using System;

public class Program

{

    public static void Main()

    {

        decimal someDecimal = 356342.14M;

        //Casting way

        string someString = ((int)someDecimal).ToString();              

        Console.WriteLine(someString);

        //Extension method casting way

        Console.WriteLine(someDecimal.ToIntString());

        //By far the best way

        Console.WriteLine(someDecimal.ToString("F0", System.Globalization.CultureInfo.InvariantCulture));

    }   

}

​

public static class DecimalExtensions

{

    public static string ToIntString(this decimal input)

    {

        return ((int)input).ToString();

    }

}