Question

I generally live by the rule that Global variables / functions are evil and that every piece of code should live in the class to which it pertains.

This is a very easy rule to follow, and I believe that I haven't ever run into an issue with this rule until now.

Today, however, I need to add a function to my assembly rather than to a specific class. That is, almost all of my classes could have a use for this particular function.

Where should I put this function (+1 overload)?

If I put it in a "Utilities" class, I feel dirty. If I tack it on to a semi-related class, and let other classes call it directly, I feel worse.

This particular piece of code basically chops a IList<PointF> into a normalized list. I feel right now that adding it as an extension method on IList<PointF> may be the best bet...

Was it helpful?

Solution

If this is an operation on an IList<PointF>, then it should be an extension method on IList<PointF>.

Generally, Utils and Helper type classes should be avoided. More often than not, you will find that what you may think is a utility method, is actually a rather specific method that probably belongs in a class of its own (just like you say). However, there will be domain specific cases where Util-like classes (classes which group related useful methods) are valid entities.

OTHER TIPS

There is nothing wrong with "global" variables and methods. You use them all the time. The framework likes to call them "static" classes or "static" methods.

I rarely need to, but I usually add an internal static class Util in the namespace that the method/variable is needed for C# and a module for VB.NET.

Samples from .NET Framework

  • System.Collections.Specialized.CollectionsUtil
  • System.Net.WebUtility
  • Check Microsoft's source code for .NET Framework. You will find numerous internal utility classes.

You should put it into a 'ListUtilities' or PointListUtilities class, of course. Then you aren't breaking the single responsibility principle, which is the primary problem with a catch-all 'Utilities' class.

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