C# 表达式目录树的应用详解

下面小编就为大家分享一篇C# 表达式目录树的应用详解，具有很好的参考价值，希望对大家有所帮助。一起跟随小编过来看看吧

使用表达式目录树实现两个不同类型的属性赋值：

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									public class People

									{

									public int Age { get; set; }

									public string Name { get; set; }

									public int Id;

									}

									public class PeopleCopy

									{

									public int Age { get; set; }

									public string Name { get; set; }

									public int Id;

									}

									public class Class1

									{

									private static Dictionary<string, object> _Dic = new Dictionary<string, object>();

									private static TOut TransExp<TIn, TOut>(TIn tIn) {

									string key = $"funckey_{typeof(TIn).FullName}_{typeof(TOut).FullName}";

									if (!_Dic.Keys.Contains(key)) { 

									ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "p");

									List<MemberBinding> memberBindingList = new List<MemberBinding>();

									foreach (var item in typeof(TOut).GetProperties())

									{

									PropertyInfo propertyInfo = typeof(TIn).GetProperty(item.Name);

									if (propertyInfo == null) { continue; }

									MemberExpression property = Expression.Property(parameterExpression, propertyInfo);

									memberBindingList.Add(Expression.Bind(item, property));

									}

									foreach (var item in typeof(TOut).GetFields())

									{

									FieldInfo fieldInfo = typeof(TIn).GetField(item.Name);

									if (fieldInfo == null) { continue; }

									MemberExpression property = Expression.Field(parameterExpression, fieldInfo);

									memberBindingList.Add(Expression.Bind(item, property));

									}

									Expression<Func<TIn, TOut>> expression = Expression.Lambda<Func<TIn, TOut>>(Expression.MemberInit(Expression.New(typeof(TOut)), memberBindingList), new ParameterExpression[]

									{

									parameterExpression

									});

									Func<TIn, TOut> func = expression.Compile();

									_Dic.Add(key,func);

									}

									return ((Func < TIn, TOut > )_Dic[key])(tIn);

									}

									}

									static void Main(string[] args)

									{

									List<ClassLibrary1.PeopleCopy> PeoleCopyList = new List<ClassLibrary1.PeopleCopy>();

									for (int i = 0; i < 5; i++)

									{

									ClassLibrary1.People people = new ClassLibrary1.People() { Id = 5+1, Age = 25, Name = "aaa"+i };

									PeoleCopyList.Add(Class1.ToutGet<ClassLibrary1.People, ClassLibrary1.PeopleCopy>(people));

									}

									}