using System;
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using System.Collections.Generic;
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using System.Linq.Expressions;
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namespace IStation.Untity
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{
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/// <summary>
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/// 使用表达式将一个对象映射为另一个对象（适用于大批量操作）
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/// </summary>
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/// <typeparam name="TIn"></typeparam>
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/// <typeparam name="TOut"></typeparam>
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public static class TransExp<TIn, TOut>
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{
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private static readonly Func<TIn, TOut> cache = GetFunc();
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private static Func<TIn, TOut> GetFunc()
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{
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ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "p");
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List<MemberBinding> memberBindingList = new List<MemberBinding>();
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foreach (var item in typeof(TOut).GetProperties())
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{
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if (!item.CanWrite)
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continue;
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MemberExpression property = Expression.Property(parameterExpression, typeof(TIn).GetProperty(item.Name));
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MemberBinding memberBinding = Expression.Bind(item, property);
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memberBindingList.Add(memberBinding);
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}
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MemberInitExpression memberInitExpression = Expression.MemberInit(Expression.New(typeof(TOut)), memberBindingList.ToArray());
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Expression<Func<TIn, TOut>> lambda = Expression.Lambda<Func<TIn, TOut>>(memberInitExpression, new ParameterExpression[] { parameterExpression });
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return lambda.Compile();
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}
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/// <summary>
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/// 转换
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/// </summary>
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/// <param name="tIn"></param>
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/// <returns></returns>
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public static TOut Translate(TIn tIn)
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{
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return cache(tIn);
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}
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}
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}
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