Strange error

[PT Exorcist]

hmmm i am getting a g@y error...i have 2events who share the same delegate..the param of the delegate and events is the class itself so it sends the class as param...hmm but only 1event is working!!! i cant understand why
(the thing that isn't working is in comment, it's the connectionStateChanged)

using System;

namespace downloadClass
{
    using System;
    using System.Net;
    using System.Threading;

    public class downloadManager
    {
        #region Vars
        private string    _downloadAddress;
        private string    _downloadFolder;
        private double    _currentProgress = -1;
        private long    _fileSize = -1;
        private int        _downloaded = -1;
        private ConnectionState _connectionState = 0;

        /// <summary>
        /// Delegate used by this class
        /// </summary>
        public delegate void downloadHandle(downloadManager e);

        /// <summary>
        /// Ocorrs everytime the download progress is changed
        /// </summary>
        public event downloadHandle progressChanged;
        /// <summary>
        /// Returns the connection state within the connectionState enumerator
        /// </summary>
        public event downloadHandle connectionStateChanged;

        /// <summary>
        /// An enumeration with the possible connection states
        /// </summary>
        public enum ConnectionState
        {
            Disconnected,
            Connecting,
            Connected,
            Downloading,
            Error,
            DownloadComplete
        }

        /// <summary>
        /// The download url from where to download
        /// </summary>
        public string downloadAddress
        {
            get
            {
                return _downloadAddress;
            }
            set
            {
                _downloadAddress = value;
            }
        }

        /// <summary>
        /// The download path
        /// </summary>
        public string downloadFolder
        {
            get
            {
                return _downloadFolder;
            }
            set
            {
                _downloadFolder = value;
            }
        }


        /// <summary>
        /// The current progress of the download
        /// <returns>If the download still hasn't began then this method will return -1</returns>
        /// </summary>
        public double currentProgress
        {
            get
            {
                return _currentProgress;
            }
        }

        /// <summary>
        /// The percentage of download
        /// <returns>Returns the size in kb and returns -1 if the download still hasn't began</returns>
        /// </summary>
        public long fileSize
        {
            get
            {
                return _fileSize;
            }
        }

        /// <summary>
        /// Returns the file size of the already downloaded file
        /// </summary>
        public int downloaded
        {
            get
            {
                return _downloaded;
            }
        }

        public ConnectionState connectionState
        {
            get
            {
                return _connectionState;
            }
        }

        #endregion

        #region Constructors
        public downloadManager()
        {
        }

        public downloadManager(string url, string path)
        {
            this._downloadFolder = path;
            this._downloadAddress = url;
        }
        #endregion
        
        /// <summary>
        /// Downloads a file to the hard drive
        /// </summary>
        public void downloadFile()
        {
            Thread thread = new Thread(new System.Threading.ThreadStart(t_downloadFile));
            thread.Name = this._downloadAddress;
            thread.Start();
        }

        /// <summary>
        /// Checks if a url has a known size
        /// </summary>
        public bool urlHasKnownSize()
        {
                #region Check Up
            if (!(this._downloadAddress.StartsWith("http://") || this._downloadAddress.StartsWith("www.")))
            {
                throw (new System.Net.ProtocolViolationException("The provided url is not valid (" + this._downloadAddress + ")"));
            }
                #endregion

            HttpWebRequest wr = ((HttpWebRequest)WebRequest.Create(this._downloadAddress));
            HttpWebResponse res = ((HttpWebResponse)wr.GetResponse());

            if (res.ContentLength == -1)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        private void t_downloadFile()
        {
            #region Check Up's
            if (!(this._downloadAddress.StartsWith("http://") || this._downloadAddress.StartsWith("www.")))
            {
                throw (new System.Net.ProtocolViolationException("The provided url is not valid (" + this._downloadAddress + ")"));
            }

            int pathPos = this._downloadFolder.LastIndexOf(@"\");
            string path = this._downloadFolder.Substring(0, pathPos) + @"\";

            if (!(System.IO.Directory.Exists(path)))
            {
                throw (new System.IO.DirectoryNotFoundException("The provided path could not be found (" + this._downloadAddress + ")"));
            }
            #endregion

