Question

I know that Reflection can be expensive. I have a class that gets/sets to properties often, and one way I figured was to cache the reflection somehow. I’m not sure if I’m supposed to cache an expression or what to do here really. This is what I’m currently doing:

typeof(T).GetProperty(propName).SetValue(obj, value, null);
typeof(T).GetProperty(propName).GetValue(obj, null);

So… what would be the best way to make this quicker?

Answer 1

You should cache results of

typeof(T).GetProperty(propName); 

and

typeof(T).GetProperty(propName);

Another possible approach is to combine PropertyInfo.GetGetMethod Method (or PropertyInfo.GetSetMethod Method for setter) with Delegate.CreateDelegate Method and invoke the resulting delegate every time you need to get/set values. If you need this to work with generics you can use approach from this question: CreateDelegate with unknown types

This should be much faster compared to reflection:
Making reflection fly and exploring delegates

There are also other ways to get/set values in a faster way. You can use expression trees or DynamicMethod to generate the il at runtime. Have a look at these links:

Late-Bound Invocations with DynamicMethod

Delegate.CreateDelegate vs DynamicMethod vs Expression