.NET (Core and Framework)

15-Nov-05 7:33

Hello.
I'm trying to make a tread-safe class, by protecting read/write over its internal properties with locks, like this:

public void Set(string lats)
{
lock(this.LatS)
{
this.LatSex = lats;
}
}

public string Get()
{
string _aux;
lock(this.LatSex)
{
_aux = this.LatSex;
}
return _aux;
}

It does compile with strings, but not with decimal type... I cant figure why.

Does decimal time really need lock protection for thread-safe?
And what about strings and enumerations?

Thank you very much!!

Marc Clifton15-Nov-05 13:18

Marc Clifton

15-Nov-05 13:18

If you read the help on lock, it will say "expression must be a reference type". decimal is a value type. You don't need to lock value types, as nobody can modify them. Only reference types, something that may be referenced in many places, can be locked. Enumerations? Why would you lock on an enumeration? It's a constant.

Marc

VS2005 Tips & Tricks -- contributions welcome!

David Menéndez Cisterna17-Nov-05 11:34

17-Nov-05 11:34

Thanks for your response!
So... accesing (read/write) primitive types of .NET is an "atomic" operation. Is that so?

S. Senthil Kumar18-Nov-05 4:16

18-Nov-05 4:16

Only if the size of the aligned type is less than or equal to the size of a native integer.

Regards
Senthil
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S. Senthil Kumar18-Nov-05 4:18

18-Nov-05 4:18

No, lock operates only on reference types. If lock did accept a value type, it will get boxed. Now everytime a value type gets boxed, a new instance is created. Which means locking on it is useless, because every lock statement will lock on a new instance.

Reading and writing of value types is atomic only if the size of the aligned type is less than or equal to the size of a native integer.

Regards
Senthil
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David Menéndez Cisterna18-Nov-05 4:32

Create a ISAPI filter in .NET

18-Nov-05 4:32

Interesting... So, in order to protect a class' properties like doubles or decimals, do I need to use Mutex?

Thanks for your useful info!

leejo12314-Nov-05 21:38

leejo123

14-Nov-05 21:38

Is it possible to create a ISAPI filter in .NET. I had gone through a couple of articles that did not seem to help me.

My purpose for this filter is, I want to block access to a site if the Request comes from certain set of IP addresses.

Is it possible using C#?? Confused | :confused:

How do I go about creating one. Can some one please help me with it.

Cry | :((

Leejo

-- modified at 3:57 Tuesday 15th November, 2005

Problems serializing a subclass of an ArrayList

Skip.za13-Nov-05 3:07

Skip.za

13-Nov-05 3:07

Hi Folks,

I've got a bit of an irritating problem. I have a class which is a sublcass of an ArrayList. That class has an public propetry ID, which is a string. When I serialize the class the property does not get serialized. For instance I get something like this

<ArrayListSubclass>
  <Item />
  <Item />
</ArrayListSubclass>

But what I want is

<ArrayListSubclass ID="foo">
  <Item />
  <Item />
</ArrayListSubclass>

For some reason the attribute is left out, even though I mark it as an [XmlAttribute].

Any ideas why? Is there a declaration or directive I'm missing?

-- modified at 9:11 Sunday 13th November, 2005

Profile Switching?

Eustov12-Nov-05 9:12

Eustov

12-Nov-05 9:12

How do I programmatically switch the phones profile (e.g. to silent), searched all over the web and cant find any good answers.. I’m assuming this cant be don’t via C# and has to be done via C++ unmanaged code ?

Any help would be useful, code samples would be amazing Wink | ;-)

Cant believe its so hard todo such a simple task..

Nb. Using VS2005 & Windows Mobile 5 SmartPhone SDK..

System.Net.Sockets for reading IP packets?

Tom Paluzzi11-Nov-05 4:47

Tom Paluzzi

11-Nov-05 4:47

I'm writing an application in C# that needs to sniff
all IP packets coming into a certain server. I've
tried to create a socket, bind, listening for
connections, but I'm getting an exception when i try
to listen on the created socket. It says "the operation
is not supported on the type of object".

I tried changing how I defined the IPEndPoint, and the
SocketType and ProtocolType enumerations when creating
the socket.

Does anybody know the correct setup of the socket in
order to inspect IP packets? Not at the TCP layer, but
lower in OSI model.

Is
Here's the code.

Thx,
Tom

try
{
// Build local end point
IPAddress localAddr = IPAddress.Parse(Constants.LOCALHOST);
IPEndPoint endpoint = new IPEndPoint(localAddr, Constants.PORT);

// create new IP socket.
server = new Socket(AddressFamily.InterNetwork,SocketType.Raw,ProtocolType.IP);

// SetupSocket(server);

// Bind the socket to the local IP addr and port
server.Bind(endpoint);

// Start listening for connections, allowing for max # to be queued.
server.Listen(Constants.MAX_CONNECTION_QUEUE);

// loop until the service is stopped.
while (ServiceStarted)
{
// Wait asynchronously for connections to be accepted.
server.BeginAccept(new AsyncCallback(this.AcceptCallback), server);

// yield
if (ServiceStarted)
{
Thread.Sleep(new TimeSpan(0, 0, 5));
}
.
.
.
}
}
catch(SocketException e)
{
throw e;
}

Re: System.Net.Sockets for reading IP packets?

