Prerequisites

To get started, you will need to ensure that you have a few prerequisites installed. Then we will see how to create a real-time ASP.NET Core 3.0 chat application.

Visual Studio

If you want to use Visual Studio, ensure that you have Visual Studio 2019 with the ASP.NET and web development workload installed.

Note: Workloads allow you to modify Visual Studio to include additional components for development.

To get to your workloads, you need to use the Visual Studio Installer.

Figure 7: Launch Visual Studio Installer

Once the Visual Studio Installer is open, it will display all the installed versions of Visual Studio. Select the Visual Studio 2019 version (I say this because you might have a preview version of Visual Studio 2019 installed) and click Modify.

Figure 8: Installed Apps

This will display all the available workloads for you. You can view individual components, workloads, language packs, and installation components. Check the ASP.NET and web development workload check box and click Modify.

Figure 9: Visual Studio 2019 Workloads

In Figure 9, the screenshot does not display the Modify button because I already have the ASP.NET and web development workload installed. If you check a workload that isn’t installed on your machine, the button at the bottom of the workloads screen will change, as shown in Figure 10.

Figure 10: Modify Button on Workloads Screen

With the ASP.NET and web development workload installed, you need to make sure that you have the .NET Core 3.0 SDK or later installed. To do this, open your Command Prompt, and type dotnet --list-sdks, and select Enter.

Figure 11: Command Prompt Listing .NET Core SDKs

This will list the .NET Core SDKs currently installed on your system. If you don’t see the .NET Core 3.0 SDK or later installed, you need to head over to the download page for the current version of .NET Core (here at the time of writing).

Visual Studio Code

If you want to use Visual Studio Code, head on over to the Visual Studio Code downloads page  and grab a copy of the version for the system you are using (here at the time of writing).

Figure 12: Download Visual Studio Code

Visual Studio Code users will also need to install the latest version of C# for Visual Studio Code. You can install it from the marketplace, or from within Visual Studio Code via the Extensions tab.

With Visual Studio Code open, press Ctrl+Shift+X and search for C#. You will see that the first result displayed is C# for Visual Studio Code by Microsoft (see Figure 13).

Figure 13: Visual Studio Code Extensions

Visual Studio Code users also need to install the .NET Core 3.0 SDK or later.

Note: The previous section on Visual Studio explains how to download and install the .NET Core 3.0 SDK.

Users on Mac can also use Visual Studio for Mac. Let’s have a look at the prerequisites for that next.

Visual Studio for Mac

If you want to run Visual Studio on your Mac to develop real-time ASP.NET Core applications using SignalR, you will need to download Visual Studio 2019 for Mac first.

You can download Visual Studio for Mac from this page, where you can also see a comparison between Visual Studio 2019 and Visual Studio 2019 for Mac.

Along with Visual Studio 2019 for Mac, you will need to install the .NET Core 3.0 SDK or later.

Note: The previous section on Visual Studio explains how to download and install the .NET Core 3.0 SDK.

Once you have all the prerequisites and components downloaded and installed, you are ready to create your web application.