[dragonwriter]

Partial classes and partial methods exist specifically to support having code that is automatically generated paired with a human-managed source file.

While you could use the support for them to split human-managed code across separate source files, that would be a horrible practice that I've never encountered in the wild, even in .NET shops with otherwise-atrocious practices and code quality.

[jasode]

>While you could use the support for them to split human-managed code across separate source files, that would be a horrible practice

To continue that type of advice, some say "#region/#endregion" is another language feature that's intended for code generators so that the IDE can collapse specific lines of code and hide it from view. Programmers should not be hand-coding "#region" themselves. That said, there is debate on that: https://softwareengineering.stackexchange.com/questions/5308...

[dragonwriter]

#region / #endregion, IME, largely serves to mitigate the visual offensiveness of poor (usually, completely neglected) design and (despite the potential utility in the case of code generation, and the utility it might have in the rare case where there is a good reason for a monster source file) I'd prefer it not to exist.

[partisan]

We use regions to standardize the layouts of our classes. Except for trivial classes, you will find the same regions in the same positions making it eas(ier) to find, for example, all methods implementing an interface, or all of the private helper methods.

[tigershark]

Regions are just useless visual clutter most of the time. You can put the methods/fields in the same order without using the regions. In my experience regions are a very bad practice used only to mask bad design that produced gigantic classes. The only place where I think they may be helpful is when you are writing a library and your class must be huge because you are implementing for example a Trie or some other collection or some other object pretty complicated that doesn't make sense to divide in smaller classes. And even in that case I would first try really really hard to split it in smaller entities rather than just having a thousands lines class with some regions around.

[partisan]

Not sure where to go from there. You've precluded the possibility that regions and good design should exist at the same time in the same file.

Where does the absolutism in the tech industry come from? We are a bunch of individuals who have individual experience and then try to form a view of the world that satisfies our experiences. What about the experiences you haven't had or conceived of? We are constantly rewriting the rules in our head to fit the new experiences we have every day to make sure we are right all of the time. Surely, our current world views are not complete or we would have no room to grow.

Still, I'll take your comment under advisement in case my classes are big, poorly designed non-Tries.

[DAllison]

Since it's buried at the bottom of the stackexchange: #region/endregion is useful for visually grouping Unit Tests per method under test. They're also occasionally useful to group interface implementations.

[taco_emoji]

You could just use nested classes for that, with the added benefit that the test framework will reflect that organization in its UX.

[DAllison]

The suggestion is appreciated. Thank you.

I have a minor doubt that I won't like the additional level of nesting incurred, but I'll attempt it regardless.

[noblethrasher]

Partial classes are also useful in the case that you want a nested class to have its own file.

[danbruc]

I think I may have manually created partial classes for huge classes to make them more manageable. Think for example expression tree visitors or collections of extension methods. Sure, I could just have created several classes like FooExtensions and BarExtension, but having a partial class Extensions seems ever so slightly better to me. But I generally agree, there are not many good use cases besides code generation and if you are tempted to do it, then you probably have a problem that has a different and better solution.