CODEWITHSUNDEEP
c#reflection
Sam
Sam

Reputation: 29009

Get PropertyInfo from property instead of name

Say, for example, I've got this simple class:

public class MyClass
{
  public String MyProperty { get; set; }
}

The way to get the PropertyInfo for MyProperty would be:

typeof(MyClass).GetProperty("MyProperty");

This sucks!

Why? Easy: it will break as soon as I change the Name of the Property, it needs a lot of dedicated tests to find every location where a property is used like this, refactoring and usage trees are unable to find these kinds of access.

Ain't there any way to properly access a property? Something, that is validated on compile time?
I'd love a command like this:

propertyof(MyClass.MyProperty);

Upvotes: 14

Views: 3440

Answers (3)

Profesor Caos
Profesor Caos

Reputation: 193

In the time since this question was posted, C# 6 has been released with the nameof operator. This allows a property to be accessed with the following 

PropertyInfo myPropertyInfo = typeof(MyClass).GetProperty(nameof(MyClass.MyProperty));

If you rename the property, this code will not compile (actually it will, since the rename will change this line of code as well if the rename is done properly).

Upvotes: 3

Jon Skeet
Jon Skeet

Reputation: 1503140

The closest you can come at the moment is to use an expression tree:

GetProperty<MyClass>(x => x.MyProperty)

and then suck the PropertyInfo out in GetProperty (which you'd have to write). However, that's somewhat brittle - there's no compile-time guarantee that the expression tree is only a property access.

Another alternative is to keep the property names that you're using somewhere that can be unit tested easily, and rely on that.

Basically what you want is the mythical infoof operator which has been talked about many times by the C# team - but which hasn't made the cut thus far :(

Upvotes: 6

Femaref
Femaref

Reputation: 61497

The whole point of reflection is to be able to access stuff at runtime. If we assume your operator would work, you already have the class information and thus the property, making the whole thing completely useless.

Upvotes: -2

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