C#的String.Create方法替换手机号或证件号为“*”

        /// <summary>
        /// 将传入的字符串中间部分字符替换成特殊字符
        /// </summary>
        /// <param name="value">需要替换的字符串</param>
        /// <param name="startLen">前保留长度</param>
        /// <param name="endLen">尾保留长度</param>
        /// <param name="specialChar">特殊字符</param>
        /// <returns>被特殊字符替换的字符串</returns>
        public static string ReplaceWithSpecialChar(this String value, int startLen, int endLen, string specialChar)
        {
            if (!value.IsNullOrEmpty())
            {
                value = string.Create(value.Length, (value, startLen, endLen, specialChar), (dst, v) =>
                {
                    ReadOnlySpan<char> startValue = v.value.Substring(0, v.startLen);
                    startValue.CopyTo(dst.Slice(0, startValue.Length));

                    int subLenth = v.value.Length - v.startLen - v.endLen;
                    subLenth = subLenth < 0 ? (v.value.Length - v.startLen) : subLenth;

                    ReadOnlySpan<char> specialValue = v.specialChar;
                    for (int i = 0; i < subLenth; i++)
                    {
                        specialValue.CopyTo(dst.Slice(startValue.Length + i, 1));
                    }

                    ReadOnlySpan<char> endValue = subLenth >= 0 ? v.value.Substring(v.startLen + subLenth) : string.Empty;

                    endValue.CopyTo(dst.Slice(startValue.Length + subLenth, endValue.Length));
                });
            }

            return value;
        }