Things in .NET Framework 4 that every programmer should know [closed]

Answer 1

System.Numerics.BigInteger - Represents an arbitrarily large signed integer.

System.Numerics.Complex - Represents a complex number.

Answer 2

For the sake of readability, I'll add my discovery as written in the question it self.

When using AJAX, you can specify EnableCdn property for the scriptManager to load values from CDNs (such as Microsoft CDN)

Answer 3

Optional parameters is one of my favorites. The dynamic type seems to be promising

Answer 4

The way how C# implements event fields is new. It no longer internally does a very bad lock (this) by default. Events are still thread-safe however because an Interlocked.CompareExchange(...) mechanism is now used instead.

This lead to some changes that could be breaking in some edge cases. More info:

• Chris Burrows' Blog: Events get a little overhaul in C# 4, part I: Locks
• Chris Burrows' Blog: Events get a little overhaul in C# 4, part II: Semantic Changes and +=/-=
• Channel 9: Whirlwind 14: What's new in C# 4 - Events

Answer 5

Awesome thing, Client IDs can be manipulated:

http://weblogs.asp.net/scottgu/archive/2010/03/30/cleaner-html-markup-with-asp-net-4-web-forms-client-ids-vs-2010-and-net-4-0-series.aspx

No more CTL0001$_DIV0003_TextBox1001$ or whatever...

Answer 6

You can use memory-mapped files (in the same way that native Windows functions access memory-mapped files) to edit very large files and to create shared memory for interprocess communication. For a detailed explication see: http://msdn.microsoft.com/en-us/library/dd997372.aspx