Member Avatar for serkan sendur

I dont clean the unnecessary namespaces that .net automatically generates. Is there any problem with that?

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  • Latest Post Latest Post by SheSaidImaPregy

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Short answer: no runtime cost. As noted, an unused using (for example using System.IO;) only affects name lookup at compile time — it does not make the CLR load assemblies or add runtime overhead. For the formal definition see the C# using directive documentation: Using directive (C#).

Why that matters: a using simply tells the compiler where to look when you refer to an unqualified type name. It does not add assembly references (those come from your project file) and it does not instantiate or load types by itself. The main practical effects are compile-time/IDE related: a lot of unused imports can slightly slow Intellisense or compilation in very large projects, and they can cause ambiguity if multiple namespaces define the same short type name.

Practical guidance:

  • Keep source files tidy for readability and to avoid accidental ambiguous-type errors.
  • Use your IDE’s cleanup features (Remove/Sort Usings, Code Cleanup) or analyzers to remove unused directives automatically.
  • In modern .NET (SDK-style/.NET 6+) consider implicit or explicit global using to reduce per-file clutter; these still have no runtime cost (Implicit using directives).
  • If you need deeper background on namespaces, Microsoft’s namespaces guide is useful: Namespaces (C#).

Bottom line for : leaving a few extra using lines won’t hurt performance, but removing them (or using automated cleanup) improves clarity and avoids potential name conflicts.

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Member Avatar for SheSaidImaPregy

No, there are no performance hits, no overhead, or anything UNLESS you actually use the namespace.

So having System.IO and not using any reference to it does nothing towards your application. It just allows the application to use the namespace, if it is needed.

Member Avatar for serkan sendur

What is your reference SheSaid ? :). Do you have any resources about it? Article or so?

Member Avatar for SheSaidImaPregy

I've looked it up before when I started with VS because it imported more than 20 that I don't use. Let me find it.

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