How to correectly catch WM_COPYDATA ? - C# Discussion Boards

Judah Gabriel Himango5-Jun-07 8:18

5-Jun-07 8:18

try
{
}
catch(Exception error)
{
}

will catch all exceptions. However, this is not a recommended practice since it will also catch unrecoverable or systems exceptions (e.g. System.OutOfMemoryException, SecurityException, ThreadAbortException, etc.)

The best practice is to catch only the exceptions you can recover from. Otherwise, don't handle them.

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Judah Himango

Guffa5-Jun-07 9:28

Guffa

5-Jun-07 9:28

Judah Himango wrote:
will catch all exceptions

Well, not all, only .NET exceptions. To catch all exceptions, you have to specify a parameterless catch:

try {
   // code
} catch {
   // catches any exception
}

---
single minded; short sighted; long gone;

Judah Gabriel Himango5-Jun-07 11:11

5-Jun-07 11:11

Right, it will catch all .NET exceptions.

An empty catch will catch non-exception objects -- CLI languages are urged, but not required to, throw only System.Exception objects. However, I wouldn't call those exceptions anymore; those are thrown objects, not thrown exceptions, right?

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Guffa5-Jun-07 22:18

Guffa

5-Jun-07 22:18

Judah Himango wrote:
However, I wouldn't call those exceptions anymore; those are thrown objects, not thrown exceptions, right?

I would call an exception an exception, regardless of what object is thrown to handle it. The exception is the situation, not the object.

---
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Judah Gabriel Himango6-Jun-07 4:14

6-Jun-07 4:14

Ah, see, when I was talking about exceptions, I was talking about System.Exception-based classes. Anyways, I suppose it's not such a big deal.

*edit* after looking into this a bit, I see the framework also refers to non-System.Exception objects which are thrown as "exceptions" in the documentation - interesting! So, you were right.

Another interesting side note is the System.Runtime.CompilerServices.RuntimeCompatibilityAttribute which tells the CLR to wrap all non-System.Exception "exceptions" in a real exception class before throwing it.

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Kevin McFarlane5-Jun-07 11:23

Kevin McFarlane

5-Jun-07 11:23

I read somewhere that this has changed in .NET 2.0 and you don't need empty catch blocks anymore.

Kevin

Judah Gabriel Himango6-Jun-07 4:21

How to correectly catch WM_COPYDATA ?

6-Jun-07 4:21

There is a System.Runtime.CompilerServices.RuntimeCompatibilityAttribute for assemblies that tells the runtime whether to wrap all "exceptions" that do not derive from System.Exception with a System.Runtime.CompilerServices.RuntimeWrappedException. Maybe that's what you're thinking of?

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gapfulgence5-Jun-07 7:15

5-Jun-07 7:15

Hi,

I'm struggling with a problem. I want to catch a 'WM_COPYDATA' event that occurs in a C# application.
I send a data from a C++ application. The bridge is correctly done I think.
So, sometimes it works, usually when my C# application is active.
But most of the time, it doesn't work, because when trying to catch the appropriate WM_COPYDATA message in WndProc overrided method of my C# application, the program stays catching a couple of other messages like: WM_WINDOWPOSCHANGED, WM_ACTIVATEAPP, WM_NCACTIVATE, WM_ACTIVATE and so on.
Doing so, it almost never catch the WM_COPYDATA message that I sent from my C++ application.

Can you help me please ?

Thanks.
P.S.: I catch messages in my C# application like this:

protected override void WndProc(ref Message m)
{
string g = m.ToString();

if (m.Msg == WM_COPYDATA)
{
// instructions.
}
}

p.f. Goudjo-Ako

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p.f. Goudjo-Ako

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kubben5-Jun-07 7:23

kubben

5-Jun-07 7:23

You really need to add:

else //Let the normal windows messaging process it.
  {
   base.DefWndProc(ref m);
  }

So that other windows messages get handled properly. I don't know if this will fix your issue or not. I am not sure if your C# app will receive the message if it is not active.

Ben

gapfulgence5-Jun-07 8:07

5-Jun-07 8:07

I already had:

base.WndProc(ref m);

Isn't it supposed to do the same thing ?

I tried what u asked me, but my c# application doesn't receive any information back.

thx.

p.f. Goudjo-Ako

Bringing our energy together !

kubben5-Jun-07 8:08

kubben

5-Jun-07 8:08

It is the same thing, I guess you didn't post that code in your previous post.

Ben

gapfulgence5-Jun-07 8:21

5-Jun-07 8:21

Yes, I didn't post it.

I also tried to use PostMessage instead of SendMessage. But I don't get appropriate results.

Any idea ?

Thx.

p.f. Goudjo-Ako

Bringing our energy together !

kubben5-Jun-07 8:34

kubben

5-Jun-07 8:34

Have you looked at this article at all:
http://www.codeproject.com/csharp/wm_copydata_use.asp[^]

It seems this is doing what you want to do.

Ben

gapfulgence6-Jun-07 2:15

regarding xml serialization [modified]

6-Jun-07 2:15

thanks.

p.f. Goudjo-Ako

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ksrs5-Jun-07 7:09

5-Jun-07 7:09

Hi all,
i have a class that that contains 3 class objects and 3 dataset proerties.
how can i use xml serialization to this class?

i am using xml serialization technique in .net 2005,i got the xml file but it contains xml schema file also. that comes in built at the time of serialization.is there any xml attributes or any method to seperate or disable the xmlschema file with xml file.

is it possible convert the dataset property to arraylist property at the time of serialization?
can any one help me please?

Thnaks
Raja

-- modified at 13:15 Tuesday 5th June, 2007

Not Active5-Jun-07 7:34

Not Active

5-Jun-07 7:34

Implement IXmlSerializable

only two letters away from being an asset

ksrs5-Jun-07 7:38

5-Jun-07 7:38

Hi thanks for answering. i am new to xml and C# can u please how can i implemnet IxmlSerializable

Thanks
Raja

ksrs5-Jun-07 7:47

5-Jun-07 7:47

Hi mark can u please help me?
how can i apply ixmlserializable

Thanks
raja

Giorgi Dalakishvili5-Jun-07 8:01

Giorgi Dalakishvili

5-Jun-07 8:01

Have a look at this: http://msdn2.microsoft.com/en-us/library/system.xml.serialization.ixmlserializable.aspx[^]

my articles

ksrs5-Jun-07 8:11