如何在C#中模拟PostMan的POST请求操作

以下代码默认匹配Postman中最常用的application/json类型POST请求，若你需要发送表单、文件、自定义Header等场景，调整对应请求参数即可。

注意：不要每次请求都实例化新的HttpClient，建议使用静态单例或依赖注入框架提供的IHttpClientFactory管理实例，避免套接字资源耗尽。

using System.Net.Http;
using System.Text;
using System.Text.Json;

// 建议将httpClient声明为静态全局变量，或者通过IHttpClientFactory获取
private static readonly HttpClient httpClient = new HttpClient();

public async Task<string> PostAsync(string url, object requestBody)
{
    // 序列化请求体为JSON
    string json = JsonSerializer.Serialize(requestBody);
    StringContent content = new StringContent(json, Encoding.UTF8, "application/json");
    
    // 按需添加Header，比如Authorization、Token等和Postman中一致的配置
    // httpClient.DefaultRequestHeaders.Add("Authorization", "Bearer 你的令牌");
    
    HttpResponseMessage response = await httpClient.PostAsync(url, content);
    response.EnsureSuccessStatusCode(); // 确保响应状态码为成功区间
    return await response.Content.ReadAsStringAsync();
}

using System.Net;
using System.Text;
using System.Text.Json;

public string PostWithWebClient(string url, object requestBody)
{
    using (WebClient client = new WebClient())
    {
        // 按需添加Header
        // client.Headers.Add("Authorization", "Bearer 你的令牌");
        client.Headers.Add("Content-Type", "application/json");
        
        string json = JsonSerializer.Serialize(requestBody);
        byte[] responseBytes = client.UploadData(url, "POST", Encoding.UTF8.GetBytes(json));
        return Encoding.UTF8.GetString(responseBytes);
    }
}

使用前请先安装NuGet包：RestSharp

using RestSharp;

public string PostWithRestSharp(string url, object requestBody)
{
    var client = new RestClient(url);
    var request = new RestRequest(Method.Post);
    
    // 按需添加Header
    // request.AddHeader("Authorization", "Bearer 你的令牌");
    request.AddJsonBody(requestBody); // 自动序列化对象为JSON，设置正确的Content-Type
    
    IRestResponse response = client.Execute(request);
    if (response.IsSuccessful)
    {
        return response.Content;
    }
    throw new Exception($"请求失败：{response.ErrorMessage}");
}

内容的提问来源于stack exchange，提问作者Mark