            HttpWebRequest wr = ((HttpWebRequest)WebRequest.Create(this._downloadAddress));
            HttpWebResponse res = ((HttpWebResponse)wr.GetResponse());
                
            this._connectionState = ConnectionState.Connecting;
            this._fileSize = res.ContentLength;
            //            this.connectionStateChanged(this);
            //            this.connectionStateChanged(this);

            System.IO.Stream streamIn = res.GetResponseStream();
            System.IO.FileStream streamOut = 
                new System.IO.FileStream(this._downloadFolder, System.IO.FileMode.Create);

            const int BUFFER_SIZE = 4096;
            byte[] buffer = new byte[BUFFER_SIZE];
            int iRead = streamIn.Read(buffer, 0, BUFFER_SIZE);
            int mRead = iRead;

            this._connectionState = ConnectionState.Connected;
            //            this.connectionStateChanged(this);

            while (iRead > 0)
            {
                streamOut.Write(buffer, 0, iRead);
                iRead = streamIn.Read(buffer, 0, 4096);
                mRead += iRead;
                this._downloaded = mRead;
                this._currentProgress = (double)mRead / (double)res.ContentLength * (double)100;
                this.progressChanged(this);
            }

            this._connectionState = ConnectionState.DownloadComplete;
            this.progressChanged(this);

            streamIn.Close();
            streamOut.Close();
        }
    }

} 

[PT Exorcist]

anybody? i just can't understand why 1event is raising error and the other one isn't..

[pvb]

I think you need to make sure those events are hooked up in the client and then before calling an event ya need to check to make sure it's hooked up:

//Make sure it's hooked up before calling it.
if (YourEvent != null)
  YourEvent(this); 

Out of curiousity i threw together a cut down version of your sample:

using System;
using System.Net;
using System.Web;
using System.IO;

namespace DownloadUtility
{
    public class DownloadManager
    {
        private string url;
        private string fileName;
        private string localFolder;
        private ConnectionState connectionState;
        private long fileSize;
        public delegate void StateChangeHandler(DownloadManager dm);
        public event StateChangeHandler OnConnectionStateChange;
        public event StateChangeHandler OnProgressChange;

        public enum ConnectionState
        {
            Closed = 0,
            Connecting,
            Connected,
            Downloading
        }
        
        public long FileSize
        {
            get { return fileSize; }
        }

        public ConnectionState State
        {
            get { return connectionState; }
        }

        public string Url
        {
            get { return url; }
            set { url = value; }
        }
        
        public string FileName
        {
            get { return fileName; }
            set { fileName = value; }
        }

        public string LocalFolder
        {
            get { return localFolder; }
            set { localFolder = value; }
        }

        public DownloadManager()
        {
            connectionState = ConnectionState.Closed;
            if(OnConnectionStateChange != null)
                OnConnectionStateChange(this);
        }

        public DownloadManager(string Url, string FileName, string LocalFolder)
        {
            this.url = Url;
            this.localFolder = LocalFolder;
            this.fileName = FileName;
            connectionState = ConnectionState.Closed;
            if (OnConnectionStateChange != null)
                OnConnectionStateChange(this);
        }

        public void Download()
        {
            this.connectionState = ConnectionState.Connecting;
            if (OnConnectionStateChange != null)
                OnConnectionStateChange(this);

            HttpWebRequest req = ((HttpWebRequest)WebRequest.Create(this.url+this.fileName));

            this.connectionState = ConnectionState.Connected;
            if (OnConnectionStateChange != null)
                OnConnectionStateChange(this);

            HttpWebResponse resp = ((HttpWebResponse)req.GetResponse());

            this.connectionState = ConnectionState.Downloading;
            if (OnConnectionStateChange != null)
                OnConnectionStateChange(this);

            this.fileSize = resp.ContentLength;
            Stream streamIn = resp.GetResponseStream();
            FileStream streamOut = new FileStream(this.localFolder+this.fileName,FileMode.Create);
            const int BUFFER_SIZE = 4096;
            byte[] buffer = new byte[BUFFER_SIZE];
            int iRead = streamIn.Read(buffer, 0, BUFFER_SIZE);            
            while (iRead > 0)
            {
                if (OnProgressChange != null)
                    OnProgressChange(this);
                streamOut.Write(buffer, 0, iRead);
                iRead = streamIn.Read(buffer, 0, 4096);            
            }
            streamIn.Close();
            streamOut.Close();
            resp.Close();
            this.connectionState = ConnectionState.Closed;
            if (OnConnectionStateChange != null)
                OnConnectionStateChange(this);
        }


