using System;

    using System.Linq;

    public class Program

    {

        static readonly Random _random = new System.Random(Environment.TickCount);

        const string dictionary = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklpmnopqrstuvwxyz0123456789!@#$%^&*()_+-=";

        static string GetPassword(int length)

        {

            return new String

                (

                    dictionary

                       .OrderBy( a => _random.NextDouble() )

                       .Take(length)

                       .ToArray()

                );

        }

​

        static string GetPassword(int length, int maxRepeats)

        {

            return new String

                (

                    Enumerable.Range(0, maxRepeats)

                       .SelectMany( i => dictionary)

                       .OrderBy( a => _random.NextDouble() )

                       .Take(length)

                       .ToArray()

                );

        }

​

        public static void Main()

        {

            var s = GetPassword(30);

            Console.WriteLine(s);

        }

    }