Please help decipher this MSDN threading sample! - C# Discussion Boards

Re: trim byte[] to new size - after socket.receive

Ista10-Aug-03 13:14

10-Aug-03 13:14

byte[] trimmedData = new byte[recv];

Array.Copy(data, 0, trimmedData, 0, trimmedData.Length );

I'm not an expert yet, but I play one at work. Yeah and here too.

control the connection

Ahmed Mazrou39-Aug-03 17:16

Ahmed Mazrou3

9-Aug-03 17:16

hi i wanna ask about how can i control the connection of the internet of a pc within lan(lased line)
i mean how can i pause and restore the connection again in this pc

HINT: again the connect isn't dial up connection
it is lased line and all computers connected by network and the

connection of the internet within this lased line

thank you and i hope u can help me

Ahmed Mazrou3

Re: control the connection

Ista10-Aug-03 10:18

Ista

10-Aug-03 10:18

your going to need to use the wininet.dll to control internetconnect and few other functions from that library

http://www.c-sharpcorner.com/vbnet/vbcode/CallingWinInetVK.asp

This shows some examples

I'm not an expert yet, but I play one at work. Yeah and here too.

IF STATMENT

eggie59-Aug-03 17:01

eggie5

9-Aug-03 17:01

Here's my class...

using System;
using System.Windows.Forms;

namespace GPG__
{

	/// <summary>
	/// Summary description for logging.
	/// </summary>
	public class logging
	{
		LOG logForm=new LOG();
		aOut caller=new aOut();
		Form1 guiForm=new Form1();

		int k;
	
		public logging(string [] aLog, string start, string end, string duration, int delay, string file)
		{
			logForm.Show();
			
			logForm.listBoxLog.Items.Add(DateTime.Now.ToString("hh:mm:ss")+": Processing: "+file);

<big>			if(guiForm.checkBoxEnableDelay.Checked==true)
			{
				MessageBox.Show("CHECKED");
				logForm.listBoxLog.Items.Add(DateTime.Now.ToString("hh:mm:ss")+": Delay "+delay.ToString());
			}
			else
			{
				MessageBox.Show("NOT CHECKED");
			}</big>			
for (k=1; k<aLog.Length; k++)
				
				logForm.listBoxLog.Items.Add(DateTime.Now.ToString("hh:mm:ss")+": ["+aLog[k].ToString()+"]");
		}
	}
}

Now, look at the if statment asking if checkBoxEnableDelay is checked...

When ever I run this, it always evaluates to false, and the else stament runs... and yes, the box IS checked...

If I put the same code on my main FORM it runs fine...

WHat is the problem?

p.s. (ignore the broken for statment at the bottom... it's not like that in my code..._)

/\ |_ E X E GG

Re: IF STATMENT

eggie59-Aug-03 17:41

eggie5

9-Aug-03 17:41

hmm... I think it has somthing to do with if the check box is checked at form load, or not...

cause if I set the checkbox to checked in the PROPERTY EXPLORER, the if statment elvaluates to true. But if I un check it in the RUNNING FORM, it still evaluates to true...

and it's the same vice versa... if I uncheck it in the PROPERTY EXPLORER, it will elvauate to false, even if I CHECK it in the running FORM...

any ideas?

/\ |_ E X E GG

Re: IF STATMENT

Csharp™10-Aug-03 0:25

Csharp™

10-Aug-03 0:25

it's because you are declaring a " new " instance of Form1

eggie5 wrote:
Form1 guiForm=new Form1();

Form1 guiForm=new Form1();
..............................

why not add the checkbox to the logging sub, eg:

public logging(string [] aLog, string start, string end, string duration, int delay, string file,CheckBox cb)<br />
if(cb.Checked==true)<br />

Re: IF STATMENT

eggie510-Aug-03 18:23

eggie5

10-Aug-03 18:23

Thank you thank you.

your are a good man.

/\ |_ E X E GG

Please help decipher this MSDN threading sample!

devvvy9-Aug-03 16:26

devvvy

9-Aug-03 16:26

Thanks for taking time to respond to my question. I'm going over a threading sample from MSDN and is having a hard time trying to understand the sample:
(a) Monitor.Wait
(b) Monitor.Pulse
(c) waiting Vs ready queue in context of threading
(d) Why you need to add a "readerFlag" in the resource you are acquiring a lock on when you have already locked the resource using "lock( )" statement.

Before going further, reference to MSDN here:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vcwlkthreadingtutorial.asp

QUESTION 1:
"A lot of times there are a couple of steps to locking an object"
>> Q1-a: I don't get it. To lock and unlock an object:

Monitor.Enter(thisObj); //This won't return until you get the lock
thisObj.DoSomething();
Monitor.Exit(thisObj);

To try to lock and obj, use Monitor.TryEnter instead. But, in our MSDN sample:

public void WriteToCell(int n)
{
lock(this) // Enter synchronization block: The "lock()" block.
{
if (readerFlag)
{ // Why do you need this flag if you have already "lock" the resource???
}

} // Q1-b: Lock release here - my understanding correct?? This means you can do whatever you want in the "lock" block.? (Exiting THE "lock()"-block)

}
}

>> Q1-c: Once you acquire the lock (via Monitor.Enter or lock() function as in sample), NO other thread can acquire lock on "thisObj" until "Monitor.Exit". There's NO need for "readerFlag".

