Looking for help

This section is all about how to find quality information about programming on the web.

Microsoft Learn documentation and Ask Learn

The definitive resource for getting help with Microsoft developer tools and platforms is in the technical documentation on Microsoft Learn, and you can find it at the following link: https://learn.microsoft.com/en-us/docs.

“One of the most ambitious and impactful projects our engineers have built recently is Ask Learn, an API that provides generative AI capabilities to Microsoft Q&A.” - Bob Tabor, Microsoft’s Skilling organization

You can read about it at the following link:

https://devblogs.microsoft.com/engineering-at-microsoft/how-we-built-ask-learn-the-rag-based-knowledge-service/

Documentation links in this book

The official Microsoft documentation for .NET needs to cover all versions. The default version shown in the documentation is always the most recent GA version.

For example, between November 2024 and November 2025, the default version of .NET shown in the documentation pages will be for .NET 9. Between November 2025 and November 2026, the default version of .NET will be for .NET 10. The following link will automatically direct to the current version, depending on the current date:

https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.stringsyntaxattribute

After November 2025, to view the documentation page specifically for .NET 9, append ?view=net-9.0 to the end of a link. For example, use the following link:

https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.stringsyntaxattribute?view=net-9.0

All documentation links in this book do not specify a version. If you want to force the documentation to show the version for .NET 8 because you need to target an LTS version (three years) instead of .NET 9, which is an STS version (18 months), then append ?view=net-8.0 to the end of a link.

You can check what versions a .NET feature supports by appending #applies-to to the end of a link, for example:

https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.stringsyntaxattribute#applies-to

We can, therefore, see that the StringSyntax attribute is only available in .NET 7 or later.

Getting help from the dotnet tool

At the command prompt, you can ask the dotnet tool for help with its commands. The syntax is:

dotnet help <command>

This will cause your web browser to open a page in the documentation about the specified command. Common dotnet commands include new, build, run, and many more.

Warning! The dotnet help new command worked with .NET Core 3.1 to .NET 6, but it returns an error with .NET 7 or later: Specified command 'new' is not a valid SDK command. Specify a valid SDK command. For more information, run dotnet help. Hopefully, .NET will fix that bug soon!

Another type of help is command-line documentation. It follows this syntax:

dotnet <command> -?|-h|--help

For example, dotnet new -? or dotnet new -h or dotnet new --help outputs documentation about the new command at the command prompt.

As you should now expect, dotnet help help opens a web browser for the help command, and dotnet help -h outputs documentation for the help command at the command prompt!

Let’s try some examples:

1. To open the official documentation in a web browser window for the dotnet build command, enter the following at the command prompt or in the VS Code terminal, and note the page opened in your web browser:

   dotnet help build
   

2. To get help output at the command prompt, use the -? or -h or --help flag, as shown in the following command:

   dotnet build -?
   

3. You will see the following partial output:

   Description:
     .NET Builder
   Usage:
     dotnet build [<PROJECT | SOLUTION>...] [options]
   Arguments:
     <PROJECT | SOLUTION>  The project or solution file to operate on. If a file is not specified, the command will search the current directory for one.
   Options:
     --ucr, --use-current-runtime         Use current runtime as the target runtime.
     -f, --framework <FRAMEWORK>          The target framework to build for. The target framework must also be specified in the project file.
   ...
     -?, -h, --help                       Show command line help.
   

4. Repeat both types of help requests for the following commands: add, help, list, new, and run, remembering that new might not show its web page, due to a bug introduced in .NET 7.

Getting definitions of types and their members

One of the most useful features of a code editor is Go To Definition (F12). It is available in VS Code, Visual Studio, and Rider. It will show what the public definition of the type or member looks like by reading the metadata in the compiled assembly.

Some tools, such as ILSpy .NET Decompiler, will even reverse-engineer the metadata and IL code back into C# or another language for you.

A similar and related feature is named Go To Implementation (Ctrl + F12). Instead of reading the metadata or decompiling, this will show the actual source code if that is embedded, using the optional source link feature.

Warning! Go To Definition should go to the decompiled metadata for a member or type. But if you have previously viewed the source link, then it goes to that. Go To Implementation should go to the source link implementation for a member or type. But if you have disabled the source link, then it goes to the decompiled metadata.

