How to build an API using C# programming language

Introduction

Developing APIs can be a daunting task for developers who have no experience in making them. If you are new to the C# programming language, then building an API may look like rocket science. But it doesn't have to be! In this brief guide, we will show you how to build an API using C# programming language in just five steps.

Create a new project

• Create a new project

• Create a new class library

• Name the project and library as you desire

Step 1: Open Visual Studio, then go to File -> New Project.

Step 1: Open Visual Studio, then go to File -> New Project.

Step 2: Choose the project type: Class Library (.NET Core).

Step 3: Give your new project a name, then click OK.

Step 2: Create a class library project for .Net Core 3.0

To add the required assemblies, right-click on your project and select Properties. In the Solution Explorer window that opens up, click on the References tab.

• Add a reference to System.Net.Http (this is required for our tutorial) by selecting it from this list or by typing it into search bar at top of Solution Explorer view pane:

• Add a reference to Microsoft.AspNetCore.* packages (these packages contain all needed components for building an API):

• Select Microsoft ASP .NET MVC 5 Framework package in this list of available frameworks and press enter key on keyboard to automatically select it as well as other components such as Entity Framework Core or Razor Rendering Engine which we do not need here so just leave them unchecked here; then go back again without making any changes yet!

Step 3: Add Nuget packages

You can add Nuget packages to your project using NuGet. The following code shows how:

using Microsoft.AspNetCore.Web;

public class Program { public static void Main(string[] args) { CreateWebHostBuilder(args).Build().Run(); } }

Step 4: Create the model classes

Now that you've created your API, it's time to create the model classes. These are the classes that represent the data sent to and from the API.

When creating model classes, remember that they should be able to handle any kind of input data and return any kind of output data. They don't need to be very complex; if they're not complicated enough for what we want them for, then this is an indication that we should add more functionality or have another layer in front of them (such as an ORM).

Step 5: Configure your startup class

Now that you have created a Startup class and configured it, we can move on to creating our API.

Before we do so, however, you need to import Microsoft.AspNetCore.App into your project folder. This will allow us access to all of the various classes available in this package:

import Microsoft . AspNetCore . App ;

Step 6: Create the web API controller class

Now that you have your API, it's time to create the controller class. To do this, right-click on the project and select Add -> New Item...

In the Add New Item window (shown below), select Class and enter "WebApiController". The name of your controller will be different depending on what type of project you are creating. For example: If you want to build an ASP.NET MVC application then name it "WebApiController". In this case we are going with C# so our name should be WebApiControllerCS.

Now select OK in order for Visual Studio 2017 to create a new file called WebApiControllerCS.

Step 7: Consuming the Web API with Postman or Fiddler

With your API configured, you're ready to test it. You can use Postman or Fiddler to make requests from a web browser, but we'll be going over the steps for Postman since it's easier to use and more widely available.

• Start by creating a new request in Postman by clicking on Request Builder under the main menu at the top of your screen (the button with three arrows). This will open up an empty window where you can enter some information about your request, such as:

• URL - Enter https://api-test/my-endpoint here; this is where we'll be sending data from our app later on when we call back into our backend system via curl command line utility:

https://api-test/my-endpoint?key=&value=.

• Content type - This needs to be set as application/json because that's what all responses will be returned in if they were successful while making calls using curl , which is what we'll be using shortly after testing out this endpoint method with POSTMAN'S DEFAULT CURL OPTIONS SETTING!

This is a quick guide that gets you started building an API with C# programming Language

• Introduction:

An API (Application Programming Interface) is a set of tools and standards that developers can use to build their applications. It allows you to create a software interface between two or more applications, so that they can share information. The purpose of an API is to make it easier for other people to develop software that interacts with your application or service.

• What is C#?

C# is a programming language used by Microsoft for building Windows apps, web apps and basically any kind of software where you want full control over how things work inside the computer itself (and not just on its surface). It also comes with all kinds of libraries which makes it easy for developers who don't know anything about programming at all because there are many resources available online which will teach anyone how everything works using these libraries!

Conclusion

We hope this guide has helped you get started building an API with C#, but if you have any questions or need more help let us know in the comments section below!