.NET Standard: What it is and how to use

What really is dot net standard?  

Let me try to put it in simple words. We used to use different BCL's for different frameworks and remembering it is a tough job. So Microsoft once again has come up with a solution to help developers to put a little less load on on the brain to remember the API's. They have replaced all the BCL's with a common one which they are calling as .net Standard. 

.Net Standard 2.0 has around 32,000 API's. You can download the list from here or you can check it here at GitHub.

.Net Standard replaces Portable Class Libraries (PCLs) as the tool for building .NET libraries that work everywhere 

How to use it? 

If you have .net core installed on your machine you can start working on .net Standard just by creating a Class Library. Yes, the old Class library is now Class Library for .net standard. 

For those who understand pictures better or would like to read less. 

Above pictures are taken from a slide of Immo Landwerth. 

The table below can be used as the reference for writing a class library using the standard.

If you are choosing a version for writing .net standard, you should consider a trade-off which is the 

higher the version of .net standard more apis are available. Lower the version, more platforms have already implemented it.

You can follow .net standard on GitHub 

Below are the list of API's added newly in .net standard 2.0

Namespace	#APIs
Microsoft.Win32.SafeHandles	22
System	1,366
System.CodeDom.Compiler	46
System.Collections	335
System.Collections.Generic	23
System.Collections.ObjectModel	1
System.Collections.Specialized	281
System.ComponentModel	1,843
System.ComponentModel.Design	565
System.ComponentModel.Design.Serialization	155
System.Configuration.Assemblies	13
System.Data	1,587
System.Data.Common	907
System.Data.SqlTypes	971
System.Diagnostics	826
System.Diagnostics.CodeAnalysis	2
System.Diagnostics.Contracts	89
System.Diagnostics.SymbolStore	146
System.Diagnostics.Tracing	2
System.Drawing	520
System.Dynamic	226
System.Globalization	217
System.IO	309
System.IO.Compression	8
System.IO.IsolatedStorage	134
System.IO.MemoryMappedFiles	66
System.IO.Pipes	125
System.Linq	366
System.Linq.Expressions	50
System.Net	1,360
System.Net.Cache	52
System.Net.Http.Headers	20
System.Net.Mail	289
System.Net.Mime	75
System.Net.NetworkInformation	696
System.Net.Security	194
System.Net.Sockets	168
System.Net.WebSockets	188
System.Numerics	1
System.Reflection	403
System.Reflection.Emit	3
System.Resources	91
System.Runtime	12
System.Runtime.CompilerServices	190
System.Runtime.ConstrainedExecution	22
System.Runtime.ExceptionServices	6
System.Runtime.InteropServices	106
System.Runtime.InteropServices.ComTypes	15
System.Runtime.Serialization	486
System.Runtime.Serialization.Formatters	13
System.Runtime.Serialization.Formatters.Binary	23
System.Runtime.Serialization.Json	80
System.Runtime.Versioning	33
System.Security	124
System.Security.Authentication	11
System.Security.Authentication.ExtendedProtection	36
System.Security.Claims	206
System.Security.Cryptography	575
System.Security.Cryptography.X509Certificates	76
System.Security.Permissions	88
System.Security.Principal	41
System.Text	83
System.Text.RegularExpressions	31
System.Threading	330
System.Threading.Tasks	66
System.Timers	39
System.Transactions	223
System.Web	32
System.Xml	1,362
System.Xml.Linq	7
System.Xml.Resolvers	25
System.Xml.Schema	967
System.Xml.Serialization	943
System.Xml.XPath	261
System.Xml.Xsl	140