Throwing Exceptions

[Jonathan Wood]

In code that I have enclosed in a try block, it's fairly common for me to
respond to error conditions with something like this:

throw new Exception("Some thing went horribly wrong!");

But I've noticed that system execptions contain information such as the line
number where the error occurred, while exceptions created using the line
above do not.

What is the secret for exceptions thrown by me to have detailed information
such as the line number?

Thanks.

Jonathan

[Ignacio Machin ( .NET/ C# MVP )]

Re: Throwing Exceptions

On Jun 4, 1:14 pm, "Jonathan Wood" <jw...@softcirc uits.comwrote:

In code that I have enclosed in a try block, it's fairly common for me to
respond to error conditions with something like this:
>
throw new Exception("Some thing went horribly wrong!");
>
But I've noticed that system execptions contain information such as the line
number where the error occurred, while exceptions created using the line
above do not.
>
What is the secret for exceptions thrown by me to have detailed information
such as the line number?
>
Thanks.
>
Jonathan

Hi,

It should, only that it will be where you throw the exception.
You can do several things.
- rethrow the same exception by using throw ;
- adding the thrown exception as the InnerException to the new
exception

[Peter Duniho]

Re: Throwing Exceptions

On Wed, 04 Jun 2008 10:14:11 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:

[...]
But I've noticed that system execptions contain information such as the
line number where the error occurred, while exceptions created using the
line above do not.
>
What is the secret for exceptions thrown by me to have detailed
information such as the line number?

The Exception instance has a StackTrace member that includes this
information.

I suppose you could also get the curent StackTrace yourself and format
that into your error message, but I'm not sure I see the point, given that
the Exception already has this information.

Pete

[Jonathan Wood]

Re: Throwing Exceptions

Sorry if I wasn't clear. There is no InnerException or exception to rethrow.
I'm creating my own exception. But it doesn't have line number information.

--
Jonathan Wood
SoftCircuits Programming

http://www.softcircuits.com

"Ignacio Machin ( .NET/ C# MVP )" <ignacio.machin @gmail.comwrote in
message
news:58379f4d-0c4b-47bb-9685-c58c72fb0402@z1 6g2000prn.googl egroups.com...
On Jun 4, 1:14 pm, "Jonathan Wood" <jw...@softcirc uits.comwrote:

In code that I have enclosed in a try block, it's fairly common for me to
respond to error conditions with something like this:
>
throw new Exception("Some thing went horribly wrong!");
>
But I've noticed that system execptions contain information such as the
line
number where the error occurred, while exceptions created using the line
above do not.
>
What is the secret for exceptions thrown by me to have detailed
information
such as the line number?
>
Thanks.
>
Jonathan

Hi,

It should, only that it will be where you throw the exception.
You can do several things.
- rethrow the same exception by using throw ;
- adding the thrown exception as the InnerException to the new
exception

[Jonathan Wood]

Re: Throwing Exceptions

It doesn't include line number information for exceptions that I create.

It does have stack trace information so there's no reason to mess with that.

--
Jonathan Wood
SoftCircuits Programming

http://www.softcircuits.com

"Peter Duniho" <NpOeStPeAdM@nn owslpianmk.comw rote in message
news:op.ub8koi2 c8jd0ej@petes-computer.local. ..

On Wed, 04 Jun 2008 10:14:11 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:
>

>[...]
>But I've noticed that system execptions contain information such as the
>line number where the error occurred, while exceptions created using the
>line above do not.
>>
>What is the secret for exceptions thrown by me to have detailed
>information such as the line number?

>
The Exception instance has a StackTrace member that includes this
information.
>
I suppose you could also get the curent StackTrace yourself and format
that into your error message, but I'm not sure I see the point, given that
the Exception already has this information.
>
Pete

[Peter Duniho]

Re: Throwing Exceptions

On Wed, 04 Jun 2008 12:06:48 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:

It doesn't include line number information for exceptions that I create.

Really? When you call StackFrame.GetF ileLineNumber() on the frame of the
StackTrace you're interested (the lowest frame, for example, which would
be where the exception was thrown), you get something other than the
correct line number?

That's odd.

It does have stack trace information so there's no reason to mess with
that.

The stack trace information should include line numbers for every frame in
the stack for which debug symbols exist (which presumably would include
all of your own code).

