以编程方式将文件从客户端上传到服务器

Question

我正在使用一个简单的应用程序进行文件上传控制，该应用程序自动将文件传输到服务器。

我将这些示例 Setting a file to upload inside the WebBrowser component 和 UploadFileEx 用作参考，但测试时不会在服务器上创建文件！

表格代码：

// simulate this form 
        //<form action ="http://localhost/test.php" method = POST>
        //<input type = text name = uname>
        //<input type = password name =passwd>
        //<input type = FILE name = uploadfile>
        //<input type=submit>

我发现这个类使用 HttpWebRequest 将文件发布到服务器：

    public static string UploadFileEx(  string uploadfile, string url,
        string fileFormName, string contenttype,NameValueCollection querystring,
        CookieContainer cookies)
    {
        if( (fileFormName== null) ||
            (fileFormName.Length ==0))
        {
            fileFormName = "file";
        }

        if( (contenttype== null) ||
            (contenttype.Length ==0))
        {
            contenttype = "application/octet-stream";
        }


        string postdata;
        postdata = "?";
        if (querystring!=null)
        {
            foreach(string key in querystring.Keys)
            {
                postdata+= key +"=" + querystring.Get(key)+"&";
            }
        }
        Uri uri = new Uri(url+postdata);


        string boundary = "----------" + DateTime.Now.Ticks.ToString("x");
        HttpWebRequest webrequest = (HttpWebRequest)WebRequest.Create(uri);
        webrequest.CookieContainer = cookies;
        webrequest.ContentType = "multipart/form-data; boundary=" + boundary;
        webrequest.Method = "POST";


        // Build up the post message header
        StringBuilder sb = new StringBuilder();
        sb.Append("--");
        sb.Append(boundary);
        sb.Append("\r\n");
        sb.Append("Content-Disposition: form-data; name=\"");
        sb.Append(fileFormName);
        sb.Append("\"; filename=\"");
        sb.Append(Path.GetFileName(uploadfile));
        sb.Append("\"");
        sb.Append("\r\n");
        sb.Append("Content-Type: ");
        sb.Append(contenttype);
        sb.Append("\r\n");
        sb.Append("\r\n");          

        string postHeader = sb.ToString();
        byte[] postHeaderBytes = Encoding.UTF8.GetBytes(postHeader);

        // Build the trailing boundary string as a byte array
        // ensuring the boundary appears on a line by itself
        byte[] boundaryBytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

        FileStream fileStream = new FileStream(uploadfile, FileMode.Open, FileAccess.Read);
        long length = postHeaderBytes.Length + fileStream.Length + boundaryBytes.Length;
        webrequest.ContentLength = length;

        Stream requestStream = webrequest.GetRequestStream();

        // Write out our post header
        requestStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);

        // Write out the file contents
        byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)fileStream.Length))];
        int bytesRead = 0;
        while ( (bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0 )
            requestStream.Write(buffer, 0, bytesRead);

        // Write out the trailing boundary
        requestStream.Write(boundaryBytes, 0, boundaryBytes.Length);
        requestStream.Flush();
        requestStream.Close();
        WebResponse responce = webrequest.GetResponse();
        Stream s = responce.GetResponseStream();
        StreamReader sr = new StreamReader(s);

        return sr.ReadToEnd();

    }
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main(string[] args)
    {
        CookieContainer cookies = new CookieContainer();
        //add or use cookies

        NameValueCollection querystring = new NameValueCollection();

        querystring["uname"]="";
        querystring["passwd"]="";

        string uploadfile;// set to file to upload

        uploadfile = "C:\\test.jpg";

        UploadFileEx(uploadfile, "http://127.0.0.1/app/Default.aspx", "uploadfile", "image/pjpeg",
                        querystring, cookies);



    }

在我的情况下，我想通过 WebBrowser 控件使用这个类，但是当我将帖子发送到服务器时，文件（test.jpg）没有创建！

可能是文件夹权限问题！但是当使用 IIS 进行本地测试时，我遇到了同样的问题？

谢谢

Answer 1

您的问题有点难以理解，如果这不是正确的答案，很抱歉，但如果您想使用带有标准 POST 的 WebRequest 上传文件，则如下所示：Upload files with HTTPWebrequest (multipart/form-data)