QUESTION 2:
Quote:
"Now that the cook is done, you go "hey over there, it's my turn! No one else is allowed to cut in front of me!" so you call
[
Monitor.Wait(this);
]"

>> Q2-a: Doesn't Wait function surrender lock to resource to next thread in "waiting queue". According to MSDN, Wait() does this:
* "Releases the lock on an object in order to permit other threads (in waiting queue) to lock and access the object."
* "Releases the lock on an object and blocks the current thread until it reacquires the lock."
My question is, why release lock BEFORE you actually do something (Read) with reseource?

public int ReadFromCell( )
{
lock(this) // Enter synchronization block: The "lock()"-block
{
if (!readerFlag) //WhY?? You ALREADY have the lock on "this" resource.
{
try
{
// Again, WHY!? You ALREADY have lock on "this" resource.
Monitor.Wait(this);
}
... catch statements...
}
Console.WriteLine("Consume: {0}",cellContents); //Q2-b: NOW you're reading - but why can't you read immediately after "lock(this)" statement???

readerFlag = false; // Q2-c: I have no idea why we need this flag.
// is done.
Monitor.Pulse(this); // Q2-d: I have no idea why we need to pulse - exitining the "lock()" block surrender the lock, other threads waiting for the resources will naturally be able to acquire it once execution exit the "lock()" block, why Pulse???

} // Exit synchronization block: The "lock()"-block
return cellContents;
}

>> Q2-f: waiting queue Vs ready queue - What the... It's in Monitor class documentation (.NET framework).

Help!

Re: Please help decipher this MSDN threading sample!

Meysam Mahfouzi10-Aug-03 17:31

Meysam Mahfouzi

10-Aug-03 17:31

I think by only changing one variable name you will get out the confusing situation you are in!;)

Just change 'readerFlag' name to 'dataAvailable'
You see? every thing's now clear, huh?

norm wrote:
public void WriteToCell(int n)
{
lock(this) // Enter synchronization block: The "lock()" block.
{
if (readerFlag)
{ // Why do you need this flag if you have already "lock" the resource???
}

} // Q1-b: Lock release here - my understanding correct?? This means you can do whatever you want in the "lock" block.? (Exiting THE "lock()"-block)

}
}

Suppose you want to read the cell, so you lock it, and you may see nothing is available in cell, so what should you do? Ahhhhaaaa, you should release the lock and wait until the writer puts some thing in cell and signals you to wake up, again acquire the lock and read the cell.

the same happens for writer, if cell is full, it will wait untill reader reads the cell.

I hope this helps Smile | :)

Don't forget, that's

Persian Gulf

not Arabian gulf!

Re: Please help decipher this MSDN threading sample!

devvvy11-Aug-03 2:56

devvvy

11-Aug-03 2:56

Well explained, let me go back and see if I truely understand it. Thanks.

norm

Re: Please help decipher this MSDN threading sample!

devvvy13-Aug-03 6:57

devvvy

13-Aug-03 6:57

Thanks a lot, gone thru the sample today.

norm

WSDL question

Mazdak9-Aug-03 9:52

Mazdak

9-Aug-03 9:52

When I developing my webservice can I edit WSDL file? I can't find this file in the folder of XML application.It create in my consumer application when I addd reference to it, so does this file create on the server?

Mazy

No sig. available now.

Re: WSDL question

James T. Johnson9-Aug-03 11:27

James T. Johnson

9-Aug-03 11:27

The WSDL is generated by passing a parameter to the webservice's .asmx file.

For the CP webservice (http://www.codeproject.com/webservices/latest.asmx) the WSDL is at: http://www.codeproject.com/webservices/latest.asmx?WSDL

Mazdak wrote:
When I developing my webservice can I edit WSDL file?

I don't think so, I think .NET always generates the WSDL file based on what the webservice offers.

James

"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972

Re: WSDL question

Ista9-Aug-03 12:13

Ista

9-Aug-03 12:13

Do a search for the wsdl file

or using the .net prompt type
wsdl /language:CS /out:<filename>.cs <webservicename>.wsdl

this creates your wsdl file or just do a serach for *.wsdl

its an xml file so you can easily edit it in vs, notepad, xml spy or whatever although I dont know of any valid reason to.

you can do it throuogh the IDE and then just edit it there

nick

I'm not an expert yet, but I play one at work. Yeah and here too.

Re: WSDL question

Mazdak10-Aug-03 1:54

Mazdak

10-Aug-03 1:54

Thanks for reply james.

Ista wrote:
you can do it throuogh the IDE and then just edit it there

But where can I save it? When user request it how can I force VS.NET use my wsdl, not create its own version?

Mazy

No sig. available now.

Re: WSDL question

Ista10-Aug-03 9:53

Ista

10-Aug-03 9:53

Its created based on your asmx file. What exactly are you trying to do so I can fully understand why you are trying to change it.

