我一直在尝试将 StorageFile(主要是图像文件)上传到 PHP 文件，以便它可以保存到服务器中。

ViewModel.cs

public async Task<bool> uploadFile(StorageFile file)
{
    try
    {
        using (HttpMultipartFormDataContent form = new HttpMultipartFormDataContent())
            {
                using (IInputStream fileStream = await file.OpenSequentialReadAsync())
                {
                    HttpStreamContent streamContent = new HttpStreamContent(fileStream);
                    form.Add(streamContent, "file", file.Name);

                    using (HttpClient client = new HttpClient())
                    {
                        using (HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, new Uri("localhost/uploadFile.php")))
                        {
                            request.Content = form;
                            HttpResponseMessage response =  await client.SendRequestAsync(request);
                            Debug.WriteLine("\nRequest: " + request.ToString());
                            Debug.WriteLine("\n\nResponse: " + response.ToString());
                        }
                    }
                }
            }
            return true;
   }
   catch (Exception e)
   {
       Debug.WriteLine(e.Message);
       return false;
   }
}

上传文件.php

<?php
$uploaddir = 'uploads/';
$uploadedFile = $uploaddir . basename($_FILES['file']['name']);

if (move_uploaded_file($_FILES['file']['tmp_name'], $uploadedFile)){
    echo 'File upload success!';
} else {
    echo 'Possible file upload attack!';
}
?>

问题是当我尝试上传文件时，它向我抛出一个错误 The object has been closed. (来自 HRESULT 的异常:0X80000013) 和 抛出的异常:mscorlib.ni.dll 中的“System.ObjectDisposedException”.. 我不明白，我在 中上传文件>using 语句，如何处理？我做错了什么吗？

调试向我展示了这一点

Request: Method: POST, RequestUri: 'http://localhost/uploadFile.php', Content: Windows.Web.Http.HttpMultipartFormDataContent, TransportInformation: ServerCertificate: '', ServerCertificateErrorSeverity: None, ServerCertificateErrors: {}, ServerIntermediateCertificates:{}, Headers:{ Accept-Encoding: gzip, deflate }{ Content-Length: 27749, Content-Type: multipart/form-data; boundary=9955f08b-e82d-428b-82e1-3197e5011ccd }

Response: StatusCode: 200, ReasonPhrase: 'OK', Version: 2, Content: Windows.Web.Http.HttpStreamContent, Headers:{Connection: Keep-Alive, Server: Apache/2.4.18 (Ubuntu), Keep-Alive: timeout=5, max=100, Date: Sun, 06 Nov 2016 04:02:40 GMT}{ Content-Length: 28, Content-Type: text/html; charset=UTF-8}

最佳答案

Using statement提供了一种方便的语法，可确保正确使用 IDisposable 对象。简单地说，它可以帮助你执行Dispose()。方法。所以你的代码等于:

 HttpMultipartFormDataContent form = new HttpMultipartFormDataContent();               
 IInputStream fileStream = await file.OpenSequentialReadAsync();
 HttpStreamContent streamContent = new HttpStreamContent(fileStream);
 form.Add(streamContent, "file", file.Name);    
 HttpClient client = new HttpClient();             
 HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, new Uri("http://127.0.0.1:9096/hello.php"));
 request.Content = form;      
 HttpResponseMessage response = await client.SendRequestAsync(request);
 Debug.WriteLine("\nRequest: " + request.ToString());
 Debug.WriteLine("\n\nResponse: " + response.ToString());
 request.Dispose();
 client.Dispose();
 fileStream.Dispose();
 form.Dispose();

您将在 form.Dispose(); 代码行得到异常。原因是 HttpMultipartFormDataContent.Add方法不需要处理。在我看来，它不是不需要处理的非托管资源，HttpMultipartFormDataContent 类的其他方法，如 ReadAsBufferAsync可能需要处理。

按如下方式更新您的代码，这不会引发closed 异常:

HttpMultipartFormDataContent form = new HttpMultipartFormDataContent();
using (IInputStream fileStream = await file.OpenSequentialReadAsync())
{
    HttpStreamContent streamContent = new HttpStreamContent(fileStream);
    form.Add(streamContent, "file", file.Name);

    using (HttpClient client = new HttpClient())
    {
        using (HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, new Uri("http://127.0.0.1:9096/hello.php")))
        {
            request.Content = form;
            HttpResponseMessage response = await client.SendRequestAsync(request);
            Debug.WriteLine("\nRequest: " + request.ToString());
            Debug.WriteLine("\n\nResponse: " + response.ToString());
        }
    }
}

关于c# - 将 StorageFile 上传到 PHP 文件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40439673/