[C#/LINQ] Expression 클래스 : 지정 타입으로 변환하기

TestProject.zip

0.00MB

▶ TypeHelper.cs

using System;
using System.Collections.Generic;
using System.Linq.Expressions;

namespace TestProject
{
    /// <summary>
    /// 타입 헬퍼
    /// </summary>
    public static class TypeHelper
    {
        //////////////////////////////////////////////////////////////////////////////////////////////////// Field
        ////////////////////////////////////////////////////////////////////////////////////////// Static
        //////////////////////////////////////////////////////////////////////////////// Private

        #region Field

        /// <summary>
        /// 캐스트 캐시 딕셔너리
        /// </summary>
        private static readonly Dictionary<Tuple<Type, Type>, Func<object, object>> _castCacheDictionary = new Dictionary<Tuple<Type, Type>, Func<object, object>>();

        #endregion

        //////////////////////////////////////////////////////////////////////////////////////////////////// Method
        ////////////////////////////////////////////////////////////////////////////////////////// Static
        //////////////////////////////////////////////////////////////////////////////// Public

        #region 타입 변경하기 - ChangeType(sourceObject)

        /// <summary>
        /// 타입 변경하기
        /// </summary>
        /// <typeparam name="TTarget">타겟 타입</typeparam>
        /// <param name="sourceObject">소스 객체</param>
        /// <returns>타입 변경 객체</returns>
        public static TTarget ChangeType<TTarget>(object sourceObject)
        {
            return (TTarget)GetCastFunction(sourceObject.GetType(), typeof(TTarget)).Invoke(sourceObject);
        }

        #endregion

        //////////////////////////////////////////////////////////////////////////////// Private

        #region 캐스트 함수 생성하기 - CreateCastFunction(sourceType, targetType)

        /// <summary>
        /// 캐스트 함수 생성하기
        /// </summary>
        /// <param name="sourceType">소스 타입</param>
        /// <param name="targetType">타겟 타입</param>
        /// <returns>캐스트 함수</returns>
        private static Func<object, object> CreateCastFunction(Type sourceType, Type targetType)
        {
            ParameterExpression parameterExpression = Expression.Parameter(typeof(object));

            return Expression.Lambda<Func<object, object>>
            (
                Expression.Convert
                (
                    Expression.ConvertChecked(Expression.Convert(parameterExpression, sourceType), targetType),
                    typeof(object)
                ),
                parameterExpression
            ).Compile();
        }

        #endregion
        #region 캐스트 함수 구하기 - GetCastFunction(sourceType, targetType)

        /// <summary>
        /// 캐스트 함수 구하기
        /// </summary>
        /// <param name="sourceType">소스 타겟</param>
        /// <param name="targetType">타겟 타입</param>
        /// <returns>캐스트 함수</returns>
        private static Func<object, object> GetCastFunction(Type sourceType, Type targetType)
        {
            lock(_castCacheDictionary)
            {
                Tuple<Type, Type> keyTuple = new Tuple<Type, Type>(sourceType, targetType);

                Func<object, object> castFunction;

                if(!_castCacheDictionary.TryGetValue(keyTuple, out castFunction))
                {
                    castFunction = CreateCastFunction(sourceType, targetType);

                    _castCacheDictionary.Add(keyTuple, castFunction);
                }

                return castFunction;
            }
        }

        #endregion
    }
}

 

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▶ Program.cs

using System;

namespace TestProject
{
    /// <summary>
    /// 프로그램
    /// </summary>
    class Program
    {
        //////////////////////////////////////////////////////////////////////////////////////////////////// Method
        ////////////////////////////////////////////////////////////////////////////////////////// Static
        //////////////////////////////////////////////////////////////////////////////// Private

        #region 프로그램 시작하기 - Main()

        /// <summary>
        /// 프로그램 시작하기
        /// </summary>
        private static void Main()
        {
            double sourceValue = 100d;

            int targetValue = TypeHelper.ChangeType<int>(sourceValue);

            Console.WriteLine($"소스 값 : {sourceValue.GetType()}, {sourceValue}");
            Console.WriteLine($"타겟 값 : {targetValue.GetType()}, {targetValue}");
        }

        #endregion
    }
}