Re: Rouge Text String in Socket Programing - C# Discussion Boards

29-Jul-09 4:04

Hello, I'm currently teaching myself asynchronous socket programing. Should mention I got the code here http://www.codeguru.com/csharp/csharp/cs_network/sockets/article.php/c8781#Client6[^] and have been editing it and improving it.

Anyway the problem I'm having is after I kick someone for trying to use a name someone else has or they change their name while they are connected to a name someone else has, a rouge string "\0" is sent seemingly from the client, even though when I kick the client and the socket is closed he still manages to send it. I know it happens after I send a message to the client.

The reason that this is kinda of a problem is because I'm using substring and of course the string is just too short.

I know I can just use an if sentence that makes it ignore everything that is fewer than x characters but I really want to know where this rouge text string is coming from.

Can someone help me?

Sorry about not posting the code but it is very long and I can't really pinpoint where the error is.

modified 27-Feb-21 21:01pm.

Nagy Vilmos29-Jul-09 4:59

29-Jul-09 4:59

Tumminn wrote:
The reason that this is kinda of a problem is because I'm using substring and of course the string is just too short.

So, before getting the substring, make sure the input is long enough. It is the programmer's job to validate the input and to manage whatever happens. It may well be that the client app is sending the string when it disconnects, but why are you even trying to process a message from a client session that yoou have rejected?

Panic, Chaos, Destruction.
My work here is done.

User 621557929-Jul-09 5:09

29-Jul-09 5:09

That is not my intention it just happens, I just want to know the reason for why I get this data. It only happens if I send a message to him then I get the string "\0" back for no reason.

Also I know about validating bit but I'm just curious why it happens.

modified 27-Feb-21 21:01pm.

Nagy Vilmos29-Jul-09 5:12

29-Jul-09 5:12

Is the client your own code too? Welcome to the wonderfull world of debug! Wink | ;)

Panic, Chaos, Destruction.
My work here is done.

User 621557929-Jul-09 6:21

29-Jul-09 6:21

Okay fixed the part about the changing names while server is live but still have the problem of it trying to receive data from a socket that is closed, which it shouldn't do but does anyway just to spite me.

This is the code to closing the socket (Server Side)

string msg = "Name Taken";
byte[] byData = System.Text.Encoding.Default.GetBytes(msg);
socketData.m_currentSocket.Send(byData);
socketData.m_currentSocket.Close();
m_workerSocketList.Remove(socketData.m_currentSocket);
m_clientCount--;

This is the code where is error happens (Server Side):

try
            {
                if (pfnWorkerCallBack == null)
                {
                    // Specify the call back function which is to be 
                    // invoked when there is any write activity by the 
                    // connected client
                    pfnWorkerCallBack = new AsyncCallback(OnDataReceived);
                }
                SocketPacket theSocPkt = new SocketPacket(soc, clientNumber);

                soc.BeginReceive(theSocPkt.dataBuffer, 0, theSocPkt.dataBuffer.Length, SocketFlags.None, pfnWorkerCallBack, theSocPkt);
            }
            catch (Exception se)
            {
                MessageBox.Show(se.Message);
            }

And last bit the client does when it is kicked:

if (m_clientSocket != null)
                        {
                            m_clientSocket.Close();
                            m_clientSocket = null;
                            UpdateControls(false);
                        }

Any ideas?

modified 27-Feb-21 21:01pm.

Nagy Vilmos29-Jul-09 6:48

29-Jul-09 6:48

I am just guessing here. Is the listener fully disconnected from the serve before or after sneding the FOAD message to the client? Try either removing the listener side of things BEFORE the disconnect message or WAITING for a disconnect from the client. I prefer teh first of the two.
If you have disconnect from the server end, then there is no way that the client can send you any EOS messages which is what I think you are getting.

Panic, Chaos, Destruction.
My work here is done.

User 621557929-Jul-09 6:55

29-Jul-09 6:55

I'm not quite sure how to do what you mean, thought I had done that by removing and closing the socket. Could you explain or give an example?
Also what does FOAD and EOS mean?

I'm still a little wet behind the ears here since I'm teaching myself this, so I apologize for the beginner questions.

modified 27-Feb-21 21:01pm.

Nagy Vilmos29-Jul-09 7:03

29-Jul-09 7:03

When you create the listener, you attach it to a listener event handler these need to be removed as well as releaseing the handle to the listener.

[FOAD - .... And Die, EOS - End of Stream]

[added]
These are not beginer questions, you're doing okay!

Panic, Chaos, Destruction.
My work here is done.

User 621557929-Jul-09 7:11

29-Jul-09 7:11

But if I were to release the listener wouldn't that mean that no more people could connect to the server?
Even if I did it temporarily wouldn't that dead period block people off from connecting?

