using System;
using System.Collections.Generic;
using System.IO;
using MongoDB.Driver;
using MongoDB.Driver.GridFS;

/// <summary>
///MongoFileManger 的摘要说明
/// </summary>
public class MongoFileManger
{
    #region Fields

    private MongoDatabase _database;

    #endregion

    #region Properties

    public string ConnectionString { get; private set; }
    public string DatabaseName { get; private set; }

    #endregion

    #region Constructors

    /// <summary>
    /// Constructor
    /// </summary>
    public MongoFileManger()
        : this("mongodb://localhost/?safe=true", "test")
    {
    }

    /// <summary>
    /// Constructor
    /// </summary>
    /// <param name="connectionString"></param>
    /// <param name="databaseName"></param>
    public MongoFileManger(string connectionString, string databaseName)
    {
        ConnectionString = connectionString;
        DatabaseName = databaseName;
        _database = (MongoServer.Create(ConnectionString)).GetDatabase(DatabaseName);
    }

    #endregion

    #region Methods

    /// <summary>
    /// Write
    /// </summary>
    /// <param name="path"></param>
    /// <returns></returns>
    public string Write(string path)
    {
        string filename = Guid.NewGuid().ToString();
        MongoGridFS gridfs = new MongoGridFS(_database);        
        byte[] bytes = new byte[1024];
        int length = 0;
        using (MongoGridFSStream stream = gridfs.Open(filename, FileMode.Create))
        {
            using (FileStream fileStream = File.Open(path, FileMode.Open))
            {
                while ((length = fileStream.Read(bytes, 0, bytes.Length)) > 0)
                {
                    stream.Write(bytes, 0, length);
                }
            }
        }
        return filename;
    }

    /// <summary>
    /// Write
    /// </summary>
    /// <param name="bytes"></param>
    /// <returns></returns>
    public string Write(byte[] bytes)
    {
        string filename = Guid.NewGuid().ToString();
        MongoGridFS gridfs = new MongoGridFS(_database);
        using (MongoGridFSStream stream = gridfs.Open(filename, FileMode.Create))
        {
            stream.Write(bytes, 0, bytes.Length);
        }
        return filename;
    }

    /// <summary>
    /// Read
    /// </summary>
    /// <param name="filename"></param>
    /// <returns></returns>
    public byte[] Read(string filename)
    {
        MongoGridFS gridfs = new MongoGridFS(_database);
        byte[] bytes;
        using (MongoGridFSStream stream = gridfs.Open(filename, FileMode.Open))
        {
            bytes = new byte[stream.Length];
            stream.Read(bytes, 0, bytes.Length);
        }
        return bytes;
    }

    /// <summary>
    /// Delete
    /// </summary>
    /// <param name="filename"></param>
    public void Delete(string filename)
    {
        MongoGridFS gridfs = new MongoGridFS(_database);
        gridfs.Delete(filename);
    }

    /// <summary>
    /// FindAll
    /// </summary>
    /// <returns></returns>
    public List<string> FindAll()
    {
        List<string> result = new List<string>();
        MongoGridFS gridfs = new MongoGridFS(_database);
        MongoCursor<MongoGridFSFileInfo> files = gridfs.FindAll();
        foreach (MongoGridFSFileInfo item in files)
            result.Add(item.Name);
        return result;
    }

    #endregion
}

<%@ WebHandler Language="C#" Class="Default" %>

using System;
using System.Web;
using System.Collections.Generic;

public class Default : IHttpHandler {
    public void ProcessRequest (HttpContext context) {        
        //context.Response.ContentType = "text/plain";
        MongoFileManger file = new MongoFileManger();
        string filename = file.Write(@"E:\Demo\WebSite1\test.gif");
        byte[] bytes = file.Read(filename);
        context.Response.BinaryWrite(bytes);

        //MongoFileManger manager = new MongoFileManger();
        //List<string> files = manager.FindAll();
        //foreach (string item in files)
        //    context.Response.Write(item + "<br/>");
    }

    public bool IsReusable {
        get {
            return false;
        }
    }
}