    }
} 

And the client code looks like this:

namespace DelegateTest
{
    public class MainApp
    {
        public static void Main(string[] args)
        {
            DownloadManager dm = new DownloadManager();
            dm.OnConnectionStateChange += 
                new DownloadManager.StateChangeHandler(ConnectionStateChanged);
            dm.OnProgressChange +=
                new DownloadManager.StateChangeHandler(ProgressChanged);
            dm.FileName = "default.aspx";
            dm.LocalFolder = @"D:\XmlData\";
            dm.Url = @"http://www.panteravb.com/panteravb/";
            dm.Download();
            
            Console.WriteLine("Press <Enter> to exit ...");
            Console.ReadLine();
        }
        public static void ConnectionStateChanged(DownloadManager dm)
        {
            Console.WriteLine("Connection is now: {0}", dm.State.ToString());
        }
        public static void ProgressChanged(DownloadManager dm)
        {
            Console.WriteLine("Progress fired!");
        }
    }
} 

[PT Exorcist]

still the same error =\

[PT Exorcist]

i think the problem is that i'm sending an instance of the class using this:

<myEvent>(this);

[pvb]

nah, that's what my code does, in fact most events do. Maybe post your client code and if ya changed anything in your code post that too.

[pvb]

ok, i only added a couple of things to your original code to make it work, i've commented those items, they are all in the t_downloadFile() method:

using System;
using System.Threading;
using downloadClass;

namespace DelegateTest
{
    public class MainApp
    {
        public static void Main(string[] args)
        {
            downloadManager dm = new downloadManager();
            dm.connectionStateChanged += 
                new downloadManager.downloadHandle(ConnStateChanged);
            dm.progressChanged +=
                new downloadManager.downloadHandle(ProgChanged);
            dm.downloadFolder = @"D:\XmlData\test.aspx";
            dm.downloadAddress = @"http://www.panteravb.com/panteravb/default.aspx";
            dm.downloadFile();
            Console.WriteLine("Press <Enter> to exit ...");
            Console.ReadLine();
        }
        public static void ConnStateChanged(downloadManager dm)
        {
            Console.WriteLine("State changed to {0}", dm.connectionState.ToString());
        }
        public static void ProgChanged(downloadManager dm)
        {
            Console.WriteLine("We're makin progress!!");
        }
    }

}

namespace downloadClass
{
    using System;
    using System.Net;
    using System.Threading;

    public class downloadManager
    {
        #region Vars
        private string    _downloadAddress;
        private string    _downloadFolder;
        private double    _currentProgress = -1;
        private long    _fileSize = -1;
        private int        _downloaded = -1;
        private ConnectionState _connectionState = 0;

        /// <summary>
        /// Delegate used by this class
        /// </summary>
        public delegate void downloadHandle(downloadManager e);

        /// <summary>
        /// Ocorrs everytime the download progress is changed
        /// </summary>
        public event downloadHandle progressChanged;
        /// <summary>
        /// Returns the connection state within the connectionState enumerator
        /// </summary>
        public event downloadHandle connectionStateChanged;

        /// <summary>
        /// An enumeration with the possible connection states
        /// </summary>
        public enum ConnectionState
        {
            Disconnected,
            Connecting,
            Connected,
            Downloading,
            Error,
            DownloadComplete
        }

        /// <summary>
        /// The download url from where to download
        /// </summary>
        public string downloadAddress
        {
            get
            {
                return _downloadAddress;
            }
            set
            {
                _downloadAddress = value;
            }
        }

        /// <summary>
        /// The download path
        /// </summary>
        public string downloadFolder
        {
            get
            {
                return _downloadFolder;
            }
            set
            {
                _downloadFolder = value;
            }
        }


        /// <summary>
        /// The current progress of the download
        /// <returns>If the download still hasn't began then this method will return -1</returns>
        /// </summary>
        public double currentProgress
        {
            get
            {
                return _currentProgress;
            }
        }

        /// <summary>
        /// The percentage of download
        /// <returns>Returns the size in kb and returns -1 if the download still hasn't began</returns>
        /// </summary>
        public long fileSize
        {
            get
            {
                return _fileSize;
            }
        }

