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111 lines
3.5 KiB
Markdown
111 lines
3.5 KiB
Markdown
**Previews**
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Preliminary drafts of C# 11 and .NET 7 - Modern Cross-Platform Development were written and tested with .NET 7 Preview 1. Microsoft will release monthly previews until August, then two release candidates in September and October, before the general availablility (GA) release in November 2022. Each month I will add new content to this page that will then be added to the final drafts in September.
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- [New content for .NET 7 Preview 2](#new-content-for-net-7-preview-2)
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- [Chapter 1](#chapter-1)
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- [Command Line Interface commands](#command-line-interface-commands)
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- [Line breaks in interpolated strings](#line-breaks-in-interpolated-strings)
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- [Chapter 5](#chapter-5)
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- [List pattern matching](#list-pattern-matching)
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- [Chapter 8](#chapter-8)
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- [Regular Expressions](#regular-expressions)
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- [New content for .NET 7 Preview 3 (April)](#new-content-for-net-7-preview-3-april)
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- [New content for .NET 7 Preview 4 (May)](#new-content-for-net-7-preview-4-may)
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- [New content for .NET 7 Preview 5 (June)](#new-content-for-net-7-preview-5-june)
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- [New content for .NET 7 Preview 6 (July)](#new-content-for-net-7-preview-6-july)
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- [New content for .NET 7 Preview 7 (August)](#new-content-for-net-7-preview-7-august)
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- [New content for .NET 7 Release Candidate 1 (September)](#new-content-for-net-7-release-candidate-1-september)
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# New content for .NET 7 Preview 2
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## Chapter 1
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### Command Line Interface commands
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In .NET 7 Preview 2 and later, `dotnet` commands do not need to be prefixed with hyphens.
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For example, to list the currently installed templates before:
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```
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dotnet new --list
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```
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After:
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```
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dotnet new list
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```
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> Since I want to ensure that .NET 6 developers can follow the examples in the book, and Microsoft will support the use of hyphenated commands for a while, the book will continue to use the hyphenated commands but with a note that they are optional in .NET 7 and later.
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### Line breaks in interpolated strings
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One of my favorite new language features because it helps with printed code!
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Before C# 11, breaking an interpolated string in the middle of the double-quotes or in the middle of a curly-brace expression gives compile errors, as shown in the following code:
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```cs
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string message1 = $"Total number of
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fruit is {apples.Count}.";
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string message2 =
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$"Total number of fruit is {apples.Count
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+ oranges.Count}";
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```
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With C# 11, the above will compile. Finally!
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## Chapter 5
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### List pattern matching
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## Chapter 8
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### Regular Expressions
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In .NET 7 Preview 2 and later, you can use a more efficient Regex source generator.
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Before:
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```cs
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public class Foo
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{
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public Regex regex = new Regex(@"abc|def", RegexOptions.IgnoreCase);
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public bool Bar(string input)
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{
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bool isMatch = regex.IsMatch(input);
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// ..
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}
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}
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```
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After:
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```cs
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public partial class Foo // <-- Make the class a partial class
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{
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[RegexGenerator(@"abc|def", RegexOptions.IgnoreCase)] // <-- Add the RegexGenerator attribute and pass in your pattern and options
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public static partial Regex MyRegex(); // <-- Declare the partial method, which will be implemented by the source generator
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public bool Bar(string input)
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{
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bool isMatch = MyRegex().IsMatch(input); // <-- Use the generated engine by invoking the partial method.
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// ..
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}
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}
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```
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# New content for .NET 7 Preview 3 (April)
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# New content for .NET 7 Preview 4 (May)
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# New content for .NET 7 Preview 5 (June)
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# New content for .NET 7 Preview 6 (July)
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# New content for .NET 7 Preview 7 (August)
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# New content for .NET 7 Release Candidate 1 (September)
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