ASP NET Core Web API 2025
ASP.NET Core is a new open-source, cross-platform framework for developing modern cloud-based internet-connected applications like web, IoT, and mobile backends. Apps written in ASP.NET Core can run on either.NET Core or the full.NET Framework. It was designed to provide an optimized development framework for programs that run on-premises or in the cloud. It’s modular components with low overhead, giving you more options when building solutions. Your ASP.NET Core apps can be developed and operated on Windows, Mac, and Linux. The source code for ASP.NET Core is available on GitHub. ASP.NET Core is an evolution of ASP.NET, which first appeared in January 2002, during the dot-com bubble. The initial release of ASP.NET was a free package for web development on Windows servers. Today, there are three major versions of ASP.NET
The architectural improvements in ASP.NET Core result in a significantly leaner and modular framework. The system is no longer used in ASP.NET Core. Web.dll. It’s built on a foundation of well-factored NuGet packages. It lets you optimize your program by including the NuGet packages you require. Tighter security, reduced servicing, improved performance, and lower expenses in a pay-for-what-you-use model are advantages of a smaller app surface area. The ASP.NET Core team designed their framework specifically to create cloud-ready apps that run anywhere. They wanted to create a framework that developers and IT administrators could use with confidence, even if they didn’t know how to write code themselves.
ASP.NET Core 1.0 was released in December 2016, with the launch of Visual Studio 2017 not long after. That same month, Microsoft announced an SDK for .NET Standard 2.0, which enables cross-platform apps written in C#/VB or JavaScript for all major platforms:
- Desktop, mobile, and IoT devices via browsers and client apps such as iOS and Android apps
- Windows 10, Windows Server, or SQL Server applications using a Microsoft Graph API
- Web applications running on the Kestrel webserver
Free ASP.NET Core Practice Online Test
ASP.NET Core validation DropdownList
The ASP.NET Core Dropdown List can be used to quickly replace HTML select tags. It has a rich design and lets users choose from a list of predetermined values a single non-editable value. Data binding, filtering, grouping, UI customization, accessibility, and preselected values are all included out of the box. The DropdownList is a flexible, easy to use control and can be used in many different scenarios. For example, you can use it to populate a drop-down or text box. Just bind an object property to the DataSource property of the DropdownList, and then set the SelectedValue to the desired value in your view model.
There are two ways to validate a DropDownList value:
1. Validation Rules
By adding validation properties to the input element, validation rules assist you in verifying the selected text. The ValidationRules property can be used to set this. You may use any of the built-in validation rules or create your own.
2. Messages of Validation
The ValidationMessage property allows you to create your own unique error message. Specify the corresponding annotation attribute followed by the message to display the error message.
The DropdownList allows you to bind an object property to the DataSource property of the DropDownList, and after that, set the SelectedValue to a value in your view model. If not set prior, the selected value will be initialized by default with a default option ”.
| What is ASP.NET Core? | ASP.NET Core is a cross-platform, open-source framework for building modern web applications and APIs, designed to run on Windows, Linux, and macOS. |
| What is the difference between ASP.NET and ASP.NET Core? | ASP.NET Core is a more lightweight, modular, and cross-platform version of ASP.NET, offering improved performance and a more flexible architecture. |
| Why should I use ASP.NET Core? | ASP.NET Core provides better performance, enhanced security, cross-platform compatibility, and cloud-ready features for modern web applications. |
| Is ASP.NET Core free to use? | Yes, ASP.NET Core is open-source and free to use, with full access to its source code through GitHub. |
| What is the ASP.NET Core exam format? | The ASP.NET Core exam typically includes multiple-choice questions, coding exercises, and design pattern challenges covering web development topics and best practices. |
| How long is the ASP.NET Core exam? | The exam lasts approximately 2-3 hours, depending on the specific test and the number of questions or exercises. |
| How many questions are on the ASP.NET Core exam? | The exam typically includes 50-70 questions, depending on the specific certification level or provider. |
| What is the passing score for the ASP.NET Core exam? | The passing score is typically 70% or higher, though this may vary depending on the specific exam provider. |
| How do I register for the ASP.NET Core exam? | Register for the ASP.NET Core exam through the official certification provider's website, such as Microsoft or other accredited certification bodies. |
| What documents are required to register for the ASP.NET Core exam? | You will need a valid ID, a computer with internet access, and an account with the exam provider to register and schedule the test. |
| Can I take the ASP.NET Core exam online? | Yes, some certification providers offer online proctored exams, allowing you to take the test from home or a remote location. |
| How much does the ASP.NET Core exam cost? | The cost of the ASP.NET Core exam typically ranges from $100 to $250, depending on the certification level and provider. |
| How is the ASP.NET Core exam scored? | The exam is scored based on correct answers, with most certification providers using a scaled score that reflects your overall performance. |
| When will I receive my ASP.NET Core exam results? | Exam results are typically available immediately or within 24 hours after completing the test, depending on the provider. |
| Can I retake the ASP.NET Core exam if I fail? | Yes, you can retake the exam after a waiting period, typically 14 to 30 days, and you may need to pay the exam fee again. |
| How long is the ASP.NET Core exam valid for? | The ASP.NET Core certification is usually valid for 2-3 years before needing to be renewed or recertified. |
| How should I prepare for the ASP.NET Core exam? | Prepare by studying official documentation, taking practice tests, and using online courses or boot camps that focus on ASP.NET Core development. |
| What resources should I use to study for the ASP.NET Core exam? | Utilize official Microsoft learning paths, online tutorials, and practice exams to reinforce your knowledge and skills in ASP.NET Core. |
| How long should I study for the ASP.NET Core exam? | The recommended study time is 4-6 weeks, depending on your familiarity with ASP.NET Core and the exam's complexity. |
| Is there a study guide for the ASP.NET Core exam? | Yes, many study guides are available online, including official Microsoft study materials and third-party study guides for ASP.NET Core certification exams. |
ASP.NET Core allowedhosts
allowedHosts is used to bind your app to specific hostnames using host filtering. It is used to run your app on a specific port.
