我被要求在C#中执行以下操作:
/**
* 1. Create a MultipartPostMethod
* 2. Construct the web URL to connect to the SDP Server
* 3. Add the filename to be attached as a parameter to the MultipartPostMethod with parameter name "filename"
* 4. Execute the MultipartPostMethod
* 5. Receive and process the response as required
* /
我写了一些没有错误的代码，但是，该文件没有附加。
有人可以看看我的 C# 代码，看看我是否写错了代码吗？
这是我的代码：
var client = new HttpClient();
const string weblinkUrl = "http://testserver.com/attach?";
var method = new MultipartFormDataContent();
const string fileName = "C:\file.txt";
var streamContent = new StreamContent(File.Open(fileName, FileMode.Open));
method.Add(streamContent, "filename");
var result = client.PostAsync(weblinkUrl, method);
MessageBox.Show(result.Result.ToString());
在C#中发布MultipartFormDataContent很简单，但第一次可能会令人困惑。这是发布. png. txt等时适用于我的代码。
// 2. Create the url
string url = "https://myurl.com/api/...";
string filename = "myFile.png";
// In my case this is the JSON that will be returned from the post
string result = "";
// 1. Create a MultipartPostMethod
// "NKdKd9Yk" is the boundary parameter
using (var formContent = new MultipartFormDataContent("NKdKd9Yk"))
{
formContent.Headers.ContentType.MediaType = "multipart/form-data";
// 3. Add the filename C:\\... + fileName is the path your file
Stream fileStream = System.IO.File.OpenRead("C:\\Users\\username\\Pictures\\" + fileName);
formContent.Add(new StreamContent(fileStream), fileName, fileName);
using (var client = new HttpClient())
{
// Bearer Token header if needed
client.DefaultRequestHeaders.Add("Authorization", "Bearer " + _bearerToken);
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("multipart/form-data"));
try
{
// 4.. Execute the MultipartPostMethod
var message = await client.PostAsync(url, formContent);
// 5.a Receive the response
result = await message.Content.ReadAsStringAsync();
}
catch (Exception ex)
{
// Do what you want if it fails.
throw ex;
}
}
}
// 5.b Process the reponse Get a usable object from the JSON that is returned
MyObject myObject = JsonConvert.DeserializeObject<MyObject>(result);
在我的情况下，我需要在对象发布后对其执行一些操作，因此我使用JsonConversion将其转换为该对象。
我调试了这个问题在这里：
method.Add(streamContent, "filename");
这个“添加”实际上并没有将文件放在多部分内容的主体中。
我知道这是一个老帖子，但对于那些寻找解决方案的人来说，为了提供一个更直接的答案，这里是我的发现:
using System.Diagnostics;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;
public class UploadController : ApiController
{
public async Task<HttpResponseMessage> PostFormData()
{
// Check if the request contains multipart/form-data.
if (!Request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
string root = HttpContext.Current.Server.MapPath("~/App_Data");
var provider = new MultipartFormDataStreamProvider(root);
try
{
// Read the form data.
await Request.Content.ReadAsMultipartAsync(provider);
// This illustrates how to get the file names.
foreach (MultipartFileData file in provider.FileData)
{
Trace.WriteLine(file.Headers.ContentDisposition.FileName);
Trace.WriteLine("Server file path: " + file.LocalFileName);
}
return Request.CreateResponse(HttpStatusCode.OK);
}
catch (System.Exception e)
{
return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, e);
}
}
}
这是我找到它的地方：http://www.asp.net/web-api/overview/advanced/sending-html-form-data，第二部分
要获得更详细的实施：http://galratner.com/blogs/net/archive/2013/03/22/using-html-5-and-the-web-api-for-ajax-file-uploads-with-image-preview-and-a-progress-bar.aspx