Let’s see how to use the Go To Definition feature:

1. In your preferred code editor, open the solution/folder named Chapter01.

If you are using Visual Studio:

• Navigate to Tools | Options.
• In the search box, enter navigation to source.
• Select Text Editor | C# | Advanced.
• Clear the Enable navigation to Source Link and Embedded sources checkbox, and then click OK, as shown in Figure 1.11:

Figure 1.11: Disabling Source Link for the Go To Definition feature

Definitions can be either reverse-engineered from metadata or loaded from the original source code if that is enabled. Personally, I find the code from metadata more useful, as you are about to see. At the end of this section, try switching the Source Link option back on to see the difference.

2. In the HelloCS project, at the bottom of Program.cs, enter the following statement to declare an integer variable named z:

   int z;
   

3. Click on int, right-click on int, and then choose Go To Definition in Visual Studio or VS Code. In Rider, choose Go to | Go to Declaration or Usages.
4. In the code window that appears, you can see how the int data type is defined, as shown in the following code:

   #region Assembly System.Runtime, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
   // C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\9.0.0\ref\net9.0\System.Runtime.dll
   #endregion
   #nullable enable
   using System.Diagnostics.CodeAnalysis;
   using System.Globalization;
   using System.Numerics;
   using System.Runtime.CompilerServices;
   namespace System
   {
     public readonly struct Int32 : IComparable,
       IComparable<Int32>, IConvertible, ...
     {
       public const Int32 MaxValue = 2147483647;
       public const Int32 MinValue = -2147483648;
       ...
     }
   }
   

You can see that int:

• Is defined using the struct keyword.
• Is in the System.Runtime assembly.
• Is in the System namespace.
• Is named Int32.
• Is, therefore, an alias for the System.Int32 type.
• Implements interfaces such as IComparable.
• Has constant values for its maximum (2147483647) and minimum (-2147483648) values.
• Has methods such as Parse (not visible in the preceding code).

Currently, the Go To Definition feature is not that useful to you because you do not yet know what all of this information means. By the end of the first part of this book, which consists of Chapters 2 to 6 and teaches you about the C# language, you will know enough for this feature to become very handy.

5. In the code editor window, scroll down to find the Parse method with a single string parameter, as shown in the following code:

   public static Int32 Parse(string s)
   

6. Expand the code and review the comments that document this method, as shown in Figure 1.12:

Figure 1.12: The comments for the Parse method with a single string parameter

In the comments, you will see that Microsoft has documented the following:

• A summary that describes the method.
• Parameters like the string value that can be passed to the method.
• The return value of the method, including its data type.
• Three exceptions that might occur if you call this method, including ArgumentNullException, FormatException, and OverflowException. Now, we know that we could choose to wrap a call to this method in a try statement and which exceptions to catch.

Configuring inline aka inlay hints

Throughout the code in this book, when calling a method, I often explicitly specify named parameters to help you learn what is going on. For example, I have specified the names of the parameters format and arg0 in the following code:

Console.WriteLine(format: "Value is {0}.", arg0: 19.8);

Inline hints, aka inlay hints, show the names of parameters without you having to type them, as shown in Figure 1.13:

Figure 1.13: Configuring inline hints, aka inlay hints

Most code editors have this feature, which you can enable permanently or only when a key combination like Alt + F1 or Ctrl is held down:

• In Visual Studio, navigate to Tools | Options, then Text Editor | C# | Advanced, scroll down to the Inline Hints section, select the Display inline parameter name hints checkbox, and then click OK.
• In VS Code, navigate to File | Preferences | Settings, search for inlay, select the C# filter, and then select the Display inline parameter name hints checkbox.
• In Rider, in Settings, navigate to Editor | Inlay Hints | C# | Parameter Name Hints.

Hopefully, you are getting impatient to learn what all this means!

Be patient for a little longer. You are almost at the end of this chapter, and in the next chapter, you will dive into the details of the C# language. But first, let’s see where else you can look for help.

Looking for answers on Stack Overflow

Stack Overflow is the most popular third-party website for getting answers to difficult programming questions. Let’s see an example:

1. Start your favorite web browser.
2. Navigate to stackoverflow.com; in the search box, enter securestring and note the search results.

