如何从 C# ExpandoObject 按名称动态获取属性？
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How to dynamically get a property by name from a C# ExpandoObject?
提问by user2838966
I have an ExpandoObjectand want to make a getter for it that will return a property by name at runtime, where the name is specified in a string instead of hardcoded.
我有一个ExpandoObject并且想要为它制作一个 getter，它将在运行时按名称返回一个属性，其中名称在字符串中指定而不是硬编码。
For example, I CAN do this:
例如，我可以这样做：
account.features.isEmailEnabled;
and that will return true. accountis a ExpandoObject, and featuresis also an ExpandoObject. So I have an ExpandoObjectthat contains other ExpandoObjects.
这将返回true。 account是ExpandoObject，features也是ExpandoObject。所以我有一个ExpandoObject包含其他ExpandoObjects.
So what I want to be able to do is this:
所以我想要做的是：
account.features.GetProperty("isEmailEnabled");
and have that return true.
并让该返回为真。
The reason is that I have many features, and I want to be able to write one generic getter method where I can pass in the name of the feature I want, and the method will pass me back the value for account.features.whatever (where "whatever" is specified by passing in a string to the generic getter method). Otherwise I am going to have to write 30-some getters one for each feature.
原因是我有很多功能，我希望能够编写一个通用的getter方法，我可以在其中传入我想要的功能的名称，该方法会将 account.features.whatever 的值传回给我（其中“whatever”是通过将字符串传递给通用 getter 方法来指定的）。否则我将不得不为每个功能编写 30 个 getter。
I did a lot of research and tried doing something like:
我做了很多研究，并尝试做类似的事情：
var prop = account.features.GetType();
// this returns System.Dyanmic.ExpandoObject
followed by
其次是
var value = prop.GetProperty(featureNameAsString);
but valuealways comes back as null. I don't understand why. In the watch window I can do account.features.isEmailEnabledand it shows true and says its a boolean. But if I try to get at this value using the approach above and pass in isEmailEnabledas the featureNameAsStringI just get null.
但value总是返回空值。我不明白为什么。在监视窗口中，我可以做account.features.isEmailEnabled，它显示为 true 并表示它是一个布尔值。但是，如果我尝试使用上面的方法在这个值来获取和传递isEmailEnabled作为featureNameAsString我只是得到空。
Can someone please tell me what I may be doing wrong and what's a good approach, without it being too complex?
有人可以告诉我我可能做错了什么以及什么是好的方法，而不会太复杂？
I am working with ASP.NET under the 4.5.1 framework.
我在 4.5.1 框架下使用 ASP.NET。
采纳答案by Marc Gravell
ExpandoObjectprovides access both via dynamicand via IDictionary<string,object>- so you could just use the dictionary API:
ExpandoObject提供通过dynamic和通过访问IDictionary<string,object>- 所以你可以只使用字典 API：
var byName = (IDictionary<string,object>)account.features;
bool val = (bool)byName["isEmailEnabled"];
Or if the name is fixed, just:
或者，如果名称是固定的，只需：
bool val = ((dynamic)account).features.isEmailEnabled;
