如何当你有这个名字在另一个变量设置C＃4动态对象的属性 [英] How to set a property of a C# 4 dynamic object when you have the name in another variable

问题描述

我在寻找一种方式来修改一个动态仅在运行时称为属性的名称C＃4.0对象的属性。

I'm looking for a way to modify properties on a dynamic C# 4.0 object with the name of the property known only at runtime.

有没有办法做这样的事情（ ExpandoObject 只是用来作为一个例子，这可能是任何类实现 IDynamicMetaObjectProvider ）：

Is there a way to do something like (ExpandoObject is just used as an example, this could be any class that implements IDynamicMetaObjectProvider):

string key = "TestKey";
dynamic e = new ExpandoObject();
e[key] = "value";

这将等同于：

Which would be equivalent to:

dynamic e = new ExpandoObject();
e.TestKey = "value";

或者是唯一的出路思考？

Or is the only way forward reflection?

推荐答案

不是很容易，没有。反思是不行的，因为它假设一个普通类型的模型，这是的没有的全方位动力。如果你实际上只是说话有规则物体，那么就使用反射在这里。否则，我希望你可能要反向工程，code编译器会发出一个基本的分配和调整它有一个灵活的成员名称。我会说实话，虽然：这不是一个有吸引力的选择;一个简单的：

Not very easily, no. Reflection doesn't work, since it assumes a regular type model, which is not the full range of dynamic. If you are actually just talking to regular objects, then just use reflection here. Otherwise, I expect you may want to reverse-engineer the code that the compiler emits for a basic assignment, and tweak it to have a flexibly member-name. I'll be honest, though: this isn't an attractive option; a simple:

dynamic foo = ...
foo.Bar = "abc";

语句：

if (<Main>o__SiteContainer0.<>p__Site1 == null)
{
    <Main>o__SiteContainer0.<>p__Site1 = CallSite<Func<CallSite, object, string, object>>.Create(Binder.SetMember(CSharpBinderFlags.None, "Bar", typeof(Program), new CSharpArgumentInfo[] { CSharpArgumentInfo.Create(CSharpArgumentInfoFlags.None, null), CSharpArgumentInfo.Create(CSharpArgumentInfoFlags.Constant | CSharpArgumentInfoFlags.UseCompileTimeType, null) }));
}
<Main>o__SiteContainer0.<>p__Site1.Target(<Main>o__SiteContainer0.<>p__Site1, foo, "abc");

---

如果你想要一个，工程动态和非动态对象的方法： FastMember 是得心应手了这一点，工作在任一类型或对象级别：

---

If you want an approach that works for both dynamic and non-dynamic objects: FastMember is handy for this, and works at either the type or object level:

// could be static or DLR 
var wrapped = ObjectAccessor.Create(obj); 
string propName = // something known only at runtime 
Console.WriteLine(wrapped[propName]);

提供的NuGet，以及大量的动态和非动态的场景进行了优化。

available on Nuget, and heavily optimised for both dynamic and non-dynamic scenarios.

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