You might want to change the web service attributes in your class inorder to change that file. Because it is created based on your your web attributes and what not. Are you trying to build custom wsdl by client or what?

nick

I'm not an expert yet, but I play one at work. Yeah and here too.

code for email address validation on logon web application

gilstelzer9-Aug-03 6:09

gilstelzer

9-Aug-03 6:09

Hello all
I'm trying to create a logon web application and would like to check the validity of a new user's email address...
apart from string searching for '@' and '.' etc
I would like to check that the server exists and that there is an account for the new user (maybe use a ping somehow)

Thanks a lot
Roll eyes | :rolleyes:

gil s

Re: code for email address validation on logon web application

leppie9-Aug-03 7:36

leppie

9-Aug-03 7:36

As far as I know, there already is an email validator.

leppie ::AllocCPArticle(Generic DFA State Machine for .NET);

NUnit testing in Visual Studio

Will Ballard9-Aug-03 4:27

Will Ballard

9-Aug-03 4:27

I've published, in a first cut form, our plugin to Visual Studio .NET to
support integrated test runs of NUnit tests, complete with integrated
debugger support. It's totally free, and pretty handy -- please report your
bugs to help us improve it.

http://www.mailframe.net/Products/TestRunner.htm

Finding Char Index in current line

.gonad9-Aug-03 2:35

.gonad

9-Aug-03 2:35

this code shows me the current line and character index in a richtextbox control. the char index, however, is counted from position 0 at line 0 but i need the char index to start from 0 at each line and NOT from line 0.

how can i do this?

private void rtb1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)<br />
{<br />
<br />
//Shows the current Line of selection<br />
int Line = rtb1.GetLineFromCharIndex(rtb1.SelectionStart);<br />
MessageBox.Show(Line.ToString());<br />
				<br />
//Shows the Character Index of the selection<br />
int pos = rtb1.GetCharIndexFromPosition(new Point(e.X, e.Y));<br />
MessageBox.Show(pos.ToString());<br />
<br />
}

Thanks for your help.

.gonad

Re: Finding Char Index in current line

Ista9-Aug-03 5:12

Ista

9-Aug-03 5:12

the only way I might see is if you do this:

int Line = rtb1.GetLineFromCharIndex(rtb1.SelectionStart);

int pos = rtb1.SelectionStart;

while ( (newLine = rtb1.GetLineFromCharIndex(pos--) == Line)

MessageBox.Show("The beginning char index of the line is " + ++pos.ToString());

now that code is not tested I just typed it in but it should work for the char index of the first Line

MessageBox.Show(String.Format("Your caret is {0} characters away from the beginning",rtf1.SelectionStart - pos);

I'm not an expert yet, but I play one at work. Yeah and here too.

Re: simple messagebox

J. Dunlap8-Aug-03 22:42

J. Dunlap

8-Aug-03 22:42

It's a static method - no constructor needed.

System.Windows.Forms.MessageBox.Show("You must enter a name.", 
          "Name Entry Error",MessageBoxButtons.OK, 
           MessageBoxIcon.Exclamation);

"Blessed are the peacemakers, for they shall be called sons of God." - Jesus

"You must be the change you wish to see in the world." - Mahatma Gandhi

Re: simple messagebox

Ista9-Aug-03 9:53

Ista

9-Aug-03 9:53

uhh what are you talking about?

maybe its the wrong question assigned. lol

I'm not an expert yet, but I play one at work. Yeah and here too.

Barcode reader and Receipt printer

ChiYung8-Aug-03 19:53

ChiYung

8-Aug-03 19:53

Hi,

I'm working on a POS project using C# .NET. For now, I don't have a barcode reader and a receipt printer which are definitly a MUST for a POS system in the future.

I would like to know the nature of these two things, so that when i program the POS system, I know how to program as a way of using these two things.

I cannot purchase these two items before the completion of the project. So, I totally cannot try in my program or even know what it is. I want to program my system so that i do not need to have a big modification when i purchase these two things afterward.

Please help!

Re: Barcode reader and Receipt printer

AdrianT9-Aug-03 1:12

AdrianT

9-Aug-03 1:12

I have worked on a few POS systems in the past.

There are a few things to take into consideration.

1. What type of barcode scanner do you plan to use. If you are using a a wedge reader then the data that is read will be just like pasting a block of text into a edit box and it can be read simply. If the scanner is a COM port based scanner you will need to write a device driver or serial port capture routines to read the data. There is a good serail port class on this site http://www.codeproject.com/system/cserialport.asp.

2. Which barcode will you be using ??? Sometimes the barcode will contain additional characters that you are not interested in. The data that will be read in may have an extra characters at the start and/or end (e.g. check digit) depending on the barcode type and reader. Usually POS systems use the barcode EAN-13 (european standard) or EAN-8 (Which I think is the US standard)

3. POS Printer. You can simulate having a POS Printer. Do you have access to a printer? The only real programming difference between a POS printer is the width of the paper. You can setup your printer with a custom size paper that matches the width of the intended POS reciept printer and it will be just as if you has the receipt printer.

Hope this helps.

Smile | :)

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