ASP.NET Core MVC will listen for incoming requests on all interfaces, using port number 5000 by default. But you can use the HostName property to limit your app’s listening interface or port number. You can use allowedHosts in conjunction with host-based routing to route requests based on the client’s address, user identity, or server name.
ASP.NET Core drag and drop
The Microsoft ASP.NET Core MVC Drag and Drop widget can help you add drag-and-drop functionality to your modern and intuitive application. The widget works best with the handler attribute on your data-bound controls, which allows you to programmatically determine when the user has started dragging data from a source into your control.
You can use the attribute anytime during your application process, including within data binding expressions or even in your controller action. You can also dynamically change the dragged object using an embedded ViewModel and methods such as SetDragImage and SetLiftedImage. You’ll be able to use the new ASP.NET Core drag and drop functionality by moving an image from one side of your application to the other. You first bind the source image tag in your view to your source property in your model.
When you move your mouse over it, a cursor change occurs, and you may use the handler attribute to link this event to a method on your controller. This function is called as soon as you start dragging an object from one side of your application to another, providing both the source and target objects for you to perform some custom logic when an object is being dragged around.
When dropping an object, two events are raised: DragDropEnd and DragDropStarted.
ASP.NET Core FromForm
The FromForm element is for incoming data from a submitted form sent with the content type application/x-www-form-urlencoded, whereas the FromBody attribute parses the model from the request body in the default fashion, which is usually sent with the content-type application/json. The FromForm attribute specifies that the data for a model is obtained from a form field.
You can easily bind the form field names for the data source to your model properties. You also need to set up content negotiation to tell ASP.NET MVC how to parse incoming requests as form content, JSON, or XML. You can use the attribute on your controller action or directly on your model property. However, it’s generally best to place it on a controller action if you’re using multiple actions per controller.
The basic idea behind this element is that you have one parameter whose value contains several parameters automatically forwarded to your model object as strongly typed parameter values using data binding.
ASP.NET Core MariaDB
One of the most popular open-source relational databases is MariaDB Server. It was created by the original MySQL developers and is promised to remain open source. Most cloud providers use it, and most Linux distributions use it by default. Therefore, it can be considered a default choice for developers. You can easily use Microsoft’s Entity Framework Core to utilize MariaDB’s full support for SQL Standards compliance easily. The protocol is based on the open standards JDBC, SQL/CLI, and ODBC.
ASP.NET Core message queue
Message queues provide asynchronous communication and processing between different portions of a system. We can separate the operation, disconnect the services, and scale independently in this fashion. We can handle huge loads and distribute the system’s components without hindering performance or availability. You can use message queues to communicate within a web application, across different services, and even external systems.
The message queue is a centralized container for messages delivered to recipients in a predefined sequence. In other words, you put data in a queue, and it’s then processed by some consumer later, asynchronously. A popular choice for ASP.NET Core is RabbitMQ.
ASP.NET Core server side rendering
Server-Side Rendering (SSR) is a technique used to prerender and cache the page content on the server-side when a request comes in. In other words, you can use it to process the page at the server-side after receiving the first request and send back HTML markup as a response. You can use it to implement a demo or a working application. You need to include the script tag that contains the markup of the page you want to prerender and cache.
The capacity of an application to turn HTML files on the server into a fully rendered HTML page for the client is known as server-side rendering (SSR). The web browser sends a request for information to the server, answering immediately by delivering a completely displayed page to the client. This approach is a good choice for small, simple applications that don’t require a lot of HTML markup. For example, you might use server-side rendering when you’re using lightweight templates instead of JavaScript frameworks like Angular: they are less demanding on your server resources because they don’t render much content.
The primary idea behind SSR is that the same page may be provided to several clients without having to be rendered on each one. Using a virtual function called prerendering, we can prerender and cache the page content on the server before sending the first request to our client application. This happens behind the scenes and doesn’t require us to modify any code.
Chart JS ASP.NET Core
With Chart.js, getting started is simple. To render the chart, all you need is the script included in your page and a single <canvas> node. Chart.js is suitable for fast data visualization, and it’s highly customizable.
