using System;

using System.Web;

​

public class Program

{

    public static void Main()

    {

        var components = "SOME_ORIGINAL_FIELD_NAME".Split("_");

        var format1 = "{0}{1}_{2}_{3}";

        var format2 = "{0}_{1}{2}{3}";

​

        var strFormat1 = String.Format(format1, components); // SOMEORIGINAL_FIELD_NAME

        var strFormat2 = String.Format(format2, components); // SOME_ORIGINALFIELDNAME

        Console.WriteLine(strFormat1);

        Console.WriteLine(strFormat2);

    }

}