How can i exctract data from excel usind asp.net in C# language? and how to compare it with xml document?

you can "read" data from an excel spreadsheet with ado .net, by selecting the odbc provider for ado .net and excel as the datasource. you can then use an asp .net program to display the data. this will not work in a multi-user situation since the data source is not shareable. In that case you want to put the data in sql server, oracle or any other multi-user system.