the Bottom Pager                         if (dgSidDetails.PagerStyle.Position
== PagerPosition.Top ||                             dgSidDetails.PagerStyle.Position
== PagerPosition.TopAndBottom)                         {
                            tab.Rows[0].Cells[0].Attributes.Add("colspan",
                                tab.Rows[1].Cells.Count.ToString());
                        }
                    }
            }             catch (Exception
ex)             {             }
        }
        

ASP.NET provides the following additional benefits:

Simplified development: ASP.NET offers a very rich object model that developers can use to reduce the amount of code they need to write.

Language independence: ASP pages must be written with scripting. In other words, ASP pages must be written in a language that is interpreted rather than compiled. ASP.NET allows compiled languages to be used, providing better performance and cross-language compatibility.

Simplified deployment: With .NET components, deployment is as easy as copying a component assembly to its desired location.

Cross-client capability: One of the foremost problems facing developers today is writing code that can be rendered correctly on multiple client types. For example, writing one script that will render correctly in Internet Explorer 5.5 and Netscape Navigator 4.7, and on a PDA and a mobile phone is very difficult, if not impossible, and time consuming. ASP.NET provides rich server-side components that can automatically produce output specifically targeted at each type of client.

Web services: ASP.NET provides features that allow ASP.NET developers to effortlessly create Web services that can be consumed by any client that understands HTTP and XML, the de facto language for inter-device communication.

Performance: ASP.NET pages are compiled whereas ASP pages are interpreted. When an ASP.NET page is first requested, it is compiled and cached, or saved in memory, by the .NET Common Language Runtime (CLR). This cached copy can then be re-used for each subsequent request for the page. Performance is thereby improved because after the first request, the code can run from a much faster compiled version.