In this article, I'll show you how to use feature Add->REST API Client in Visual Studio 2017. To practice demo, you should read How to implement swagger ui with web api in asp.net mvc, then create a new windows forms project and design your ui as shown below.

c# web api winforms

Right click on your project->Add->REST API Client..., enter your URL to use Swagger to generate the REST API client.

add rest api client in visual studio

Swagger is an agile technology standard that enables the discovery of REST APIs, providing a way for any software to determine the features of a REST API.

add rest api client in visual studio 2017

Click OK button to generate your api client

c# web api

You can see your api client automatically generate in your project

Add code to handler load button event

private void btnLoad_Click(object sender, EventArgs e)
{
    TestServiceClient client = new TestServiceClient(new Uri("http://localhost:49814"), new AnonymousCredential());

    //var headers = client.HttpClient.DefaultRequestHeaders;
    //string accessToken = "";
    //headers.Remove("Authorization");
    //headers.Add("Authorization", $"Bearer {accessToken}");

    CustomerOperations operations = new CustomerOperations(client);
    customerBindingSource.DataSource = operations.GetCustomers();
}

Create an AnonymousCredential class inheriting from ServiceClientCredentials

public class AnonymousCredential : ServiceClientCredentials
{

}

Press F5 to run your project

c# web api client