windowsphone7實現檔案上傳

在基於Http協議的Post請求中，Content-type為application/x-www-form-urlencoded的傳輸只能傳送非檔案的資料。

如果想用Http的Post方法來上傳資料及檔案，需要實現Content-type為multipart/form-data類型的協議程式。

下面是參考了StackOverflow網站上的一個例子，實現了關於用戶端上傳檔案的功能類，代碼如下：

using System;using System.Net;using System.Text;using System.Collections.Generic;using System.IO;namespace ZDWorks.ZDClock.Cloud{    /// <summary>    /// 檔案類型資料的內容參數    /// </summary>    public class FileParameter    {        // 檔案內容        public byte[] File { get; set; }        // 檔案名稱        public string FileName { get; set; }        // 檔案內容類型        public string ContentType { get; set; }        public FileParameter(byte[] file) : this(file, null) { }        public FileParameter(byte[] file, string filename) : this(file, filename, null) { }        public FileParameter(byte[] file, string filename, string contentType)        {            File = file;            FileName = filename;            ContentType = contentType;        }    }    /// <summary>    /// 資料與檔案http請求    /// </summary>    public class HttpMultipartFormRequest    {        #region Data Members        private readonly Encoding DefaultEncoding = Encoding.UTF8;        private ResponseCallback m_Callback;        private byte[] m_FormData;        #endregion        #region Constructor        public HttpMultipartFormRequest()        {         }        #endregion        #region Delegate        public delegate void ResponseCallback(string msg);        #endregion        public void AsyncHttpRequest(string postUri, Dictionary<string, object> postParameters, ResponseCallback callback)        {            // 隨機序列，用作防止伺服器無法識別資料的起始位置            string formDataBoundary = String.Format("----------{0:N}", Guid.NewGuid());            // 設定contentType            string contentType = "multipart/form-data; boundary=" + formDataBoundary;            // 將資料轉換為byte[]格式            m_FormData = GetMultipartFormData(postParameters, formDataBoundary);            // 回呼函數            m_Callback = callback;            // 建立http對象            HttpWebRequest request = HttpWebRequest.CreateHttp(new Uri(postUri));            // 設為post請求            request.Method = "POST";            request.ContentType = contentType;            // 請求寫入資料流            request.BeginGetRequestStream(GetRequestStreamCallback, request);        }        private void GetRequestStreamCallback(IAsyncResult ar)        {            HttpWebRequest request = ar.AsyncState as HttpWebRequest;            using (var postStream = request.EndGetRequestStream(ar))            {                postStream.Write(m_FormData, 0, m_FormData.Length);                postStream.Close();            }            request.BeginGetResponse(GetResponseCallback, request);        }        private void GetResponseCallback(IAsyncResult ar)        {            // 處理Post請求返回的訊息            try            {                HttpWebRequest request = ar.AsyncState as HttpWebRequest;                HttpWebResponse response = request.EndGetResponse(ar) as HttpWebResponse;                using (var stream = response.GetResponseStream())                {                    StreamReader reader = new StreamReader(stream);                    string msg = reader.ReadToEnd();                    if (m_Callback != null)                    {                        m_Callback(msg);                    }                }            }            catch (Exception e)            {                string a = e.ToString();                if (m_Callback != null)                {                    m_Callback(string.Empty);                }            }        }        private byte[] GetMultipartFormData(Dictionary<string, object> postParameters, string boundary)        {            Stream formDataStream = new MemoryStream();            bool needsCLRF = false;            foreach (var param in postParameters)            {                if (needsCLRF)                {                    formDataStream.Write(DefaultEncoding.GetBytes("\r\n"), 0, DefaultEncoding.GetByteCount("\r\n"));                }                needsCLRF = true;                if (param.Value is FileParameter)                {                    FileParameter fileToUpload = (FileParameter)param.Value;                    string header = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\";\r\nContent-Type: {3}\r\n\r\n",                        boundary,                        param.Key,                        fileToUpload.FileName ?? param.Key,                        fileToUpload.ContentType ?? "application/octet-stream");                    // 將與檔案相關的header資料寫到stream中                    formDataStream.Write(DefaultEncoding.GetBytes(header), 0, DefaultEncoding.GetByteCount(header));                    // 將檔案資料直接寫到stream中                    formDataStream.Write(fileToUpload.File, 0, fileToUpload.File.Length);                }                else                {                    string postData = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}",                        boundary,                        param.Key,                        param.Value);                    formDataStream.Write(DefaultEncoding.GetBytes(postData), 0, DefaultEncoding.GetByteCount(postData));                }            }            string tailEnd = "\r\n--" + boundary + "--\r\n";            formDataStream.Write(DefaultEncoding.GetBytes(tailEnd), 0, DefaultEncoding.GetByteCount(tailEnd));            // 將Stream資料轉換為byte[]格式            formDataStream.Position = 0;            byte[] formData = new byte[formDataStream.Length];            formDataStream.Read(formData, 0, formData.Length);            formDataStream.Close();            return formData;        }    }}