S. Senthil Kumar13-Nov-05 19:03

forms.timer vs thread.timer

13-Nov-05 19:03

AFAIK, what you are attempting to do can't be done using the .NET API as it provides only application level operations.

Regards
Senthil
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David Menéndez Cisterna10-Nov-05 6:26

Re: forms.timer vs thread.timer

10-Nov-05 6:26

Hello!!

Whats the real difference between these two timers? I read the MSDN but didnt understand very well.

Which one is better for main UI updating (labels... etc)?

Many THANKS!!!!!

PD: all of these is refered to Compact Framework 1.1

S. Senthil Kumar10-Nov-05 19:04

Re: forms.timer vs thread.timer

10-Nov-05 19:04

The Forms timer fires on the UI thread, which means you don't have to do Invoke/BeginInvoke when updating UI controls. But because it fires on the UI, it is not very accurate and is dependent on your application not holding up the message pump.

The Thread timer runs on a threadpool thread and will therefore fire more accurately. However, you'll need to do Invoke/BeginInvoke if you're updating UI elements.

Regards
Senthil
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David Menéndez Cisterna11-Nov-05 2:01

Retrieving Public Contacts from Outlook

11-Nov-05 2:01

Thanks for your invaluable info! Big Grin | :-D

chrisrm9-Nov-05 20:29

chrisrm

9-Nov-05 20:29

I am writing a managed C++ app that must retrieve all shared public contacts from outlook. I have a list of 484 contacts - but my code retrieves always exactly 250 of them and then exceptions start occurring when converting the enumerated MAPIFolder items into ContactClass's in order to print out the details of the contacts.

Here is some of my code :

<code>
//----------------------------------
// Get Contacts
Outlook::NameSpaceClass* outlookNS = dynamic_cast<Outlook::NameSpaceClass*>(outLookApp->GetNamespace("MAPI"));

Outlook::MAPIFolder* publicFolder = outlookNS->GetDefaultFolder(Outlook::OlDefaultFolders::olPublicFoldersAllPublicFolders);

//Print out some basic info.
String* s = String::Format("You have access to {0} public Outlook folders.", __box(publicFolder->Folders->Count));
Log(s);

IEnumerator* en = publicFolder->Folders->GetEnumerator();

while(en->MoveNext())
{
Outlook::MAPIFolder* item = dynamic_cast<Outlook::MAPIFolder*>(en->Current);
if (item)
{
String* st = String::Format("-> Public Folder: {0}", item->Name);
Log(st);

if (item->Name->Equals("My Shared Contacts"))
{
//Print out contact info.
String* s = String::Format("You have access to {0} public contacts.", __box(item->Items->Count));
Log(s);

IEnumerator* i = item->Items->GetEnumerator();
int count = 0;
while (i->MoveNext())
{
if (i->Current)
{
try
{
if (count == 248)
{
Log("BANG! - from now on exceptions occur when performing conversion below");
}
Outlook::ContactItemClass* contact = dynamic_cast<Outlook::ContactItemClass*>(i->Current);
if (contact)
{
Log(String::Format("Item {0}",__box(count)));
Log(contact->ToString());
Log(contact->FileAs);

//Log(contact->LastName);
//Log(contact->Email1Address);
Log("--------------------------------");
}
}
catch(InvalidCastException* e)
{
//I end up here from item 250 onwards. why does this happen?
Log(e->Message);
}
}
count++;
}
break;
}
}
}
</code>

Urgent help needed

NityaKakkar9-Nov-05 19:14

NityaKakkar

9-Nov-05 19:14

Hi,

I am working on Microsoft Visual Studio .NET 2003 VC++. I have created a solution & i am trying Confused | :confused:

too build it & i am facing the following error:

LINK : warning LNK4001: no object files specified; libraries used
libcmtd.lib(crt0.obj) : error LNK2019: unresolved external symbol _main referenced in function _mainCRTStartup
Debug/MP1G.exe : fatal error LNK1120: 1 unresolved externals

When this error came i went to the properties in linker\system i changed the subsytem from Console (/SUBSYSTEM:CONSOLE) to Windows (/SUBSYSTEM:WINDOWS)
& in the advanced tab changed the entry point from mainCRTStartup to wWinMainCRTStartup.

But then the following error is coming:

LINK : warning LNK4001: no object files specified; libraries used
ibcmtd.lib(wwincrt0.obj) : error LNK2019: unresolved external symbol _wWinMain@16 referenced in function _wWinMainCRTStartup
Debug/MP1G.exe : fatal error LNK1120: 1 unresolved externals

How to solve this problem as fast as possible.

Thanks in advance Smile | :)

Re: Urgent help needed

S. Senthil Kumar13-Nov-05 19:06