Asp.net 3.5 - PostBack,FileUpload et serialisation

Après chaque postback le contenu du composant FileUpload est perdu si  on ne l’exploite pas. Il peut arriver des cas où l’on a besoin de le conserver sans forcément le sauvegarder sur disque.

Pour ces situations, j’utilise un objet SessionHttpPostedFile, reprenant les même possiblités qu’un HttpPostedFile et que j’ai rendu sérializable.

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.IO;

 

/// <summary>

/// Equivalent Serializable d'un httpPostedFile, permet entre autre son stockage en session

/// </summary>

[Serializable]

public class SessionHttpPostedFile

{

 

    private byte[] BytePostedFile;

    [NonSerialized]

    private Stream TmpStream;

 

    /// <summary>

    /// Constructeur

    /// </summary>

    public SessionHttpPostedFile()

    {

        TmpStream = new MemoryStream();

        ContentLength = 0;

        ContentType = string.Empty;

        FileName = string.Empty;

    }

 

    /// <summary>

    /// Taille du fichier en Byte

    /// </summary>

    public int ContentLength { get; set; }

   

    /// <summary>

    /// Type Mime du fichier

    /// </summary>

    public string ContentType { get; set; }

 

    /// <summary>

    /// Nom du fichier

    /// </summary>

    public string FileName { get; set; }

   

    /// <summary>

    /// InputStream du fichier

    /// </summary>

    public Stream InputStream

    {

        get

        {

 

            if ((TmpStream == null || TmpStream.Length < 1) && BytePostedFile != null)

            {

                TmpStream = new MemoryStream();

                TmpStream.Write(BytePostedFile, 0, BytePostedFile.Length);

            }

            return TmpStream;

        }

        set {

            TmpStream = value;

            BytePostedFile = ReadToEnd(TmpStream);

        }

    }

 

    /// <summary>

    /// Sauvegarde le stream à l'emplacement voulu

    /// </summary>

    /// <param name="SaveFilename"></param>

    public void SaveAs(string SaveFilename)

    {

        try

        {

            var f = File.Create(SaveFilename);

            f.Close();

            File.WriteAllBytes(SaveFilename, BytePostedFile);

        }

        catch { }

 

      

    }

 

 

 

    /// <summary>

    /// Converti un stream en Byte[]

    /// </summary>

    /// <param name="stream"></param>

    /// <returns></returns>

    private  byte[] ReadToEnd(System.IO.Stream stream)

    {

        long originalPosition = stream.Position;

        stream.Position = 0;

        try

        {

            byte[] readBuffer = new byte[4096];

            int totalBytesRead = 0; int bytesRead;

            while ((bytesRead = stream.Read(readBuffer, totalBytesRead, readBuffer.Length - totalBytesRead)) > 0)

            {

                totalBytesRead += bytesRead;

                if (totalBytesRead == readBuffer.Length)

                {

                    int nextByte = stream.ReadByte();

                    if (nextByte != -1)

                    {

                        byte[] temp = new byte[readBuffer.Length * 2];

                        Buffer.BlockCopy(readBuffer, 0, temp, 0, readBuffer.Length);

                        Buffer.SetByte(temp, totalBytesRead, (byte)nextByte);

                        readBuffer = temp; totalBytesRead++;

                    }

                }

            }

            byte[] buffer = readBuffer; if (readBuffer.Length != totalBytesRead) { buffer = new byte[totalBytesRead]; Buffer.BlockCopy(readBuffer, 0, buffer, 0, totalBytesRead); } return buffer;

        }

        finally { stream.Position = originalPosition; }

    }

}