Searching for answers using Google

You can search Google with advanced search options to increase the likelihood of finding what you need:

1. Navigate to Google at the following link: https://www.google.com/.
2. Search for information about garbage collection using a simple Google query, and note that you will probably see a lot of ads for garbage collection services in your local area before you see the Wikipedia definition of garbage collection in computer science!
3. Improve the search by restricting it to a useful site such as Stack Overflow, by removing languages that we might not care about, such as C++, Rust, and Python, or by adding C# and .NET explicitly, as shown in the following search query:

   garbage collection site:stackoverflow.com +C# -Java
   

Getting help on Discord and other chat forums

Asking questions in programming forums and Discord channels is an art as much as it is a science. To maximize your chances of receiving a helpful answer, there’s a blend of clarity, specificity, and community awareness that you should aim for.

Here are some tips for asking questions:

• Ask in a public channel, not in private. Please do not direct message an author with a question or a friend request. Remember, every question asked and answered builds the collective knowledge and resourcefulness of the whole community. Asking in public also allows other readers to help you, not just the author. The community that Packt and I have built around my books is friendly and smart. Let us all help you.
• Research before asking: It’s important to look for answers yourself before turning to the community. Use search engines, official documentation, and the search function within the forum or Discord server. This not only respects the community’s time but also helps you learn more effectively. Another place to look first is the errata and improvements section of the book, found at the following link: https://github.com/markjprice/cs13net9/blob/main/docs/errata/README.md.
• Be specific and concise: Clearly state what you’re trying to achieve, what you’ve tried so far, and where you’re stuck. A concise question is more likely to get a quick response.
• Specify the book location: If you are stuck on a particular part of the book, specify the page number and section title so that others can look up the context of your question.
• Show your work: Demonstrating that you’ve made an effort to solve the problem yourself not only provides context but also helps others understand your thought process and where you might have gone down a wrong path.
• Prepare your question: Avoid too broad or vague questions. Screenshots of errors or code snippets (with proper formatting) can be very helpful.

  Oddly, I’ve been seeing more and more examples of readers taking photos of their screens and posting those. These are harder to read and limited in what they can show. It’s better to copy and paste the text of your code or the error message so that others can copy and paste it themselves. Alternatively, at least take a high-resolution screenshot instead of a photo with your phone camera at a jaunty angle!

• Format your code properly: Most forums and Discord servers support code formatting using Markdown syntax. Use formatting to make your code more readable. For example, surround code keywords in single backticks, like `public void`, and surround code blocks with three backticks with optional language code, as shown in the following code:

  ```cs
  using static System.Console;
  WriteLine("This is C# formatted code.");
  ```
  

  Good Practice: After the three backticks that start a code block in Markdown, specify a language short name like cs, csharp, js, javascript, json, html, css, cpp, xml, mermaid, python, java, ruby, go, sql, bash, or shell.

More Information: To learn how to format text in Discord channel messages, see the following link: https://support.discord.com/hc/en-us/articles/210298617-Markdown-Text-101-Chat-Formatting-Bold-Italic-Underline.

• Be polite and patient: Remember, you’re asking for help from people who are giving their time voluntarily. A polite tone and patience while waiting for a response go a long way. Channel participants are often in a different time zone, so you may not see your question answered until the next day.
• Be ready to actively participate: After asking your question, stay engaged. You might receive follow-up questions for clarification. Responding promptly and clearly can significantly increase your chances of getting a helpful answer. When I ask a question, I set an alarm for three hours later to go back and see if anyone has responded. If there hasn’t been a response yet, then I set another alarm for 24 hours later.

Incorporating these approaches when asking questions not only increases your likelihood of getting a useful response but also contributes positively to the community, by showing respect for others’ time and effort.

Good Practice: Never just say “Hello” as a message on any chat system. You can read why at the following link: https://nohello.net/. Similarly, don’t ask to ask: https://dontasktoask.com/.

Searching the .NET source code

Sometimes, you can learn a lot from seeing how the Microsoft teams have implemented .NET. The source for the entire code base for .NET is available in public GitHub repositories. For example, you might know that there is a built-in attribute to validate an email address.

