Re: File transfer in C# - C# Discussion Boards

24-Jan-09 6:27

Hi,

File.ReadAllLines() does it all for you.

Smile | :)

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File transfer in C#

SimpleData24-Jan-09 4:17

24-Jan-09 4:17

Hi Lets think that there is a client and a server. Client wants to send three files with small sizes to the server. Server's ip address and port is static.

- Server starts listening the port and accepts all the connection attempts coming from any ip address.
- Client establishes a connection to the server. After connecting, starts to send the files.
- Server recieves the files and saves them to the hard disk.
- Client disconnects.
- Server keeps listening the port and accepts all the connection attempts coming from any ip address.

Essentially, this is what I am trying to do. I am not a starter in C# but I am not advanced too. I have designed the code but only first file out of three is recieved by server without a problem. Because client or server doesn't wait for transfer to be completed.

At the same time there can be more than one client connected to server, server should be able to recieve all the files.

Thanks in advance.

#realJSOP24-Jan-09 4:24

#realJSOP

24-Jan-09 4:24

It's called FTP. Learn it. Live it.

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
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SimpleData24-Jan-09 4:43

24-Jan-09 4:43

I know I can use FTP. But I should not use FTP because it is not secure. When you listen the network traffic with a sniffer you can easily see the username and password.

This software will be used by people and I don't want people to see the FTP login informations.

Dave Kreskowiak24-Jan-09 5:01

Dave Kreskowiak

24-Jan-09 5:01

Can Selçik wrote:
I know I can use FTP. But I should not use FTP because it is not secure. When you listen the network traffic with a sniffer you can easily see the username and password.

Really?? Google results for "Secure FTP[^]"...

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Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

SimpleData24-Jan-09 5:05

24-Jan-09 5:05

I think you are talking about FTPS.

How can I use FTPS client in C# and is there a FTPS server for linux?

Thanks.

EliottA24-Jan-09 5:49

EliottA

24-Jan-09 5:49

I think you're referring to SFTP[^], not FTPS.

SimpleData24-Jan-09 5:52

24-Jan-09 5:52

Actually I am referring to FTPS not SFTP. Because SFTP is doing his job over SSH and I don't want to risk console access. I prefer using FTPS. FTPS is doing his job with using SSL for encryption.

Security Information Internet

#realJSOP24-Jan-09 8:46

#realJSOP

24-Jan-09 8:46

Can Selçik wrote:
How can I use FTPS client in C#

You can buy a library, or write the code yourself.

Can Selçik wrote:
is there a FTPS server for linux?

Man, you're full of good questions today, aren't you?

I'm sure that if you took the time to use GOOGLE, you would find your answer.

trinm198724-Jan-09 4:14

trinm1987

24-Jan-09 4:14

When I open a page in the WebBrowser I see appear notice board:Security information
I want programmed to automatically remove this notice I do? I'm using language C #.NET

Re: Security Information Internet

Wendelius24-Jan-09 4:45

Wendelius

24-Jan-09 4:45

From inside a web page? You can't and for good reasons. For that purpose you would have to write your own (unsecure) browser.

The need to optimize rises from a bad design.My articles[^]

Re: Security Information Internet

trinm198724-Jan-09 5:04

trinm1987

24-Jan-09 5:04

Yes, I want to design a program WebBrowser.Toi will have a program like the user to browse the Web, the program will automatically answer the panel notification Security Information usually appears in a page.

Re: Security Information Internet

Dave Kreskowiak24-Jan-09 10:27

Dave Kreskowiak

24-Jan-09 10:27

trinm1987 wrote:
Yes, I want to design a program WebBrowser

That's a HUGE undertaking for a single person. It normally takes entire TEAMS of people a few years to write a browser from scratch. Good luck with that...

