protected void btnshow_Click(object sender, EventArgs e)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("ID", typeof(string));
        dt.Columns.Add("Name", typeof(string));

        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);
        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);
        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", typeof(string));
        dt1.Columns.Add("Product", typeof(string));
        dt1.Columns.Add("price", typeof(Decimal));
        dr = dt1.NewRow();
        dr["ID"] = "1";
        dr["Product"] = "Test-Product_1";
        dr["price"] = "100";
        dt1.Rows.Add(dr);
        dr = dt1.NewRow();
        dr["ID"] = "2";
        dr["Product"] = "Test-Product_2";
        dr["price"] = "200";
        dt1.Rows.Add(dr);
        dr = dt1.NewRow();
        dr["ID"] = "1";
        dr["Product"] = "Test-Product_1";
        dr["price"] = "400";
        dt1.Rows.Add(dr);
        dr = dt1.NewRow();
        dr["ID"] = "2";
        dr["Product"] = "Test-Product_2";
        dr["price"] = "400";
        dt1.Rows.Add(dr);
        dr = dt1.NewRow();
        dr["ID"] = "1";
        dr["Product"] = "Test-Product_1";
        dr["price"] = "700";
        dt1.Rows.Add(dr);
        dr = dt1.NewRow();
        dr["ID"] = "2";
        dr["Product"] = "Test-pallavi_2";
        dr["price"] = "200";
        dt1.Rows.Add(dr);

        //dataGridView1.DataSource = dt;
        //dataGridView2.DataSource = dt1;

        


        var resultTable = from ct in dt.AsEnumerable()
                          join ao in dt1.AsEnumerable()
                          on (string)ct["ID"]
                             equals (string)ao["ID"]
                          select new
                          {
                              Name = (string)ct["Name"],
                              product = (string)ao["Product"],
                              price=(string)ao["price"]
                          };

        var collection = from t1 in dt.AsEnumerable() join t2 in dt1.AsEnumerable() on t1["ID"] equals t2["ID"]
                         select new { ID=t1["ID"],Name = t1["Name"], Group = t2["Product"],price=t2["price"] }; 
        DataTable result = new DataTable("NameGroups");
        result.Columns.Add("ID", typeof(string));
        result.Columns.Add("Name", typeof(string)); 
        result.Columns.Add("Product", typeof(string));
        result.Columns.Add("price", typeof(Decimal));
        foreach (var item in collection) 
        { 
            result.Rows.Add(item.ID,item.Name, item.Group,item.price); 
        }  
     //Array a = resultTable.ToArray();
     //DataTable tab = resultTable;


        //group by on result table with test1 and 
        var grp_q = from i in result.AsEnumerable()
                    group i by new
                    {
                        ID = i["ID"],
                        name = i["Name"],
                        product = i["Product"],
                        price = i["price"]
                    } into cgrp
                    select new
                    {
                        ID = cgrp.Key.ID,
                        name = cgrp.Key.name,
                        product = cgrp.Key.product,
                        price = cgrp.Key.price,
                       total=cgrp.Sum(p=>p.Field<Decimal>("price"))
                        
                      
                    };

        DataTable result1 = new DataTable("NameGroups");
        result1.Columns.Add("ID", typeof(string));
        result1.Columns.Add("Name", typeof(string));
        result1.Columns.Add("Product", typeof(string));
        result1.Columns.Add("price", typeof(Decimal));
        result1.Columns.Add("total", typeof(Decimal));

        foreach (var item in grp_q)
        {
            result1.Rows.Add(item.ID, item.name, item.product, item.price,item.total);
        }