Is using reflection in .Net effects the performance reasonably bad? [duplicate]

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How costly is Reflection?

For sake of making my code generic I have started to use Reflection -to obtain some proerties in DTO objects and to set them-

Does usage of reflection to obtain properties and set them can effect the performance so badly compared to hard-coded setters?

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Yes, there is a cost involved in using Reflection.

However, the actual impact on the overall application performance varies. One rule of thumb is to never use Reflection in code that gets executed many times, such as loops. That will usually lead to algorithms that slow down exponentially (O(cⁿ)).

In many cases you can write generic code using delegates instead of Reflection, as described in this blog post.

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Yes, reflection is slow. You can try to decrease the impact of it by caching the xxxInfo (like MethodInfo, PropertyInfo etc) objects you retrieve via reflection per reflected Type and, i.e. keep them im a dictionary. Subsequent lookups in the dictionary are faster than retrieving the information every time.

You can also search here at SO for some questions about Reflection performance. For certain edge-cases there are pretty performant workarounds like using CreateDelegate to call methods instead of using MethodInfo.Invoke().

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Aside from the fact that it's slower having to set properties through reflection is a design issue as you apparently have separated concerns or encapsulated properties through object oriented design which is now preventing you from setting them directly. I would say you look at your design (there can be edge cases though) instead of thinking about reflection.

One of the downsides aside from the performance impact is that you're using a statically typed language thus the compiler checks your code and compiles it. Normally at compile time you have the certainty that all properties you're using are there and are spelled correctly. When you start to use reflection you push this check to runtime which is a real shame as you're (in my opinion) missing one of the biggest benefits of using a static typed language. This will also limit your refactoring opportunities in the (near) future as you're not sure anymore if you replaced all occurrences of an assignment for example when renaming a property.