Re: Problem with arraylist assignment - C# Discussion Boards

Question on SocketOptionName.ReceiveTimeout

yccheok9-Dec-02 17:50

9-Dec-02 17:50

i obtain a socket through TcpListener using:
Socket mySocket = myListener.AcceptSocket() ;//myListener is TcpListener

sometimes, i realize that my program will halt at line:
int i = mySocket.Receive(bReceive,bReceive.Length,0) ;

hence, i was thinking to set a receive timeout option, my questions is
(1)is this the correct method
mySocket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.ReceiveTimeout, 1000)

i put SocketOptionLevel as SocketOptionLevel.Tcp, is it correct?

(2)what will happen when the program come to line
int i = mySocket.Receive(bReceive,bReceive.Length,0) ;

and after 1000 miliseconds and still have not received anything. where will the program execution go?

thank you.

regards
yccheok

Re: Question on SocketOptionName.ReceiveTimeout

grv57513-Dec-02 4:07

grv575

13-Dec-02 4:07

1) I'm using
socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, 60000);
socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 60000);
socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveBuffer, 1024);
socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay, 1);

So I think it should be SocketOptionLevel.Socket. Found it elsewhere on google.

2) Set a breakpoint on that line and trace over it. It will either fire an exception or go to the next line. Don't quite remember. Check the return values for receive as well.

Running Application In Another Process Without Showing Console Window

yccheok9-Dec-02 17:49

yccheok

9-Dec-02 17:49

i try to run an console application through a programmatically created process. i dont want a new console command window to pop up during the process running. hence, i use the following code.

------
System.Diagnostics.ProcessStartInfo pi = new System.Diagnostics.ProcessStartInfo(Application.StartupPath+"\\EncodeFile.exe");
pi.CreateNoWindow = true;
p = new System.Diagnostics.Process();
p.StartInfo = pi;
p.Start();
------

however, the console command window still show up although i oledi set
pi.CreateNoWindow = true;

can anyone tell me the solution?

thank you.

regards
yccheok

Re: Running Application In Another Process Without Showing Console Window

Kannan Kalyanaraman9-Dec-02 22:47

Kannan Kalyanaraman

9-Dec-02 22:47

try it with the compiler option /target:winexe

Cheers
Kannan

Re: Running Application In Another Process Without Showing Console Window

Richard Deeming10-Dec-02 0:03

Richard Deeming

10-Dec-02 0:03

You need to set the RedirectStandardInput, RedirectStandardOutput and RedirectStandardError properties of the <EDIT>ProcessStartInfo</EDIT> object to true. If you need to, you can then access the input and output of the console using the StandardInput, StandardOutput and StandardError properties.

E.g.:

ProcessStartInfo psi = new ProcessStartInfo();
psi.RedirectStandardInput = true;
psi.RedirectStandardOutput = true;
psi.RedirectStandardError = true;
psi.FileName = "Path to the exe";
Process p = Process.Start(psi);

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Problem with arraylist assignment

djkno39-Dec-02 13:59

djkno3

9-Dec-02 13:59

<br />
((Rectangle)mySquares[i]).X = <br />
((Rectangle)mySquares[i-1]).X;

I have an ArrayList of Rectangles and would like to update the X co-ordinate with the old one but this assignment generates a compiler error "The left-hand side of an assignment must be a variable, property or indexer"
yet the left hand side of this IS a property. Is there a reason for this? do I have to extract/assign the x co-ordinates in a for loop?

Re: Problem with arraylist assignment

Rob Graham9-Dec-02 14:58

Rob Graham

9-Dec-02 14:58

If this is not already in a for loop, then how is the current value of i determined?
in any event, it will fail for i=0 since there is no element whose index = -1.
Perhaps we need a to see just a wee bit more of your code in order to help?;) Suspicious | :suss:

Re: Problem with arraylist assignment

djkno39-Dec-02 21:18

djkno3

9-Dec-02 21:18

<br />
for (i = mySquares.Count - 1; i > 0; i--)<br />
{<br />
((Rectangle)mySquares[i]).X = <br />
((Rectangle)mySquares[i-1]).X;<br />
((Rectangle)mySquares[i]).Y = <br />
((Rectangle)mySquares[i-1]).Y;<br />
}<br />

I'm trying to update the x,y co-ordinates of the rectangles in the arrary in a Timer.Tic() method.

it tells me that my left operand has to be a property but is Rectangle.X not a property?

Re: Problem with arraylist assignment

Burt Harris9-Dec-02 21:42

Burt Harris

9-Dec-02 21:42

Interesting, try this:

for (int i = mySquares.Count - 1; i > 0; i--) {
       Rectangle r1 = (Rectangle)mySquares[i];
       Rectangle r2 = (Rectangle)mySquares[i-1];
       r1.X = r2.X;
       r1.Y = r2.Y;
   }

Burt Harris

Re: Problem with arraylist assignment

James T. Johnson10-Dec-02 0:58

James T. Johnson

10-Dec-02 0:58

Burt Harris (msft) wrote:
Rectangle r1 = (Rectangle)mySquares[i];
Rectangle r2 = (Rectangle)mySquares[i-1];

Unfortunately that won't work either.

