using System;

using System.Data;

​

public class Program

{

    public void Main()

    {

        DataTable dt = new DataTable();

        dt.Columns.Add("test", typeof(string));

        dt.Columns.Add("tset", typeof(string));

        dt.Columns.Add("demo", typeof(string));

        dt.Columns.Add("omed", typeof(int));

        DataTable returnedDT = WorkWithDT(dt);

        foreach (DataRow row in dt.Rows){

        Console.WriteLine("$$$ Row $$$");

        Console.WriteLine("test: " + row["test"] + "- tset: " + row["tset"] + "- demo: " + row["demo"] + "- omed: " + row["omed"]);

        Console.ReadLine();

        }

    }

    public DataTable WorkWithDT(DataTable tempTable){

        DataRow newTempRow = tempTable.NewRow();

         newTempRow["test"] = "hello";

        tempTable.Rows.Add(newTempRow);

        return tempTable;

    }

}