NET Framework Validation Library

As I see it most applications have a requirement for some form of validation and a number of fantastic free offerings are available (I.E., Fluent Validation, Validation Block, Spring, Castle Windsor, etc). My question is why does the .NET Framework not include any inbuilt validation libraries?

I am aware the .NET Framework allows a developer the ability to build their own validation libraries/methods/etc. and anything provided as part of the .NET开发者_如何学JAVA Framework would not always meet everyone’s needs. But surely something could have been included?

ASP.NET has a minimal set of validators but these have not really been extended since .NET 2.0 was released.

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it does (sort of) - DataAnnotations

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The Microsoft Patterns and Pratices team has a Validation module in Enterprise Library. I've never used that module but the modules I have used in EntLib are very good.

I've had a bunch of discussions over the years with members of the P&P team and the sentiment is that there are somethings MS feel should (or should not) be part of the base framework. P&P sets the best practices on how to use certain MS technology and some of the results are considered for being rolled into the framework and others are better off in their own world.

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If Microsoft included something similar to one of those libraries;

1- everyone would hate it
2- would hinder innovation
3- everyone would hate it