是否有可能创建一个基于字符串值，表示其类型的对象实例？ [英] Is it possible to create an object instance based on a string value denoting its type?

问题描述

我试图动态地创建某种类型的基础上我的XML文档中的字符串中的LINQ到XML查询的对象。我已经习惯了能够动态地创建任何类型的PHP和JavaScript的对象，只需能写的东西，如：

I'm trying to dynamically create an object of a certain type in a LINQ-to-XML query based on a string within my XML document. I'm used to being able to dynamically create an object of any type in PHP and JavaScript by simply being able to write something like:

$obj = new $typeName();

在理想情况下，我希望能够做这样的事情：

Ideally, I'd like to be able to do something like:

List<someObj> = (from someObjs in XMLfile
                 select new someObj()
                 {
                     Name = (string)someObjs.Element("name"),
                     NestedObj = new someObjs.Element("nestedObj").Element("type")()
                     {
                         NestedName = (string)someObjs.Element("nestedObj").Element("name")
                     }
                 }).ToList();

我只是不知道如何做没有抓住当前执行的程序集的保持。

I just can't figure out how to do it without grabbing a hold of the current executing assembly.

推荐答案

您可以使用：

Activator.CreateInstance(Type.GetType(typeName))

当然，这只是作品类型的参数的构造函数。

Of course, this only works for types with a parameterless constructor.

更新（初始化对象）：

您可以使用C＃4动态类型的功能来设置新创建的对象的属性：

You can use C# 4 dynamic typing features to set properties of the newly created object:

dynamic newObj = Activator.CreateInstance(Type.GetType(typeName));
newObj.NestedName = str;

在一个LINQ到XML查询的背景下，你可能不得不求助于有明确的身体lambda语法

In the context of a LINQ to XML query, you may have to resort to lambda syntax with explicit body:

var list = XMLFile.Select(someObjs => {
    dynamic nestedObj = Activator.CreateInstance(
       Type.GetType(someObjs.Element("nestedObj").Element("type")));
    nestedObj.NestedName = (string)someObjs.Element("nestedObj").Element("name");
    return new someObj {
        Name = (string)someObjs.Element("name"),
        NestedObj = nestedObj
    };
}).ToList();

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