        /// <summary>
        /// Returns the file size of the already downloaded file
        /// </summary>
        public int downloaded
        {
            get
            {
                return _downloaded;
            }
        }

        public ConnectionState connectionState
        {
            get
            {
                return _connectionState;
            }
        }

        #endregion

        #region Constructors
        public downloadManager()
        {
        }

        public downloadManager(string url, string path)
        {
            this._downloadFolder = path;
            this._downloadAddress = url;
        }
        #endregion
        
        /// <summary>
        /// Downloads a file to the hard drive
        /// </summary>
        public void downloadFile()
        {
            Thread thread = new Thread(new System.Threading.ThreadStart(t_downloadFile));
            thread.Name = this._downloadAddress;
            thread.Start();
        }

        /// <summary>
        /// Checks if a url has a known size
        /// </summary>
        public bool urlHasKnownSize()
        {
                #region Check Up
            if (!(this._downloadAddress.StartsWith("http://") || this._downloadAddress.StartsWith("www.")))
            {
                throw (new System.Net.ProtocolViolationException("The provided url is not valid (" + this._downloadAddress + ")"));
            }
                #endregion

            HttpWebRequest wr = ((HttpWebRequest)WebRequest.Create(this._downloadAddress));
            HttpWebResponse res = ((HttpWebResponse)wr.GetResponse());

            if (res.ContentLength == -1)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        private void t_downloadFile()
        {
            #region Check Up's
            if (!(this._downloadAddress.StartsWith("http://") || this._downloadAddress.StartsWith("www.")))
            {
                throw (new System.Net.ProtocolViolationException("The provided url is not valid (" + this._downloadAddress + ")"));
            }

            int pathPos = this._downloadFolder.LastIndexOf(@"\");
            string path = this._downloadFolder.Substring(0, pathPos) + @"";

            if (!(System.IO.Directory.Exists(path)))
            {
                throw (new System.IO.DirectoryNotFoundException("The provided path could not be found (" + this._downloadAddress + ")"));
            }
            #endregion

            HttpWebRequest wr = ((HttpWebRequest)WebRequest.Create(this._downloadAddress));
            HttpWebResponse res = ((HttpWebResponse)wr.GetResponse());
                
            this._connectionState = ConnectionState.Connecting;
            this._fileSize = res.ContentLength;

            //I changed this part!
            if(connectionStateChanged != null)
                connectionStateChanged(this);            

            System.IO.Stream streamIn = res.GetResponseStream();
            System.IO.FileStream streamOut = 
                new System.IO.FileStream(this._downloadFolder, System.IO.FileMode.Create);

            const int BUFFER_SIZE = 4096;
            byte[] buffer = new byte[BUFFER_SIZE];
            int iRead = streamIn.Read(buffer, 0, BUFFER_SIZE);
            int mRead = iRead;

            this._connectionState = ConnectionState.Connected;

            //I changed this part!
            if(connectionStateChanged != null)
                connectionStateChanged(this);

            while (iRead > 0)
            {
                streamOut.Write(buffer, 0, iRead);
                iRead = streamIn.Read(buffer, 0, 4096);
                mRead += iRead;
                this._downloaded = mRead;
                this._currentProgress = (double)mRead / (double)res.ContentLength * (double)100;

                //I changed this part!
                if(progressChanged != null)
                    progressChanged(this);
            }

            this._connectionState = ConnectionState.DownloadComplete;

            // Added this part
            if (connectionStateChanged != null)
                connectionStateChanged(this);

            streamIn.Close();
            streamOut.Close();
        }
    }

} 

[PT Exorcist]

im keep getting an:

An unhandled exception of type 'System.NullReferenceException' occurred in downloadclass.dll

Additional information: Object reference not set to an instance of an object.

omg

when i see the code and put the mouse over the event who's givin error it says the event = null..but i have the if (event != null) { } so this shouldnt happen...bah

[PT Exorcist]

man i swear i dont understand! i that thing about != null and it didnt work..but copied that part of ur code to my code and it worked...but they look exactly the same...omg..much tks

[pvb]

cool, skip this message.

[PT Exorcist]

now i hardcoded that in other parts of the code and worked smoth...thank u so much