Solved

send image via tcp/ip

Posted on 2008-10-30
3
2,174 Views
Last Modified: 2013-11-26
i am trying to send a picturebox image to a client computer using tcp.but im really struggling. i have converted the image to bytes before sending it. but i am having trouble converting the bytes back to image once it gets to the client. how do i determine the about of bytes to be read.
Server Side code'''''''''''''''''''''''''''''''''''''''

 Public Sub start()

        Listener.Start()

        Client = Listener.AcceptTcpClient

        Stream = Client.GetStream()

        '----

        w = New BinaryWriter(Stream)

        r = New BinaryReader(Stream)

        '----

        If r.ReadString() = "RequestConnect" Then

            w.Write("Connected")

            Do

                w.Write(imageToByteArray(Form1.PictureBox1.Image))

                w.Write("Connected")

            Loop Until r.ReadString() = "Disconnect"

            w.Write("Disconnected")

        End If

        Client.Close()

        Listener.Stop()

    End Sub

 

    Public Function imageToByteArray(ByVal imageIn As Image) As Byte()

        Dim ms As MemoryStream = New MemoryStream()

        imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.jpg)

        Return ms.ToArray()

    End Function

''---------------------------------------------------------------

 

CLIENT SIDE CODE''''''''''''''''''''''''''''''''''''''''''''''''''''

 Public Sub connect()

        Client.Connect(IP, port)

        Stream = Client.GetStream

        '----

        w = New BinaryWriter(Stream)

        r = New BinaryReader(Stream)

        '----

        

        w.Write("RequestConnect")

        If r.ReadString() = "Connected" Then

            Do

 ''HERES THE PROBLEM. how do i determine the amount of bytes to read

    Form1.PictureBox1.Image = byteArrayToImage(r.ReadBytes(126643))

                Application.DoEvents()

                w.Write("RequestConnect")

            Loop Until r.ReadString() = "Disconnected"

        End If

        Client.Close()

    End Sub

 

 Public Function byteArrayToImage(ByVal byteArrayIn() As Byte) As Image

        Dim ms As MemoryStream = New MemoryStream(byteArrayIn)

        Dim returnImage As Image = Image.FromStream(ms)

        Return returnImage

    End Function

Open in new window

0
Comment
Question by:carl5121
3 Comments
 
LVL 19

Accepted Solution

by:
drichards earned 250 total points
ID: 22846127
The best way to do it would be to send a header indicating the number of bytes to expect.  That way you can be sure to get them all.  Without that, the best you can do is to have a fixed size buffer (say 1024 bytes) and use the Read method.  You don't need the binary reader for this as it exists on the stream itself.

After doing a read, you transfer the bytes to a MemoryStream and then read again.  You read until no bytes are received for some period of time.  The problem is that you cannot predict the correct wait time as it might range from milliseconds to many seconds, or the data may not show up at all due to network conditions.  The most robust way to do it will be to send the image size in bytes ahead of the image data.  You'll need to make the header a fixed size so you know where the header ends and the image data starts.
0
 

Author Closing Comment

by:carl5121
ID: 31511682
thank you for your help. i've been looking for an answer for a week. i joined this website today and a good choice that was.
0
 
LVL 1

Expert Comment

by:agoud
ID: 25328194
This is how I do it with messages but it will have to be adapted to 'adding to the byte array'. I believe the keyphrase here is "While stream.DataAvailable". You will also have to use the stream (from Client.GetStream) directly. This is simply another way to do it.


While stream.DataAvailable

       i = stream.Read(bytes, 0, bytes.Length)

      Msg = Msg + System.Text.Encoding.ASCII.GetString(bytes, 0, i)

      Console.WriteLine("Received: {0}", Msg)

End While

Open in new window

0

Featured Post

Find Ransomware Secrets With All-Source Analysis

Ransomware has become a major concern for organizations; its prevalence has grown due to past successes achieved by threat actors. While each ransomware variant is different, we’ve seen some common tactics and trends used among the authors of the malware.

Join & Write a Comment

A basic question.. “What is the Garbage Collector?” The usual answer given back: “Garbage collector is a background thread run by the CLR for freeing up the memory space used by the objects which are no longer used by the program.” I wondered …
It seems a simple enough task, yet I see repeated questions asking how to do it: how to pass data between two forms. In this article, I will show you the different mechanisms available for you to do just that. This article is directed towards the .N…
Access reports are powerful and flexible. Learn how to create a query and then a grouped report using the wizard. Modify the report design after the wizard is done to make it look better. There will be another video to explain how to put the final p…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

707 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

9 Experts available now in Live!

Get 1:1 Help Now