Example:
DataTable dt = new DataTable("table");
dt.Columns.Add("id", Type.GetType("System.Int32"));
dt.Columns.Add("name", Type.GetType("System.String"));
DataRow dr = dt.NewRow();
dr["id"] = 1;
dr["name"] = "john";
dt.Rows.Add(dr);
dr = dt.NewRow();
dr["id"] = 2;
dr["name"] = "dan";
dt.Rows.Add(dr);
DataTable tbl = (from DataRow dr1 in dt.Rows
where dr1["id"].ToString() == "1"
select dr).CopyToDataTable();