小编Ham*_*mid的帖子

我正在编写一个web api,它有一个post方法接受从UI上传的文件.

public async Task<List<string>> PostAsync()
    {

        if (Request.Content.IsMimeMultipartContent("form-data"))
        {
            string uploadPath = HttpContext.Current.Server.MapPath("~/uploads");

            var streamProvider = new MyStreamProvider(uploadPath);

            await Request.Content.ReadAsMultipartAsync(streamProvider);

            return streamProvider.FileData
                .Select(file => new FileInfo(file.LocalFileName))
                .Select(fi => "File uploaded as " + fi.FullName + " (" + fi.Length + " bytes)")
                .ToList();
        }
        else
        {
            HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.BadRequest, "Invalid Request!");
            throw new HttpResponseException(response);
        }
    }

然后我邮递员要求上述行动.我将content-type标头设置为multipart/form-data,但在执行操作期间发生错误.这是错误信息正文:

"提供了无效的'HttpContent'实例.它没有带'border'参数的'multipart'内容类型标头.\ r \nParameter name:content"

我去了邮差标题,但我发现请求标题内容类型in设置为application-json.

谁能帮我？

将Microsoft.Aspnet.Webapi.Webhost包安装到我的web api项目后,我最终得到以下异常:

无法加载文件或程序集'System.Web.Http,Version = 5.0.0.0,Culture = neutral,PublicKeyToken = 31bf3856ad364e35'或其依赖项之一.定位的程序集的清单定义与程序集引用不匹配.(HRESULT异常:0x80131040)

我遇到Web Api 2的问题.我在ContactGroupsController web api中编写了这3个动作.

// POST api/contactgroups
[System.Web.Http.HttpPost]
public IEnumerable<ContactsGroup> All()
{
    return _biz.GetAllContactsGroup();
}




// POST api/contactgroups/5
[System.Web.Http.HttpPost]
public ContactsGroup FindById(int id)
{
    return _biz.GetContactGroup(id);
}




// POST api/contactgroups
public HttpResponseMessage CreateContactGroup(ContactsGroup item)
{
    item.UserId = HttpContext.Current.User.Identity.GetUserId();
    item.DateAdded = DateTime.Now;

    if (!ModelState.IsValid)
        return Request.CreateResponse(HttpStatusCode.NotAcceptable, item);

    if (!_biz.CreateContactGroup(item)) return Request.CreateResponse(HttpStatusCode.NotFound, item);

    HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, item);
    response.Headers.Location = new Uri(Request.RequestUri + item.Id.ToString());
    return response;
}

当我想将http post方法发送到"/ api/contactgroups"时,会出现以下错误:

  {
    "$id": "1",
    "Message": "An error has occurred.",
    "ExceptionMessage": "Multiple actions …