应用程序中向web服务post文件

参数说明：
/// <param name="uploadfile">要提交的文件位置如C:\a.txt</param>
  /// <param name="url">接受文件的web地址如 http://www.yourserver.com/upload.dll</param>
  /// <param name="fileFormName">窗体名称</param>
  /// <param name="contenttype"></param>
  /// <param name="querystring">参数的一个集合</param>
  /// <param name="cookies"></param>
  /// <returns></returns>

public class UploadHelper
    {
    
        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);

            webrequest.Timeout = 1000000;

            //System.Windows.Forms.MessageBox.Show(webrequest.Timeout.ToString());

            WebResponse responce = webrequest.GetResponse();

            Stream s = responce.GetResponseStream();

            StreamReader sr = new StreamReader(s);

            string str = sr.ReadToEnd();


            fileStream.Close();

            requestStream.Close();
            
            sr.Close();

            s.Close();
            
            responce.Close();

            return str;
        }
#if debug        
        /**//// <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();
            
            // 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>


            querystring["username"]="uname";
            querystring["password"]="snake3";
            querystring["filename"]="admin.zip";

            
            string uploadfile;// set to file to upload

            uploadfile = "c:\\admin.zip";
            

            //everything except upload file and url can be left blank if needed

            string str = UploadFileEx(uploadfile,"http://10.0.0.6:8600/aisapi/UploadExtReport.dll","Filedata", "multipart/form-data",
                querystring,cookies);

            Console.Write(str);
            Console.ReadLine();

            /**//*
                *
                contents of test.php
                <?php

                print_r($_REQUEST);

                $uploadDir = '%SOMEPATH';
                $uploadFile = $uploadDir . $_FILES['userfile']['name'];
                print "<pre>";
                if (move_uploaded_file($_FILES['userfile']['tmp_name'], $uploadFile))
                {
                    print "File is valid, and was successfully uploaded. ";
                }
                else
                {
                    print "Possible file upload attack!  Here's some debugging info:\n";
                    print_r($_FILES);
                }
                print "</pre>";

                ?>*/
        }
#endif
    }

示例：

public string UploadFileEx(string strKey, string Username,string Password,string strFileName)
        {
            CookieContainer cookies = new CookieContainer();
            //add or use cookies

            NameValueCollection querystring = new NameValueCollection();
            
            // 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>
            
            
            
            querystring["username"]=Username;

            querystring["password"]=Password;
            
                        
            querystring["filename"]= strFileName;


            //everything except upload file and url can be left blank if needed

            string str = UploadHelper.UploadFileEx(strFileName,Url+"/aisapi/UploadExtReport.dll","Filedata", "multipart/form-data",
                querystring,cookies);

            return str;
        }