Http entities in C#

To encode HTML special characters in C#, you can use the System.Net.WebUtility.HtmlEncode() method. This method takes a string input and returns a string where all HTML special characters are encoded. Here's an example:

string originalString = "<h1>Hello, world!</h1>";
string encodedString = System.Net.WebUtility.HtmlEncode(originalString);
Console.WriteLine(encodedString);

Output:

&lt;h1&gt;Hello, world!&lt;/h1&gt;

To decode HTML special characters in C#, you can use the System.Net.WebUtility.HtmlDecode() method. This method takes a string input and returns a string where all encoded HTML special characters are decoded. Here's an example:

string encodedString = "&lt;h1&gt;Hello, world!&lt;/h1&gt;";
string decodedString = System.Net.WebUtility.HtmlDecode(encodedString);
Console.WriteLine(decodedString);

Output:

<h1>Hello, world!</h1>

HttpRequestMessage class C#:
- Introduction to the HttpRequestMessage class for constructing HTTP requests.
- Code snippet:
```
var request = new HttpRequestMessage(HttpMethod.Get, "https://api.example.com");
```
HttpResponseMessage class C#:
- Introduction to the HttpResponseMessage class representing an HTTP response.
- Code snippet:
```
var response = new HttpResponseMessage(HttpStatusCode.OK);
```
Working with HTTP headers in C#:
- Overview of manipulating HTTP headers in requests and responses.
- Code snippet:
```
request.Headers.Add("User-Agent", "MyApp");
```
HTTP content types in C#:
- Explanation of specifying content types in HTTP messages.
- Code snippet:
```
request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
```

C# HTTP request parameters:

Overview of including parameters in an HTTP request.

Code snippet:

var parameters = new Dictionary<string, string>
{
    { "key1", "value1" },
    { "key2", "value2" }
};
var queryString = new FormUrlEncodedContent(parameters);

HTTP status codes in C#:
- Explanation of HTTP status codes in responses.
- Code snippet:
```
response.StatusCode = HttpStatusCode.NotFound;
```

Handling cookies in C# HTTP requests:

Explanation of working with cookies in HTTP requests.

Code snippet:

var cookieContainer = new CookieContainer();
using (var handler = new HttpClientHandler() { CookieContainer = cookieContainer })
using (var client = new HttpClient(handler))
{
    // Make requests
}

C# HTTP response headers:
- Extracting and working with headers from an HTTP response.
- Code snippet:
```
var contentType = response.Content.Headers.ContentType;
```
C# HTTP request methods:
- Explanation of various HTTP request methods (GET, POST, etc.).
- Code snippet:
```
var request = new HttpRequestMessage(HttpMethod.Post, "https://api.example.com");
```
HTTP request encoding in C#:
- Overview of encoding in HTTP requests.
- Code snippet:
```
request.Content.Headers.ContentEncoding.Add("gzip");
```
C# HTTP response stream handling:
- Handling the response stream from an HTTP request.
- Code snippet:
```
using (var stream = await response.Content.ReadAsStreamAsync())
{
    // Process the stream
}
```