c# WebClient

C#中的WebClient类是一个用于发送HTTP请求并接收HTTP响应的类。它可以用于下载文件、上传文件、发送POST和GET请求等。以下是WebClient类的一些用法实例：

1. 下载文件

WebClient webClient = new WebClient();
webClient.DownloadFile("http://example.com/file.txt", "file.txt");

2. 下载字符串

WebClient webClient = new WebClient();
webClient.Encoding = Encoding.UTF8; // 设置编码格式
string result = webClient.DownloadString("http://example.com");

3. 上传文件

WebClient webClient = new WebClient();
webClient.UploadFile("http://example.com/upload", "file.txt");

4. 发送POST请求

WebClient webClient = new WebClient();
webClient.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
string result = webClient.UploadString("http://example.com/post", "name=value");