C#:
基本認証を使用したHTTPリクエストの送信

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        var client = new HttpClient();
        var uri = "https://example.com/api/data";
        var username = "your_username";
        var password = "your_password";

        client.DefaultRequestHeaders.Authorization = 
            new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.ASCII.GetBytes($"{username}:{password}")));

        try
        {
            var response = await client.GetAsync(uri);
            if (response.IsSuccessStatusCode)
            {
                var content = await response.Content.ReadAsStringAsync();
                Console.WriteLine(content);
            }
            else
            {
                Console.WriteLine($"Error: {response.StatusCode}");
            }
        }
        catch(Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }
}

// Sample Output:
// {"data": "Your secure info!"}