using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace Infrastructure.Extensions
{
    public static class StringExtension
    {

        /// <summary>
        /// SQL条件拼接
        /// </summary>
        /// <param name="str"></param>
        /// <param name="condition"></param>
        /// <returns></returns>
        public static string If(this string str, bool condition)
        {
            return condition ? str : string.Empty;
        }
        /// <summary>
        /// 判断是否为空
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static bool IfNotEmpty(this string str)
        {
            return !string.IsNullOrEmpty(str);
        }

        /// <summary>
        /// 注意：如果替换的旧值中有特殊符号，替换将会失败，解决办法 例如特殊符号是“(”：  要在调用本方法前加oldValue=oldValue.Replace("(","//(");
        /// </summary>
        /// <param name="input"></param>
        /// <param name="oldValue"></param>
        /// <param name="newValue"></param>
        /// <returns></returns>
        public static string ReplaceFirst(this string input, string oldValue, string newValue)
        {
            Regex regEx = new Regex(oldValue, RegexOptions.Multiline);
            return regEx.Replace(input, newValue == null ? "" : newValue, 1);

        }
    }
}