C# 接口案例

1、代码中实现类似前端直接传文件以及其他参数的案例：

  dynamic 参数实体 = new ExpandoObject();  
参数实体.aa="";
using var formData = new MultipartFormDataContent();
  var httpContent = new StringContent(JsonConvert.SerializeObject(参数实体), Encoding.UTF8, "application/json");
  formData.Add(httpContent, "param");
  var fileStream = File.OpenRead(文件绝对路径);
  var fileContent = new StreamContent(fileStream);
//表明参数格式
  fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("application/octet-stream");
  formData.Add(fileContent, "file", Path.GetFileName(文件绝对路径));
 var httpClient = new HttpClient();
//调用接口
 var response = await httpClient.PostAsync(接口地址, formData);
 if (response.IsSuccessStatusCode){
  var responseBody = await response.Content.ReadAsStringAsync();  //响应
}