Let’s search the repositories for the word “email” and see if we can find out how it works:

1. Use your preferred web browser to navigate to https://github.com/search.
2. Click advanced search.
3. In the search box, type email.
4. In the In these respositories box, type dotnet/runtime. (Other repositories that you might want to search include dotnet/core, dotnet/aspnetcore, dotnet/wpf, and dotnet/winforms.)
5. In the Written in this language box, select C#.
6. At the top right of the page, note how the advanced query has been written for you. Click Search, then the Code filter, and note that the results include EmailAddressAttribute, as shown in Figure 1.14:

Figure 1.14: Advanced search for email in the dotnet/runtime repository

7. Click the source file, and note that it implements email validation by checking that the string value contains an @ symbol but not as the first or last character, as shown in the following code:

   // only return true if there is only 1 '@' character
   // and it is neither the first nor the last character
   int index = valueAsString.IndexOf('@');
   return
       index > 0 &&
       index != valueAsString.Length - 1 &&
       index == valueAsString.LastIndexOf('@');
   

8. Close the browser.

For your convenience, you can do a quick search for other terms by replacing the search term email in the following link: https://github.com/search?q=%22email%22+repo%3Adotnet%2Fruntime+language%3AC%23&type=code&ref=advsearch.

Source code in documentation

When you read API reference documentation, you often want to review the actual source code. For .NET APIs that have Source Link enabled, have an accessible PDB, and are hosted in a public GitHub repository, links to source code are included in the definition metadata. For example, the String class documentation page now has this new Source link, and its IndexOf method has a Source link to another of its source files, as shown in Figure 1.15:

Figure 1.15: Documentation with links to source files

You can read more about how the Microsoft team achieved this in the article Introducing links to source code for .NET API Docs, found at the following link: https://devblogs.microsoft.com/dotnet/dotnet-docs-link-to-source-code/.

Official .NET blog, standups, and news

To keep up to date with .NET, an excellent blog to subscribe to is the official .NET blog, written by the .NET engineering teams, and you can find it at the following link: https://devblogs.microsoft.com/dotnet/.

To watch .NET team members walk through previews of new features, you can watch monthly “standups,” available at the following link:

https://dotnet.microsoft.com/en-us/live/community-standup

You can subscribe to the latest .NET news at the following link:

https://github.com/dotnet/core/discussions/categories/news

Watching Scott Hanselman’s videos

Scott Hanselman from Microsoft has an excellent YouTube channel about computer stuff that they didn’t teach you at school: http://computerstufftheydidntteachyou.com/.

I recommend it to everyone working with computers.

AI tools like ChatGPT and GitHub Copilot

One of the biggest changes in coding and development in the past few years is the emergence of generative artificial intelligence (AI) tools that can help with coding tasks, like completing a code statement, implementing an entire function, writing unit tests, and suggesting debugging fixes for existing code.

You can read what developers say about AI tools in the 2023 Stack Overflow Developer Survey: “44% of them use AI tools in their development process now, and 26% plan to soon” (https://stackoverflow.blog/2023/06/14/hype-or-not-developers-have-something-to-say-about-ai/):

“From research to debugging to documentation, developers are using Generative AI to save time doing various tedious tasks at work. The biggest use case is writing code. This was how 82.55% of developers reported using Generative AI in the recent Stack Overflow Developer Survey.”

ChatGPT currently has several models for individuals: 4o mini (free), 4o (free but limited), and 4o with 5x more requests and other benefits, like early access to new features and DALL·E image generation ($20 per month). It also has pricing for enterprises. You can check their pricing at the following link: https://openai.com/chatgpt/pricing/.

ChatGPT example

Let’s say you need to write a C# function to validate an email address. You might go to ChatGPT and enter the following prompt:

write a c# function to validate an email address

It responds with a complete class with methods, as shown in Figure 1.16:

Figure 1.16: ChatGPT writes a function to validate an email address

It then provides an explanation of the code and examples of how to call the function, as shown in the following code:

bool isValid = EmailValidator.IsValidEmail("[email protected]");
Console.WriteLine(isValid ? "Valid" : "Invalid");

But is a general-purpose generative AI like ChatGPT the best partner for a C# programmer?

