c#字符类型判断

       /// <summary>
        /// 判断是否为空字符串
        /// </summary>
        /// <param name="p_Source">需要判断的字符串</param> 
        /// <remarks>全为空格的字符串(包括全角空格和半角)或字符串为 null 返回 true，否则返回false</remarks>
        /// <returns>true: 空字符串, false 非空字符串
        /// </returns>
        /// <seealso cref="IsNotNullString"/>
        public static bool IsNullString(string p_Source)
        {
            if (p_Source == null)
            {
                return true;
            }
            p_Source = p_Source.Trim(' ', '　');
            if (p_Source == String.Empty)
            {
                return true;
            }
            return false;
        }

        /// <summary>
        /// 判断是否不为空字符串
        /// </summary>
        /// <param name="p_Source">需要判断的字符串</param> 
        /// <returns></returns>
        public static bool IsNotNullString(string p_Source)
        {
            return !IsNullString(p_Source);
        }

        /// <summary>
        /// 判断是否为空
        /// </summary>
        /// <param name="str">待检查数据。""，&nbsp;，null，&nbsp，undefined，Length == 0</param>
        /// <returns></returns>
        public static bool IsEmpty(string str)
        {
            if (string.IsNullOrEmpty(str) || str == "&nbsp;" || str == "&nbsp" || str.Length == 0 || str == "undefined") return true;

            return false;
        }

        /// <summary>
        /// 判断输入是否为日期类型
        /// </summary>
        /// <param name="strSrc">待检查数据 </param>
        /// <returns></returns>
        public static bool IsDate(string strSrc)
        {
            try
            {
                DateTime d = DateTime.Parse(strSrc);
                return true;
            }
            catch
            {
                return false;
            }
        }

        /// <summary>
        /// 判断是否为数字
        /// </summary>
        /// <param name="strSrc">待检查数据</param>
        /// <returns></returns>
        public static bool IsNumeric(string strSrc)
        {
            if (strSrc != null && Regex.IsMatch(strSrc, @"^\d+$")) return true;
            return false;
        }

        /// <summary>
        /// 将字符串转换成 html 编码字符
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string HtmllEncode(string str)
        {
            return System.Web.HttpUtility.HtmlEncode(str);
        }

        /// <summary>
        /// 将 html 解码
        /// </summary> 
        /// <param name="str">要转换的字符串</param>
        /// <returns></returns>
        public static string HtmlDecode(string str)
        {
            return System.Web.HttpUtility.HtmlDecode(str);
        }