Should have gotten the FOAD meaning though Laugh | :laugh:

modified 27-Feb-21 21:01pm.

Nagy Vilmos29-Jul-09 22:19

29-Jul-09 22:19

Not having the /exact/ code you are using, makes this an answer in theory.

When you receive the connection, you validate the session and give the session listener a handler that will process the events:

listener.DataReceived += new System.EventHandler(server_DataReceived);

When the sesseion is being disconnected, you need to disconnect the lsitener:

listener.DataReceived -= new System.EventHandler(server_DataReceived);

Panic, Chaos, Destruction.
My work here is done.

User 621557930-Jul-09 1:54

Re: Login form connectivity with SQL server 2005 with ADO.NET

30-Jul-09 1:54

I'm not quite sure I'm using that, like I said I'm still new at this, I'm using http://www.codeguru.com/csharp/csharp/cs_network/sockets/article.php/c8781#Client6[^] as a foundation so the connection, dataReceived etc are in there if you want to have a look.

Also if you want I can just send you what I have done so far and you can have a look at that. Smile | :)

modified 27-Feb-21 21:01pm.

Harpreet Singh Matharoo29-Jul-09 4:03

Harpreet Singh Matharoo

29-Jul-09 4:03

Hi Friends,
I'm Harry actually i'm fresher student in software engeenring line and i'm doing aa activity . I created a login form in Microsoft Visual Studio 2005 and I'm trying to store user id and password on back end. And I'm using this code for this purpose but every time it shows an error and error is when every time i fill the user id and pasword and i just click on login button and message box appear with meesage user id and password is wrong. plz help me in thsi activity. down here the code plz check it out the error .

private void button1_Click(object sender, EventArgs e)
{

SqlConnection con = new SqlConnection("Data Source=DEVILINSIDE\\SQLEXPRESS;Initial Catalog=master;Integrated Security=True");
SqlDataAdapter da = new SqlDataAdapter("select * from loginform", con);
con.Open();
SqlCommandBuilder cmb = new SqlCommandBuilder(da);
DataSet ds = new DataSet("dataset");
da.Fill(ds, "loginform");
DataTable dt = new DataTable();
dt = ds.Tables["loginform"];

foreach (DataRow dr in ds.Tables["loginform"].Rows)
{
if (textBox1.Text == dr[0].ToString() && textBox2.Text == dr[1].ToString())
{

welcome w = new welcome();
w.Show();

}
else
{
MessageBox.Show("Invalid User Name or Password", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
textBox2.Text = "";
}

}

Vimalsoft(Pty) Ltd29-Jul-09 4:50

Vimalsoft(Pty) Ltd

29-Jul-09 4:50

First of all you are doing this the Wrong way

First Create a Stored Procedure that does this

Create Procedure prclogin_check
(
@User_name varchar(20),
@U_Password varchar(23),
@Results int Output
)
IF EXISTS (Select * from User_Table
where User_name =@User_name and U_Password = @U_Password)
Set @Results =1

And after you are done with this , you have to do the Following in your C# Code

using System.Data.SqlClient;

String strcon = "User id = sa;Password= topman;Server=myServer;Database=MyDB";
            SqlConnection con = new SqlConnection(strcon);
            SqlCommand cmdselect = new SqlCommand();
            cmdselect.CommandTimeout = 0;
            cmdselect.CommandType = CommandType.StoredProcedure;
            cmdselect.Connection = con;
            cmdselect.CommandText = "prclogin_check";
            cmdselect.Parameters.Add("@Results",SqlDbType.Int,4);
            cmdselect.Parameters["@Results"].Direction = ParameterDirection.Output;
            int Res;

            try
            {
                con.Open();

                cmdselect.ExecuteNonQuery();
                Res = (int)cmdselect.Parameters["@Results"].Value;
                con.Close();

            }
            catch (SqlException e)
            {
                MessageBox.Show(e.Message);
            }using System.Data.SqlClient;

String strcon = "User id = sa;Password= topman;Server=myServer;Database=MyDB";
            SqlConnection con = new SqlConnection(strcon);
            SqlCommand cmdselect = new SqlCommand();
            cmdselect.CommandTimeout = 0;
            cmdselect.CommandType = CommandType.StoredProcedure;
            cmdselect.Connection = con;
            cmdselect.CommandText = "prclogin_check";
            cmdselect.Parameters.Add("@Results",SqlDbType.Int,4);
            cmdselect.Parameters["@Results"].Direction = ParameterDirection.Output;
            int Res;

            try
            {
                con.Open();

                cmdselect.ExecuteNonQuery();
                Res = (int)cmdselect.Parameters["@Results"].Value;
                con.Close();

            }
            catch (SqlException e)
            {
                MessageBox.Show(e.Message);
            }

And in your Business logic or in your Form you can create a Function that will test if the Count of Records is greater than 0,if its less than that , then its invalid login

Hope this Helps

Vuyiswa Maseko,

Few companies that installed computers to reduce the employment of clerks have realized their expectations.... They now need more and more expensive clerks even though they call them "Developers" or "Programmers."

