C#中，Http报文的请求怎么写？

在C#中，发送HTTP请求通常通过HttpClient类来完成，这是一个轻量级的用于HTTP通信的工具。下面是一个基本的GET请求的例子：

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

public async Task<string> GetWebRequest(string url)
{
    using (var httpClient = new HttpClient())
    {
        HttpResponseMessage response = await httpClient.GetAsync(url);
        
        // 检查请求是否成功
        if (response.IsSuccessStatusCode)
        {
            // 如果成功，读取响应内容
            string responseBody = await response.Content.ReadAsStringAsync();
            return responseBody;
        }
        else
        {
            throw new HttpRequestException($"Failed to get request. Status code: {response.StatusCode}");
        }
    }
}

如果你需要发送POST、PUT等其他类型的请求，可以修改`GetAsync`为相应的`PostAsync`、`PutAsync`等，并提供合适的请求体：

using StringContent = System.Text.StringContent;

public async Task<string> PostWebRequest(string url, string requestBody)
{
    var content = new StringContent(requestBody, Encoding.UTF8, "application/json");
    using (var httpClient = new HttpClient())
    {
        HttpResponseMessage response = await httpClient.PostAsync(url, content);

        // ...处理响应...
    }
}