System.Net Namespace

Provides classes for network programming. This namespace includes classes for working with IP addresses, sockets, and HTTP requests.

Classes

  • IPAddress

    Represents an Internet Protocol (IP) address.

  • Dns

    Provides a simple way to query Domain Name System (DNS) records.

  • Socket

    Provides the Windows Sockets API functionality.

  • HttpClient

    Sends an HTTP request, as an asynchronous operation, and receives an HTTP response from the resource identified by the URI.

  • NetworkInformation

    Provides classes for retrieving network configuration and statistics.

  • Uri

    Represents a Uniform Resource Identifier (URI) reference.

  • WebRequest

    A base class that provides a common interface for network requests.

  • WebResponse

    A base class that provides a common interface for network responses.

  • IPEndPoint

    Represents a network endpoint as an IP address and a port number.

Interfaces

  • ICredentials

    Defines methods and properties that enable an object to provide credentials for network authentication.

  • ICredentialsCollection

    Represents a collection of network credentials.

  • IServerHello

    Represents the ServerHello message in an SSL/TLS handshake.

Enumerations

  • SecurityProtocolType

    Specifies the protocols that are allowed for transport layer security (TLS) and secure sockets layer (SSL) communications.

  • SocketsFlags

    Specifies socket options.

  • IPVersions

    Specifies the IP version.

Common Scenarios

The System.Net namespace is fundamental for building applications that communicate over a network. Some common scenarios include:

  • Performing HTTP requests to fetch web content using HttpClient or WebRequest.
  • Resolving domain names to IP addresses using the Dns class.
  • Working with IP addresses and network endpoints using IPAddress and IPEndPoint.
  • Creating and managing socket connections for low-level network communication.

Example: Fetching a Web Page


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

public class WebFetcher
{
    public static async Task Main(string[] args)
    {
        using (HttpClient client = new HttpClient())
        {
            try
            {
                string url = "https://www.example.com";
                HttpResponseMessage response = await client.GetAsync(url);
                response.EnsureSuccessStatusCode(); // Throw if the status is not success

                string responseBody = await response.Content.ReadAsStringAsync();
                Console.WriteLine($"Successfully fetched content from {url}:");
                Console.WriteLine(responseBody.Substring(0, Math.Min(responseBody.Length, 500)) + "..."); // Display first 500 chars
            }
            catch (HttpRequestException e)
            {
                Console.WriteLine($"Request error: {e.Message}");
            }
            catch (Exception e)
            {
                Console.WriteLine($"An unexpected error occurred: {e.Message}");
            }
        }
    }
}

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