C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.somee.com
http://www.vuyiswamaseko.tiyaneProperties.co.za
vuyiswa@its.co.za
http://www.itsabacus.co.za/itsabacus/

Datagridview DateTimePicker Problem.

priyamtheone29-Jul-09 3:31

priyamtheone

29-Jul-09 3:31

Can anyone provide me with a code example of how to use a datetimepicker cell in datagridview where in the
datetimepicker column i can set the value of any cell to null or to any datetime according to my choice. And the format of the datetimepicker cell should be dd MMM yyyy. I checked a lot of examples in the forums including articles by Nils Jonsson, Pham Minh Tri and Claudio Grazioli but none of them works when the DGV is databound. It works till u can select a date in a blank cell and save it. But when u try to delete an existing date from a cell it generates error saying 'Formatted value of the cell has a wrong type'. There's no way I can set a null value in a databound cell. I'm fed up of this. Plz help.

Find Scroll bar moved either left/right?

spalanivel29-Jul-09 3:15

spalanivel

29-Jul-09 3:15

Hi,
How to find whether horizontal scroll bar is moved right or left?

If its moved right then some code need to get execute and vice versa.

Thanks...

Reg,
Subbu

Re: Find Scroll bar moved either left/right?

Nagy Vilmos29-Jul-09 3:33

How can i see native code?

29-Jul-09 3:33

Two events to look at:

private void hsc_Scroll(object sender, ScrollEventArgs e) {
    // Occurs when the scroll box has been moved by either a mouse or keyboard action.
}

private void hsc_ValueChanged(object sender, EventArgs e)
{
    // Occurs when the System.Windows.Forms.ScrollBar.Value property is changed,
    // either by a System.Windows.Forms.ScrollBar.Scroll event or programmatically.
}

Panic, Chaos, Destruction.
My work here is done.

CP Please ignore

leckey29-Jul-09 4:55

leckey

29-Jul-09 4:55

This is the 5th version of the same question.

Back in the blog beatch!
http://CraptasticNation.blogspot.com/[^]

frommi29-Jul-09 3:10

frommi

29-Jul-09 3:10

Hi, i would like to explain my problem. I want to see the code when my applcation generate an exception.
I create a simple application that crash when a button is pressed:

private void button1_Click(object sender, EventArgs e)
{
Int32 Text;
Object obj= null;

Text= (Int32)obj;
}

This code generate a NullReferenceException when it try to make a cast of "obj".
Now, i run .exe file on a pc with only VS2008,when i click the button,jitdebugger start and ask me where is the file .cs.
My questions are:
Why the jitdebugger ask me where is the .cs file?
If i open module page (ctrl+alt+u) i see my file .exe with symbols loaded, but i can see the c# code.
Help me please.
Thank you, have a nice day
bye bye

MumbleB29-Jul-09 3:45

MumbleB

29-Jul-09 3:45

frommi wrote:
Why the jitdebugger ask me where is the .cs file?

Did you actually create a deployment app or are you just copying the .exe from the bin directory to another computer? This will not work.

As for the error, you might want to try the following.

Text = Convert.ToInt32(obj);

This will run without creating an error.

Excellence is doing ordinary things extraordinarily well.

PIEBALDconsult29-Jul-09 7:03

PIEBALDconsult

29-Jul-09 7:03

Kwagga wrote:
just copying the .exe from the bin directory to another computer? This will not work.

Sure it will. Debugging won't, but the app will (unless it throws an Exception Unsure | :~

Eddy Vluggen29-Jul-09 3:57

Eddy Vluggen

29-Jul-09 3:57

frommi wrote:
Why the jitdebugger ask me where is the .cs file?

There is no global exception handler in your application. Thus, you're asked whether or not you want to debug the application. The debugger will ask for the code-files to point out where the exception occurred.

frommi wrote:
If i open module page (ctrl+alt+u) i see my file .exe with symbols loaded, but i can see the c# code.

Symbols are provided by the .pdb file, and you'll only see the C# code when the debugger can find the appropriate source-code.

frommi29-Jul-09 4:08

frommi

29-Jul-09 4:08

well, i create the Release version of my simple application and i copy all Realese folder, it contains:

CrashDebug.exe
CrashDebug.exe.config
CrashDebug.pdb
CrashDebug.vshost.exe
CrashDebug.vshost.exe.config
CrashDebug.vshost.exe.manifest

and i set in .config file

configuration
system.windows.forms jitDebugging="true"
configuration

The error is created for start the debug and see the code.
But i can't see that.