The problem is that Rectangle is a value type so the modifications you are doing are being done to the unboxed value which is discarded. Instead, you should create a new Rectangle object and place it back in the collection.

for (int i = mySquares.Count - 1; i > 0; i--) 
{
    Rectangle r1 = (Rectangle)mySquares[i]; 
    Rectangle r2 = (Rectangle)mySquares[i-1];      
 
    mySquares[i] = new Rectangle(r2.X, r2.Y, 
        r1.Width, r1.Height);
}

[Edit]I should have posted this sooner instead of catching up on CP, Richard beat me to it :P[/Edit]
James

- out of order -

Re: Problem with arraylist assignment

Richard Deeming10-Dec-02 0:13

Richard Deeming

10-Dec-02 0:13

Rectangle is a struct, so that probably won't work anyway, since you're changing the coordinates of an unboxed copy of your rectangle. Try something like:

for (i = mySquares.Count - 1; i > 0; i--)
{
    mySquares[i] = new Rectangle(
        ((Rectangle)mySquares[i-1]).Location,
        ((Rectangle)mySquares[i]).Size);
}

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Re: Problem with arraylist assignment

djkno310-Dec-02 6:11

djkno3

10-Dec-02 6:11

Thanks everyone for your replies it is working now (Well at least the assignment problem I had Laugh | :laugh:

goto in C#

afronaut9-Dec-02 11:05

afronaut

9-Dec-02 11:05

Is this the only way to 'fall through' on switch statements?

<br />
int x = 3;<br />
switch(x){<br />
case 0:<br />
goto case 1;<br />
case 1:<br />
goto case 2;<br />
case 2:<br />
goto case 3;<br />
...<br />
}<br />

*->>Always working on my game, teach me
*->>something new.
cout << "dav1d\n";

Re: goto in C#

leppie9-Dec-02 11:30

leppie

9-Dec-02 11:30

yes

DBHelper - SQL Stored Procedure Wrapper & Typed DataSet Generator for .NET

Re: goto in C#

Not Active9-Dec-02 13:14

Not Active

9-Dec-02 13:14

IMHO something like this would be a cludge that screams poor design.

If you need to use goto to 'fall through' a switch then you need to consider redesigning your application.

<br />
switch(x)<br />
{<br />
  case 0:<br />
  case 1:<br />
  case 2:<br />
    DoAction();<br />
    break;<br />
    .<br />
    .<br />
    .<br />
}<br />

Probably not what your doing though.

Re: goto in C#

ryancrawcour9-Dec-02 20:06

ryancrawcour

9-Dec-02 20:06

yeah indeed. perhaps you could consider getting each of your case statements to call functions instead of each other.

not sure what your exact need is, but all i know is from previous experience that fallthrough statements come back to bite you in the butt later when you least expect them.

Re: goto in C#

Christian Graus9-Dec-02 21:59

Christian Graus

9-Dec-02 21:59

No, you can 'fall' through so long as there is no code between the case statements.

And yes, it sucks.

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

Get system information

sammyh9-Dec-02 10:10

sammyh

9-Dec-02 10:10

Anyone know how to get system info at runtime. I specifically need to find out what COM ports are installed.

Thanks

-Sam

Re: Get system information

Kannan Kalyanaraman9-Dec-02 22:50

Kannan Kalyanaraman

9-Dec-02 22:50

Hi Sam,

Take a look at System.Management namespace, its a wrapper for WMI, you might find what you are looking for.

Cheers
Kannan

Re: Get system information

thematt10-Dec-02 2:41

thematt

10-Dec-02 2:41

Try this out:

private void btnComPorts_Click(object sender, System.EventArgs e)
{
txtOutput.Clear();
string server = @"\\" + txtServer.Text;
ManagementScope ms = new ManagementScope(server + @"\root\cimv2");
ObjectQuery oq = new ObjectQuery("select deviceID from win32_SerialPort");
ManagementObjectSearcher mos = new ManagementObjectSearcher(ms, oq);
ManagementObjectCollection moc = mos.Get();
foreach(ManagementObject mo in moc)
{
txtOutput.AppendText(mo["DeviceID"].ToString());
txtOutput.AppendText("\r\n");
}
}

Matt is a network administrator for an auditing company in the midwest. He is shamelessly looking for Windows programming side work.

Re: Get system information

sammyh11-Dec-02 5:50

sammyh

11-Dec-02 5:50

Thanks Matt, worked excellent!

Scrolling Credits

OBRon9-Dec-02 9:46

OBRon

9-Dec-02 9:46

I've seen many really good examples of how to add scrolling credits to your Visual C++ applications, but I haven't found any yet for a C# Windows application. Are there any out there?

null strings

grv5759-Dec-02 7:33

grv575

9-Dec-02 7:33

How can I test for a null string?

if (str == "")
doesn't work if str is a string containing just \0.

Re: null strings

peterchen9-Dec-02 7:59

peterchen

9-Dec-02 7:59

if (str == null)

[edit]Note that .NET makes a distinction between null and "" - both are possible. The first one throws a Null exception, when you try to use it, the second one bevaves like you expect from a zero-length string.[/edit]

If I could find a souvenir / just to prove the world was here [sighist]

Re: null strings

Richard Deeming10-Dec-02 0:15

Richard Deeming

10-Dec-02 0:15

So, if (str == null || str.Length == 0) then. Poke tongue | ;-P

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

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