private static Dictionary<string, object> _Dic = new Dictionary<string, object>(); private static TOut TransExp<TIn, TOut>(TIn tIn) { string key = string.Format("trans_exp_{0}_{1}", typeof(TIn).FullName, typeof(TOut).FullName); if (!_Dic.ContainsKey(key)) { ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "p"); List<MemberBinding> memberBindingList = new List<MemberBinding>(); foreach (var item in typeof(TOut).GetProperties()) { if (!item.CanWrite) continue; MemberExpression property = Expression.Property(parameterExpression, typeof(TIn).GetProperty(item.Name)); MemberBinding memberBinding = Expression.Bind(item, property); memberBindingList.Add(memberBinding); } MemberInitExpression memberInitExpression = Expression.MemberInit(Expression.New(typeof(TOut)), memberBindingList.ToArray()); Expression<Func<TIn, TOut>> lambda = Expression.Lambda<Func<TIn, TOut>>(memberInitExpression, new ParameterExpression[] { parameterExpression }); Func<TIn, TOut> func = lambda.Compile(); _Dic[key] = func; } return ((Func<TIn, TOut>)_Dic[key])(tIn); }
操作泛型
public static class TransExpV2<TIn, TOut> { private static readonly Func<TIn, TOut> cache = GetFunc(); private static Func<TIn, TOut> GetFunc() { ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "p"); List<MemberBinding> memberBindingList = new List<MemberBinding>(); foreach (var item in typeof(TOut).GetProperties()) { if (!item.CanWrite) continue; MemberExpression property = Expression.Property(parameterExpression, typeof(TIn).GetProperty(item.Name)); MemberBinding memberBinding = Expression.Bind(item, property); memberBindingList.Add(memberBinding); } MemberInitExpression memberInitExpression = Expression.MemberInit(Expression.New(typeof(TOut)), memberBindingList.ToArray()); Expression<Func<TIn, TOut>> lambda = Expression.Lambda<Func<TIn, TOut>>(memberInitExpression, new ParameterExpression[] { parameterExpression }); return lambda.Compile(); } public static TOut Trans(TIn tIn) { return cache(tIn); } }
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原文地点：https://www.cnblogs.com/zhesong/p/CSBDSS.html
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