Indexof String By Byte[]

        /// <summary>在字节数组里搜索字符串key第一次出现的位置
        /// </summary>
        /// <param name="b1">字节数组</param>
        /// <param name="key">字符串</param>
        /// <returns>搜索为空返回-1</returns>
        public static int BytesIndexOf(byte[] b1, string key)
        {
            byte[] keyByte = System.Text.Encoding.Default.GetBytes(key);

            for (int i = 0; i < b1.Length; i++)
            {
                if (b1[i] == keyByte[0] && i + keyByte.Length < b1.Length)
                {
                    bool tag = true;
                    for (int find = 1; find < keyByte.Length - 1; find++)
                        if (b1[i + find] != keyByte[find]) tag = false;
                    if (tag) return i;
                }
            }
            return -1;
        }

        /// <summary>在字节数组里从指定位置开始搜索字符串key第一次出现的位置

        /// </summary>
        /// <param name="b1">字节数组</param>

        /// <param name="start">开始搜索位置</param>

        /// <param name="key">字符串</param>

        /// <returns>搜索为空返回-1</returns>
        public static int BytesIndexOf(byte[] b1, int start, string key)
        {
            byte[] keyByte = System.Text.Encoding.Default.GetBytes(key);

            for (int i = start; i < b1.Length; i++)
            {
                if (b1[i] == keyByte[0] && i + keyByte.Length < b1.Length)
                {
                    bool tag = true;
                    for (int find = 1; find < keyByte.Length - 1; find++)
                        if (b1[i + find] != keyByte[find]) tag = false;
                    if (tag) return i;
                }
            }
            return -1;
        }