What's new in C# 10 version

Introduction

Subsequently your valuable go through our different articles like Open Souce Quartz job handler, MVC, 7 best Android cleaner apps and many more, it’s time to go through the latest version of C# 10 that is recently released by Microsoft. The most crucial thing is that C# 10 is supported on the .NET 6 application and it has added several improvements to the previous version for better utility.

The regular C# professionals can download the latest version of the .NET 6 SDK package from the .NET downloads page or Visual Studio 2022 to work with C# 10.

Table of Content

• Advanced Features of C# 10

  Record structs

  Improvements in structure types

  Interpolated string handler

  Constant interpolated strings

  Global using directives

  File-scoped namespace declaration

  Extended property patterns

  Record types can seal ToString

  Lambda expression enhancement

  Assignment and declaration in the same deconstruction

  Improved definite assignment

  Allow AsyncMethodBuilder attribute on methods

  CallerArgumentExpression attribute diagnostics

  Enhancement in #line pragma

  Warning wave 6

Advanced Features of C# 10

Following are the latest features of C# 10, incorporated by Microsoft to ease the advanced development task.

• Record structs

The main significant feature of this version of c# 10 is it has brought a big improvement in the structure of records through the use of the ‘record struct' or declaration of ‘read-only record struct'.

• Improvements in structure types

Here, a record is a reference type with the record class.

An instance parameterless constructor can be declared in a structure type and an instance field or property can be initiated properly at its declaration.

Also, keep in mind that a left-hand operand of the ‘with expression’ could be of any type of structure or any unspecified type of reference.

• Interpolated string handler

The interpolated string handler helps in making a type that assembles the resulting string from an interpolated string manifestation. This string handler converts an interpolated string into a string that can be used for argument purposes. The .NET core libraries get utilized this feature in various APIs.

• Constant interpolated strings

In C# 10, const strings may be initiated through string interpolation if all the placeholders are constant strings. In this advanced version of C#10, the String interpolation can build more readable constant strings as you create constant strings in your current application. Also, the placeholder expressions couldn't be numeric constants as those constants are changed to strings at run time. Probably, the current culture may put an impact on their string articulation.

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• Global using directives

In version c# 10, the global modifier with ‘using directive' notifies the compiler about the application of directive to all source files in the compilation. These are all source files in a specific project.

• File-scoped namespace declaration

In the c# 10, the developers would get a chance to use a new advanced aspect of the namespace declaration to get declared that all declarations that pursue are members of the same declared namespace:

namespace MyNamespace;

The above newly developed syntax ultimately saves space for namespace declarations both horizontally and vertically. Hence, the space issues for the developers will be resolved definitely.

• Extended property patterns

With C# 10, you can refer to the nested properties or fields within a specific property pattern.

For illustration, a pattern of the for

{ Prop1.Prop2: pattern }

is valid in version C# 10 and later versions.

Whereas, an equivalent pattern

{ Prop1: { Prop2: pattern } }

Is valid in version C# 8.0 and later versions.

• Record types can seal ToString

C# 10 includes the sealed modifier that can be added at the time of overriding ToStringin a record type. Sealing the ToString technique restricts the compiler from processing a ToString method for any obtained record types.
Mostly, a sealedToString makes sure all obtained records utilize the ToString method interpreted in a genuine base record category.

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• Lambda expression enhancement

C# 10 includes many enhancements in lambda expressions as follows.

1. Lambda expressions might possess a natural type, where the compiler could interpret a delegate type from the lambda expression or group of methods.
2. Also, Lambda expressions might declare a return type if the compiler is unable to interpret it.
3. In c# 10, Attributes apply to the lambda expressions.
   

The above features in C# 10 bring similarity of lambda expressions to usual methods and local functions. Also, these features make it easier to utilize lambda expressions without a declaration of a delegate type variable and work more efficiently with the new c# and ASP.Net Core Minimal APIs.

• Assignment and declaration in the same deconstruction

This update eliminates a constraint from previous versions of C#. In past, a deconstruction could assign all values to current variables, or initiate recently declared variables:

• Improved definite assignment

Before C# 10, there were several strategies where substantial assignment and null-state analysis generated warnings that were false positives. Usually, these involved comparisons to boolean values, calling a variable only in the true or false statements in an if statement, and null coalescing embodiments. These examples provoked warnings in previous versions of C#9.0, but not in C# 10:

The crucial impact of this advancement is that the warnings for a particular assignment and null-state calculation are more adequate.

• Allow AsyncMethodBuilder attribute on methods

In C# 10 and later versions of c#, you can mention various async method builders for a particular single method, to stipulate the method builder type for all types of methods that return a rendered task-like type. A customized async method builder facilitates progressive performance tuning strategies where a bestowed method may boost up from a custom builder.

• CallerArgumentExpression attribute diagnostics

In c#10, You can utilize ‘the system.Runtime.CompilerServices.CallerArgumentExpressionAttribute' to mention a parameter that the compiler replaces with another argument's text representation. Hence, the libraries can create more distinct diagnostics throughout this feature.

Example

The following c# code tests a distinct condition. If the condition becomes false, the exception message possesses the argument's text representation given to the condition:

• Enhancement in #line pragma

C# 10 aids a new type configuration for the #line pragma. You may not use the new format, but you'll see its valuable effects. This enhancement facilitates more fine-grained outcomes in domain-specific languages (DSL) in ASP.Net.

For example Razor. The Razor engine utilizes these improvements to enrich the debugging experience. Also, the debuggers can bring out your Razor source accurately.

• Warning wave 6

The warning wave 6 feature of c# 10 helps in the correction of inconsistencies between partial method CLR signatures. Now the compiler reports cs8826 when the signatures are syntactically different in C# 10.

Conclusion

In sum c# 10 has brought significant enhancement in c# development. Record struct is one of the major improvements that emphasize the c# programming experience.