You can include the script file on your page, specify the parameters for your chart (type, data, options), and draw it all with a single method, .render().
The chart is a powerful JavaScript library that makes interactive charts on the web easy. It’s simple, flexible, and fun to use. You can create anything from simple line charts and bar charts to complex geographic maps or real-time stock charts. Chart supports responsive design, so you can easily adapt it to any screen size without sacrificing quality or performance. The library is compatible with any CMS framework and offers thousands of customization possibilities.
Datatable ASP.NET Core
The DataTable is a key component of the ADO.NET framework. The DataSet and the DataView are two further objects that use the DataTable. The DataTable contains columns, which can be of different types, including ADO.NET data types (such as string, int, or binary) and HTML entities.
A key feature of DataTables is the ability to add and remove properties from these tables at runtime (pagination). You can filter data based on specific criteria using an SQL-like syntax (select clause).
Responsecache ASP.NET Core
Response caching headers are set using the ResponseCache property. The HTTP 1.1 Caching standard requires clients and intermediate proxies to respect headers while caching replies. Response caching can reduce bandwidth usage and speed up delivery to clients by providing a local copy of frequently requested resources. ResponseCache uses the output from a standard HTML compression algorithm to optimize performance. It compresses the response content with GZIP and sends compressed data to the client.
RespondCache is an advanced server-side cache library that leverages ASP.NET Core’s built-in Caching framework to add caching capabilities to your application more easily. It’ll become handy when you need to cache responses from your web API, for example, and improve its performance by providing a local copy of frequently requested resources.
On ASP, Response Caching is also possible.
Scripts render ASP.NET Core
Scripts are very useful for implementing custom logic without coding. They automate tasks, render forms, generate content, and so on. .NET provides a ScriptManager class to facilitate access from views in an ASP.NET Core app by allowing you to inject Scripts into your page. Using .NET Core 2.0, you can use Visual Studio 2017 and the Razor syntax to create your scripts for page rendering and page navigation; otherwise, you can use the Script editor that ships with Visual Studio 2017.
View Components in ASP.NET Core MVC
View components in ASP.NET Core MVC are comparable to partial views, but they are far more powerful. View components don’t use model binding. Thus they rely only on the data you provide when calling them. It allows you to create reusable components that don’t depend on the model context.
As a simple example, you could use a ViewComponent to build an admin page that is rendered once and then cached. These help significantly reduce the amount of time it takes for users to see the page and reduce pressure on your back-end application.
The reason for this is that each ViewComponent has its independent lifecycle, which means that we can dispose of every control right after its execution and cleanup resources.
In contrast, Razor views are part of the global view state, and thus they keep all their resources in memory until they are released at the end of processing the request or until specific events occur (such as exceptions being thrown).
AdminLTE ASP.NET Core
The best open source admin dashboard and control panel theme is AdminLTE. The UI framework Bootstrap was utilized. AdminLTE comes with several responsive, reusable, and widely used components. These components are ready to use with your data and can easily be customized.
AdminLTE is a ready-made, open-source, Bootstrap 3 based admin control panel template. The jQuery and Angular versions are also available. It includes many HTML pages and CSS files that provide numerous ready-to-use components for creating web applications with ASP.NET MVC5 or ASP.NET Core 2.0, like CRUD operations with Views, Basic Login Page, or Responsive Tables and Chart Controls.
The AdminLTE template is designed for developers who want to create powerful web applications faster in an easy-to-use way with great UX/UI quality.
ASP.NET Core change port
In an ASP.NET Web API, navigate the launchSettings.json file under Properties to modify the port. The default port is 4222 (this can be changed manually on the ASP.NET Core command line without doing the update). The launchSettings.json file is the configuration file that Visual Studio uses to customize your ASP.NET Core Web API project. We add the app setting key under Package/Publish/Debug and set it to a string value representing the port number we want to use.
ASP.NET Core Questions and Answers
Check your system requirements and ensure you have the correct version of .NET SDK installed. Refer to error logs for detailed troubleshooting steps.
ASP.NET Core requires the .NET SDK, a supported version of Visual Studio, and a compatible operating system (Windows, macOS, or Linux).
Use the `dotnet tool update` command to upgrade your ASP.NET Core modules and SDK to the latest version.
Uninstall ASP.NET Core modules using the `dotnet tool uninstall` command or by removing the packages from your project file.
Common errors include configuration issues, missing dependencies, incorrect versioning, and runtime environment problems.
Popular tools like Visual Studio, Visual Studio Code, Docker, and Git integrate seamlessly with ASP.NET Core for development.
To contribute to ASP.NET Core, fork the repository from GitHub, make changes, and submit a pull request to the official repository.
ASP.NET Core can be used offline after initial setup and installation, as long as the necessary dependencies are already available locally.
Use the `dotnet add package` command to search for and install specific ASP.NET Core modules from the NuGet repository.
The ASP.NET Core mirror network is a collection of servers worldwide that host the .NET SDK and runtime, ensuring fast and reliable downloads.