// Int32 num1 = 4; //long num1 = 4; Int64 num1 = 4; num1 = num1 << 1;//右移动 byte[] bs = BitConverter.GetBytes(num1); BitArray arr = new BitArray(bs); //设置第四位为打开状态 //arr[4] = true; var sb = new StringBuilder(); for (int i = arr.Length-1; i >=0; i--) { if (arr[i] == true ) { sb.Append("1"); } else { sb.Append("0"); } } Console.WriteLine(string.Format("Length is :{0}",arr.Length)); Console.WriteLine(sb.ToString()); Console.WriteLine(Convert.ToInt64(sb.ToString(),2)); Console.ReadKey();