Join, Intersec, Expect options on Data Table / Dataset using LINQ

/*

1. Querying DataTable using Linq 

    Here i am going to explain how you can use linq to get data from DataTable.

    You need to use AsEnumerable() method of DataTable object to query datatable using linq.

*/

//Example :  

DataTable dt = new DataTable();

dt.Columns.Add("ID");

dt.Columns.Add("Name");

DataRow dr = dt.NewRow();

dr["ID"] = "1";

dr["Name"] = "Test1";

dt.Rows.Add(dr);

dr = dt.NewRow();

dr["ID"] = "2";

dr["Name"] = "Test2";

dt.Rows.Add(dr);

var result = from user in dt.AsEnumerable()

                     where user.Field<string>("ID") == "1"

                     select user;

/*

2. Join Two DataTable using Linq.

     Example : Here i take two datatables.

*/

        DataTable dt = new DataTable();

        dt.Columns.Add("ID");

        dt.Columns.Add("Name");

        DataRow dr = dt.NewRow();

        dr["ID"] = "1";

        dr["Name"] = "Test1";

        dt.Rows.Add(dr);

        dr = dt.NewRow();

        dr["ID"] = "2";

        dr["Name"] = "Test2";

        dt.Rows.Add(dr);

        DataTable dt1 = new DataTable();

        dt1.Columns.Add("ID");

        dt1.Columns.Add("Product");

        dr = dt1.NewRow();

        dr["ID"] = "1";

        dr["Product"] = "Test-Product";

        dt1.Rows.Add(dr);

//Linq Query:

            var c = from p in dt.AsEnumerable()

            join d in dt1.AsEnumerable() on p.Field<string>("ID") equals d.Field<string>("ID")

            select new { ID = p.Field<string>("ID"), Name = p.Field<string>("Name"), Product = d.Field<string>("Product") };

/*

3. Except and Intersect operation between two DataTable using Linq .

*/

        DataTable dt = new DataTable();

        dt.Columns.Add("ID");

        dt.Columns.Add("Name");

        DataRow dr = dt.NewRow();

        dr["ID"] = "1";

        dr["Name"] = "Test1";

        dt.Rows.Add(dr);

        dr = dt.NewRow();

        dr["ID"] = "2";

        dr["Name"] = "Test2";

        dt.Rows.Add(dr);

        DataTable dt1 = new DataTable();

        dt1.Columns.Add("ID");

        dt1.Columns.Add("Name");

        dr = dt1.NewRow();

        dr["ID"] = "1";

        dr["Name"] = "Test1";

        dt1.Rows.Add(dr);

        var  exceptresult = dt.AsEnumerable().Except(dt1.AsEnumerable(), System.Data.DataRowComparer.Default);

         var intersectresult  = dt.AsEnumerable().Intersect(dt1.AsEnumerable(), System.Data.DataRowComparer.Default);

/*

For both of above operation you need to specify DataRowComparer . System.Data.DataRowComparer is a static sealed class and its static property Default contain comparer reference.  You must have to specify comparer for this operation on Reference datatype.

*/