When creating custom exception middleware in ASP.NET Core, you should override the InvokeAsync method. This method allows you to intercept and handle exceptions that occur during the processing of an incoming HTTP request, providing an opportunity to customize error responses or perform other actions.

Razor views in ASP.NET Core typically have the ".cshtml" file extension. This extension signifies that the view contains both HTML markup and C# code, making it easy to create dynamic web pages that can interact with server-side data and logic.

To specify the SDK version for a .NET project, you should add a global.json file to the project directory. This file allows you to pin the SDK version, ensuring that all team members use the same version, promoting consistency in the development environment.

Integration tests in ASP.NET Core usually concentrate on assessing the interaction and integration between various components, such as database interactions, service integrations, or API calls, within the application. In contrast, end-to-end tests evaluate the application's complete functionality, including its user interface, as if a user were interacting with it.

Azure App Service is a cloud-based deployment option offered by Microsoft Azure that provides managed hosting services for ASP.NET Core applications. It abstracts infrastructure management, allowing developers to focus on their code and application logic while benefiting from features like scalability, security, and easy deployment.

In Entity Framework Core, the process of creating a command that can update the database to reflect the current model is called "Migrations." Migrations enable you to evolve your database schema as your application's data model changes over time.

To ensure that all components of a web application work together seamlessly, you should focus on End-to-End Testing. This type of testing validates the flow of an application from start to finish and ensures that all integrated components function correctly in a real-world scenario.

To restrict an action method to only accept HTTP POST requests, you should decorate the action method with the [HttpPost] attribute. This attribute ensures that the method can only be invoked when an HTTP POST request is made to it.

In ASP.NET Core, to add user secrets in a development environment without affecting the main configuration files, you would typically use the "User Secrets Manager" or the "dotnet user-secrets" command-line tool. This tool allows developers to store sensitive configuration data securely during development without checking them into source control. It's a best practice to separate secrets from code and configuration files.

The Unit of Work pattern is used in Entity Framework Core to batch multiple database operations together. It helps improve performance and ensures that changes are only persisted to the database when the entire unit of work is completed successfully.