using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var requestedPrivileges = "ClientId = 123456 And ClientId = 56789 AND (EmpUid = 12345978)";

        var sp = requestedPrivileges.Split(new string[] { "ClientId" }, StringSplitOptions.None);;

        var split = SplitString("ClientId", requestedPrivileges);

        foreach(var s in split)

        {

            Console.WriteLine(s);

        }

        Console.WriteLine(sp.Count());

        foreach(var s in sp)

        {

            Console.WriteLine("ClientId" + s);

        }

    }

    private static List<string> SplitString(string key, string stringToSplit)

        {

            List<string> splitString = new List<string>();

            var fromIndex = GetFirstIndex(key, stringToSplit);

            var toIndex = GetFirstIndex(key, stringToSplit.Substring(key.Length));

​

            if (toIndex == 0) // At the end of the string

            {

                splitString.Add(stringToSplit);

            }

            else if (fromIndex != 0) // Not at the end of the string and the start isn't at 0

            {

                splitString.Add(stringToSplit.Substring(0, fromIndex));

                splitString.AddRange(SplitString(key, stringToSplit.Substring(fromIndex)));

            }

            else

            {

                splitString.Add(stringToSplit.Substring(fromIndex, key.Length + toIndex));

                splitString.AddRange(SplitString(key, stringToSplit.Substring(fromIndex + key.Length + toIndex)));

            }

            return splitString;

        }

​

        private static int GetFirstIndex(string key, string stringToSplit)

        {

            int? minIndex = null;

            var index = stringToSplit.IndexOf(key);

            if ((index != -1 && minIndex == null) || (index != -1 && index < minIndex))

            {

                minIndex = index;

            }

            if (minIndex == null) minIndex = 0;

            return (int)minIndex;

        }

}