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Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

delegates and events

staticv24-Jan-09 3:23

staticv

24-Jan-09 3:23

// Holds the arguments for the StatusChanged event

public class StatusChangedEventArgs : EventArgs

{

    // The argument we're interested in is a message describing the event

    private string EventMsg;

 

    // Property for retrieving and setting the event message

    public string EventMessage

    {

        get

        {

            return EventMsg;

        }

        set

        {

            EventMsg = value;

        }

    }

 

    // Constructor for setting the event message

    public StatusChangedEventArgs(string strEventMsg)

    {

        EventMsg = strEventMsg;

    }

}

// This delegate is needed to specify the parameters we're passing with our event
public delegate void StatusChangedEventHandler(object sender, StatusChangedEventArgs e);

public static event StatusChangedEventHandler StatusChanged;

Okay, so in the above code, we created a delegate and a custom event.

// This is called when we want to raise the StatusChanged event

public static void OnStatusChanged(StatusChangedEventArgs e)

{

    StatusChangedEventHandler statusHandler = StatusChanged;

    if (statusHandler != null)

    {

        // Invoke the delegate

        statusHandler(null, e);

    }

}

What does the bold line do? Why do we check for null?

EDIT: The code is from C# Chat: Part 2 - Building the Chat Server (C# Programming Tutorial) • Geekpedia[^] check that out, if the above code doesn't provides what I mean.

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Do, or do not. There is no 'try'.

Re: delegates and events [modified]

Luc Pattyn24-Jan-09 3:29

24-Jan-09 3:29

Hi,

you make a local copy of StatusChanged, so the same value gets used both in the null-text and the invocation; StatusChanged is public, so it could be changed by another thread at any point in time; removing the last handler from it right after the null-test got executed would cause an exception in statusHandler(null, e);

In summary, without it your code would not be thread-safe.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

modified on Friday, June 10, 2011 12:01 PM

Re: delegates and events [modified]

staticv24-Jan-09 4:36

staticv

24-Jan-09 4:36

so the same value gets used both in the null-text and the invocation;

I'm sorry, but I didn't got it, what do you mean by null-text and the invocation?

I'm converting this code to C++/CLI so I don't know C#, that's why having little problems... Smile | :)

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Do, or do not. There is no 'try'.

Luc Pattyn24-Jan-09 4:54

24-Jan-09 4:54

if (statusHandler != null)     <--- that looks like a null-test
    // Invoke the delegate
    statusHandler(null, e);    <--- according to the comment this is an invocation

Luc Pattyn [Forum Guidelines] [My Articles]

modified on Friday, June 10, 2011 12:02 PM

staticv24-Jan-09 5:01

staticv

24-Jan-09 5:01

Hmmm, you wrote null-text Smile | :)

lol.. Thanks anyways

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Do, or do not. There is no 'try'.

Re: delegates and events [modified]

jkohler24-Jan-09 4:51

jkohler

24-Jan-09 4:51

Isn't that just making a copy of the reference?
And therefore no safer than testing/invoking directly on the original reference?

Subvert The Dominant Paradigm
-- bumper sticker, circa 1971

Luc Pattyn24-Jan-09 5:09

24-Jan-09 5:09

Yes, it copies a reference, making sure the event and the delegates inside it can not be garbage collected (it is a local copy). There still is a possibility that the event gets changed (it is kind of a linked list), to cope with that you could (probably should) add a try-catch around the invocation.

This is one of those rare cases where an empty catch block would be fine: after all, if another thread is allowed to remove the last delegate, that really means there is no need to call it anymore.

Have a look at the fine article Giorgi provided.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

modified on Friday, June 10, 2011 12:02 PM

jkohler24-Jan-09 6:48

jkohler

24-Jan-09 6:48

ahhh... reference to empty versus null reference. Got it.

Now I have to rework a whole bunch of code... I foresee a generic solution

Subvert The Dominant Paradigm
-- bumper sticker, circa 1971

DaveyM6924-Jan-09 4:13

DaveyM69

24-Jan-09 4:13

Luc's answer is perfect.

In addition, there's no need to declare your own delegate (from 2.0 onwards). Instead, just declare the event...

public event EventHandler<StatusChangedEventArgs> StatusChanged;

and in the OnStatusChanged...

EventHandler<StatusChangedEventArgs> statusHandler = StatusChanged;

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Luc Pattyn24-Jan-09 4:54

24-Jan-09 4:54

Luc Pattyn [Forum Guidelines] [My Articles]