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docs/errata/README.md
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If you find any mistakes in the seventh edition, *C# 11 and .NET 7 - Modern Cross-Platform Development Fundamentals*, or if you have suggestions for improvements, then please [raise an issue in this repository](https://github.com/markjprice/cs11dotnet7/issues) or email me at markjprice (at) gmail.com.
[**Errata** (49 items)](errata.md): Typos, tool user interface changes, or mistakes in code that would cause a compilation error that prevents a successful build.
[**Errata** (50 items)](errata.md): Typos, tool user interface changes, or mistakes in code that would cause a compilation error that prevents a successful build.
[**Improvements** (44 items)](improvements.md): Changes to text or code that would improve the content. These are optional.

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docs/errata/errata.md
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**Errata** (49 items)
**Errata** (50 items)
If you find any mistakes, then please [raise an issue in this repository](https://github.com/markjprice/cs11dotnet7/issues) or email me at markjprice (at) gmail.com.
@ -47,6 +47,7 @@ If you find any mistakes, then please [raise an issue in this repository](https:
- [Page 477 - Inserting entities](#page-477---inserting-entities)
- [Page 478 - Updating entities](#page-478---updating-entities)
- [Page 495 - Filtering entities with Where](#page-495---filtering-entities-with-where)
- [Page 515 - Be careful with Count!](#page-515---be-careful-with-count)
- [Page 548 - Creating a class library for a Northwind database context](#page-548---creating-a-class-library-for-a-northwind-database-context)
- [Page 550 - Creating a class library for entity models using SQL Server](#page-550---creating-a-class-library-for-entity-models-using-sql-server)
- [Page 551 - Creating a class library for entity models using SQL Server](#page-551---creating-a-class-library-for-entity-models-using-sql-server)
@ -663,6 +664,27 @@ WriteLine($"Increase price success for ID: {resultUpdate.productId}.");
In Steps 3 and 5, the screenshots in *Figure 11.1* and *Figure 11.2* show a solution name of **Chapter12** when it should be **Chapter11**. In the next edition, I will retake the screenshots.
# Page 515 - Be careful with Count!
> Thanks to Clint Mayers who submitted this issue via email.
I showed a code teaser by Amichai Mantinband, a software engineer at Microsoft, as shown in the following code:
```cs
IEnumerable<Task> tasks = Enumerable.Range(0, 2)
.Select(_ => Task.Run(() => Console.WriteLine("*")));
await Task.WhenAll(tasks);
Console.WriteLine($"{tasks.Count()} stars!");
```
But the `WriteLine` methods should have been `Write` methods, as shown in the following code:
```cs
IEnumerable<Task> tasks = Enumerable.Range(0, 2)
.Select(_ => Task.Run(() => Console.Write("*")));
await Task.WhenAll(tasks);
Console.Write($"{tasks.Count()} stars!");
```
# Page 548 - Creating a class library for a Northwind database context
In Step 11, you write an extension method that registers the `NorthwindContext` class for use as a dependency service. In later chapters, this will be used in ASP.NET Core and Blazor projects. By default, a `DbContext` class is registered using `Scope` lifetime, meaning that multiple threads can share the same instance. If more than one thread attempts to use the same `NorthwindContext` class instance at the same time then you will see the following runtime exception thrown: