[C#] 확장 메소드

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
namespace ConsoleApp2
{
    public static class ExpandMethod
    {
        /// <summary>
        /// 문자열 변환
        /// </summary>
        /// <param name="obj">변환 하고자 하는 값</param>
        /// <param name="strDefault">기본값</param>
        /// <returns></returns>
        public static string ToStringEx(this object obj, string strDefault = "")
        {
            return Convert.ToString(obj).Trim() == string.Empty ? strDefault : Convert.ToString(obj).Trim();
        }
 
        /// <summary>
        /// 형변환 obj -> int
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static int ToIntEx(this object obj)
        {
            int rtn = 0;
 
            if (int.TryParse(Convert.ToString(obj), out rtn))
                return rtn;
            else
                return 0;
        }
 
        /// <summary>
        /// 형변환 obj -> double
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static double ToDoubleEx(this object obj)
        {
            double rtnDouble = 0;
 
            if (double.TryParse(Convert.ToString(obj), out rtnDouble))
                return rtnDouble;
            else
                return 0;
        }
    }
}