从PropertyInfo创建表达式 [英] Create Expression from PropertyInfo

问题描述

我正在使用期望Expression<Func<T, object>>的API，并使用它在不同对象之间创建映射:

I'm using an API that expects an Expression<Func<T, object>>, and uses this to create mappings between different objects:

Map(x => x.Id).To("Id__c"); // The expression is "x => x.Id"

如何从PropertyInfo创建必要的表达式?这个想法是:

How can I create the necessary expression from a PropertyInfo? The idea being:

var properties = typeof(T).GetProperties();

foreach (var propInfo in properties)
{
    var exp = // How to create expression "x => x.Id" ???

    Map(exp).To(name);
}

推荐答案

您只需要Expression.Property，然后将其包装在lambda中即可.棘手的一点是，您也需要将结果转换为object:

You just need Expression.Property and then wrap it in a lambda. One tricky bit is that you need to convert the result to object, too:

var parameter = Expression.Parameter(x);
var property = Expression.Property(parameter, propInfo);
var conversion = Expression.Convert(property, typeof(object));
var lambda = Expression.Lambda<Func<T, object>>(conversion, parameter);
Map(lambda).To(name);

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