Quasar/Client/Core/Helper/FileHelper.cs

using System;
using System.Text;

namespace xClient.Core.Helper
{
    public static class FileHelper
    {
        private const string CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        private static readonly Random _rnd = new Random(Environment.TickCount);

        public static string GetRandomFilename(int length, string extension = "")
        {
            StringBuilder randomName = new StringBuilder(length);
            for (int i = 0; i < length; i++)
                randomName.Append(CHARS[_rnd.Next(CHARS.Length)]);

            return string.Concat(randomName.ToString(), extension);
        }
    }
}