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Title: How to get JSON from an API and Process that Data
Content: <div class="row"> <div class="container"> <div class="col-md-12"> In this knowledge share I would like to show you how you can collect JSON from an external API, and then create C# classes and a Root object class that represent the JSON structure to process the data. I am using Visual Studio 2022 for this. The first section describes how to set up a console project. The second section shows the code that is needed to create a working example to collect and process JSON data from an API. <h2>Create a new C# Console Application</h2> <ol> <li>Open Visual Studio 2022.</li> <li>Select Create a new project. <img src="/images/articles/JSON-api/1.jpeg" alt="Create new Console Application in Visual Studio" class="img-thumbnail rounded"> </li> <li>Select Console App and then click Next. <img src="/images/articles/JSON-api/2.jpeg" alt="Select Console App in Visual Studio" class="img-thumbnail rounded"> </li> <li>In the Project Name field, type MyJsonApiTutorial and then click Next. <img src="/images/articles/JSON-api/3.jpeg" alt="Type in project name for Console App in Visual Studio" class="img-thumbnail rounded"> </li> <li>In the Framework field, select .NET 6.0 (Long Term Support) and then click Create. <img src="/images/articles/JSON-api/4.jpeg" alt="Select type of .NET framework to be used for the Console App in Visual Studio" class="img-thumbnail rounded"> </li> <li>Press the F5 key on your keyboard to test if the default application works. <img src="/images/articles/JSON-api/5.jpeg" alt="Default output of Console App" class="img-thumbnail rounded"> </li> <li>Press the Spacebar key on your keyboard to stop the Console Application. </li> <li>If not open already, open the file Program.cs in Visual Studio. </li> <li>Replace the existing code with the following code: <div class="overflow-auto"> <code> namespace MyJsonApiTutorial { internal class Program { static void Main(string[] args) { Console.WriteLine("Hello, from MyJsonApiTutorial"); Console.ReadKey(); } } } </code> </div> </li> <li>Press they F5 key to test if the modified application works. <img src="/images/articles/JSON-api/6.jpeg" alt="Default output of Console App" class="img-thumbnail rounded"> </li> </ol> <h2>Get Sample JSON Data to create Classes</h2> <ol> <li>In your Internet browser, open the website https://randomuser.me/api/. </li> <li>Copy the sample JSON that is shown in the Internet brower. Note:Your data sample will be different than that shown in the image. New data is created each time you open the web page.<img src="/images/articles/JSON-api/7.jpeg" alt="Sample JSON data" class="img-thumbnail rounded"> </li> <li>Open the website: https://json2csharp.com/. </li> <li>Make sure that the button JSON to C# is selected. See image. </li> <li>Paste the JSON data in the ‘JSON’ column on the left-hand side. <img src="/images/articles/JSON-api/8.jpeg" alt="Open website json2csharp" class="img-thumbnail rounded"> </li> <li>Click the Convert button. </li> <li>Copy the content in the right-hand column. <img src="/images/articles/JSON-api/9.jpeg" alt="Class content" class="img-thumbnail rounded"> </li> <li>in Visual Studio, right-click the project name to select Add > Class. <img src="/images/articles/JSON-api/14.jpeg" alt="Add Class" class="img-thumbnail rounded"> </li> <li>In the Name field, type User.cs and click Add. <img src="/images/articles/JSON-api/10.jpeg" alt="Add Class dialog" class="img-thumbnail rounded"> </li> <li>In the User.cs file remove the User class. <img src="/images/articles/JSON-api/11.jpeg" alt="Remove User Class" class="img-thumbnail rounded"> </li> <li>Paste the Class data in User.cs <img src="/images/articles/JSON-api/12.jpeg" alt="Paste generated Class content in class" class="img-thumbnail rounded"> </li> <li>Copy the following GetJson() Method to file Program.cs underneath the Main method. <div class="overflow-auto"> <code> private static void GetJson() { using HttpClient client = new HttpClient(); var response = client.GetAsync("https://randomuser.me/api/").Result; UserRoot? userData; var jsonString = string.Empty; if (response.IsSuccessStatusCode) { jsonString = response.Content.ReadAsStringAsync().Result; Object? k = JsonConvert.DeserializeObject<object>(jsonString); userData = JsonConvert.DeserializeObject<UserRoot>(jsonString); foreach (var item in userData.results) { Console.WriteLine($"The first and last name is {item.name.first} {item.name.last}."); Console.WriteLine($"Congratulations! You processed a JSON file."); } } else { Console.WriteLine($"No Success Status Code.\n{response.StatusCode}"); Console.ReadKey(); return; } } </code> </div> </li> <li>Put the cursor on the text JsonConvert and press Alt+Enter. <img src="/images/articles/JSON-api/13.jpeg" alt="Fix missing packages" class="img-thumbnail rounded"> </li> <li>In the context menu select Install package 'Newtonsoft.Json' > Find and install latest version. Note:The red squickly underneath JsonConvert should disappear. </li> <li>Update the Main method with the following content: <div class="overflow-auto"> <code> static void Main(string[] args) { GetJson(); Console.ReadKey(); } </code> </div> </li> <li>Press F5 to test the project. <img src="/images/articles/JSON-api/15.jpeg" alt="Application output" class="img-thumbnail rounded"> </li> </ol> This is the end of this tutorial. I hope you find this useful and wish you good luck coding your projects. <h3>Need a Freelance .NET developer?</h3> If you are in need of a freelance .NET developer, feel free to contact me by email: info {at} schoutentranslation.nl. </div> </div> </div>
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Created: 8-11-2023 12:42:14
Updated: 8-11-2023 16:46:16
Views: 4085
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