GitHub Copilot for programmers

Microsoft has a service specifically for programmers, named GitHub Copilot, that can help autocomplete code directly in your code editor. It has plugins for code editors, including Visual Studio, VS Code, and JetBrains IntelliJ-based IDEs.

Personally, I really like the Copilot branding. It makes it clear that you are the pilot. You are ultimately responsible for “flying the plane.” But for the easy or boring bits, you can hand it over to your co-pilot for a bit, while being actively ready to take back control if needed.

GitHub Copilot is free for students, teachers, and some open-source project maintainers. For everyone else, it has a 30-day free trial, and then it costs $10 per month or $100 per year for individuals. Once you have an account, you can then sign up for waiting lists to get the more advanced experimental GitHub Copilot features.

You should check online which Copilot features are available for various code editors. As you can imagine, this is a fast-changing world, and some of what I might write in the book today will be out of date by the time you read it: https://github.com/features/copilot.

JetBrains has its own GitHub Copilot equivalent, named AI Assistant, which you can read about at the following link: https://blog.jetbrains.com/idea/2023/06/ai-assistant-in-jetbrains-ides/.

So what can GitHub Copilot do for you today?

Imagine that you have just added a new class file named Product.cs. You click inside the Product class, press Enter to insert a blank line, and then pause for a second as you think about what you need to type… and then GitHub Copilot generates some sample code in gray, as shown in Figure 1.17:

Figure 1.17: GitHub Copilot suggesting how to define a Product class

At this point, you can glance over the code and, if it is close to what you want, just press Tab to insert it all, or press Alt + . (dot) to toggle between other suggestions.

Sometimes, it is too far from what you need, and you’d be better off ignoring its suggestion completely and just writing it yourself. But usually, there’s something there that’s usable or reminds you of the syntax you need to use. And sometimes, it feels like magic, writing dozens of lines of exactly what you need.

Microsoft feeds its AI tools with code from public GitHub repositories, including all the repositories I have created since 2016 for all the editions of this book. This means that it can suggest code completions for the readers of this book that are surprisingly accurate predictions, including my frequent use of pop culture references in my code. It’s like I, Mark J. Price, am the “ghost in the machine” guiding your coding.

It’s easy to imagine a custom ChatGPT that has ingested all the official Microsoft .NET documentation, every public blog article written about .NET, and perhaps even hundreds of books about .NET, and then having a conversation with it to find a bug or suggest how to solve a programming problem.

You can sign up for GitHub Copilot at the following link: https://github.com/github-copilot/signup/.

Good Practice: Learn more about how to use Copilot as your coding GPS at the following link: https://devblogs.microsoft.com/visualstudio/using-github-copilot-as-your-coding-gps/.

Here are some more links about using AI for coding:

• A Beginner’s Guide to Prompt Engineering with GitHub Copilot: https://dev.to/github/a-beginners-guide-to-prompt-engineering-with-github-copilot-3ibp
• The Register article about AI: https://www.theregister.com/2024/01/27/ai_coding_automatic/
• StackOverflow 2024 survey – Code editor / IDE: https://survey.stackoverflow.co/2024/technology#1-integrated-development-environment
• StackOverflow 2024 survey – AI search tools: https://survey.stackoverflow.co/2024/technology#1-ai-search-and-developer-tools

Disabling tools when they get in the way

Although these tools can be helpful, they can also get in your way, especially when learning, because they sometimes do work for you without telling you. If you do not do that work for yourself at least a few times, you won’t learn fully.

To configure IntelliSense for C# in Visual Studio:

1. Navigate to Tools | Options.
2. In the Options dialog box tree view, navigate to Text Editor | C# | IntelliSense.
3. Click the ? button in the caption bar to view the documentation.

To configure GitHub Copilot in Visual Studio:

1. Navigate to Tools | Options.
2. In the Options dialog box tree view, navigate to GitHub | Copilot.
3. Set Enable Globally to True or False, and then click OK.

To disable GitHub Copilot in VS Code:

1. In the status bar, on the right, to the left of the notification icon, click the GitHub Copilot icon.
2. In the popup, click Disable Globally.
3. To enable it, click the GitHub Copilot icon again and then click Enable Globally.

For help with Rider IntelliSense, please see the following link: https://www.jetbrains.com/help/rider/Auto-Completing_Code.html.