Co do pierwszego pytania, dot. stringa to zrobiłem Ci rozszerzenie dla Stringa, czyli wklejanie drugiego stringa w określony index:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
public static class StringExtensions
{
/// <summary>
///
/// </summary>
/// <param name="str"></param>
/// <param name="second">blah</param>
/// <param name="index">IF -1 adds second string at end</param>
/// <returns></returns>
public static string JoinOnPosition(this string str, string second, int index = -1)
{
if (index == -1)
return str + second;
return str.Substring(0, index) + second + str.Substring(index);
}
}
class Program
{
static void Main(string[] args)
{
string jeden = "Kofel ssie";
string dwa = " nie";
Console.WriteLine( jeden );
Console.WriteLine( jeden.JoinOnPosition(dwa,5) );
Console.ReadKey();
}
}
}