Pete

[Jonathan Wood]

Re: Throwing Exceptions

Peter,

Really? When you call StackFrame.GetF ileLineNumber() on the frame of the
StackTrace you're interested (the lowest frame, for example, which would
be where the exception was thrown), you get something other than the
correct line number?

I haven't tried that. Don't even know what it means. Exception doesn't have
a StackFrame member, nor does Exception.Stack Trace.

What I'm doing is displaying the exception using plain-ol' ex.ToString(). In
exceptions generated by the frameworks, this produces a description of the
error, followed by stack trace information, followed by the line that
generated the error. In exceptions that I create, it produces a description
of the error, followed by stack trace information, but no line number. I'd
like my own exceptions to produce line numbers in this scenario.

The stack trace information should include line numbers for every frame in
the stack for which debug symbols exist (which presumably would include
all of your own code).

Here's what ex.ToString() produces for an exception that I created and
threw:

System.Exceptio n: Invalid menu item information received (2975)
at ASP.fooddelete_ aspx.Page_Load( Object sender, EventArgs e)

--
Jonathan Wood
SoftCircuits Programming

http://www.softcircuits.com

[Peter Duniho]

Re: Throwing Exceptions

On Wed, 04 Jun 2008 15:05:25 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:

>Really? When you call StackFrame.GetF ileLineNumber() on the frame of
>the StackTrace you're interested (the lowest frame, for example, which
>would be where the exception was thrown), you get something other than
>the correct line number?

>
I haven't tried that. Don't even know what it means. Exception doesn't
have a StackFrame member, nor does Exception.Stack Trace.

A StackTrace describes the entire call stack at the time of the
exception. A StackFrame is a single frame withing the call stack, and you
can retrieve the StackFrame instances from the StackTrace using the
GetFrame() or GetFrames() method.

Given that this information is already embedded in the Exception, via the
StackTrace, it's my opinion that adding it to the message itself is of
little value. However, if you really insist, you can always get the
current StackTrace before you create the Exception, and incorporate the
line number information into the string you use for the Exception.

Pete

[Jonathan Wood]

Re: Throwing Exceptions

Again, I do not want to add the line number to the Message property. I want
the line number to appear in the string returned by the ToString() method,
in just the same way it does when called on exceptions that were generated
by the framework.

I will see if I can see what you are referring to with regards to the
GetFrame() method, but it doesn't address the primary thing I'm trying to
understand/accomplish.

Jonathan

"Peter Duniho" <NpOeStPeAdM@nn owslpianmk.comw rote in message
news:op.ub802ho 18jd0ej@petes-computer.local. ..

On Wed, 04 Jun 2008 15:05:25 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:
>

>>Really? When you call StackFrame.GetF ileLineNumber() on the frame of
>>the StackTrace you're interested (the lowest frame, for example, which
>>would be where the exception was thrown), you get something other than
>>the correct line number?

>>
>I haven't tried that. Don't even know what it means. Exception doesn't
>have a StackFrame member, nor does Exception.Stack Trace.

>
A StackTrace describes the entire call stack at the time of the
exception. A StackFrame is a single frame withing the call stack, and you
can retrieve the StackFrame instances from the StackTrace using the
GetFrame() or GetFrames() method.
>
Given that this information is already embedded in the Exception, via the
StackTrace, it's my opinion that adding it to the message itself is of
little value. However, if you really insist, you can always get the
current StackTrace before you create the Exception, and incorporate the
line number information into the string you use for the Exception.
>
Pete

[Peter Duniho]

Re: Throwing Exceptions

On Wed, 04 Jun 2008 17:50:19 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:

Again, I do not want to add the line number to the Message property. I
want the line number to appear in the string returned by the ToString()
method, in just the same way it does when called on exceptions that were
generated by the framework.

Ah. Then you need to sub-class Exception and implement ToString()
yourself, so that it returns what you want.

I will see if I can see what you are referring to with regards to the
GetFrame() method, but it doesn't address the primary thing I'm trying
to understand/accomplish.

Well, you will need to understand it if you're going to include the line
number in your ToString() method. In that sense, it does address the
primary thing you're doing.

Pete

[Jonathan Wood]

Re: Throwing Exceptions

Okay, so you're saying the even though Exception.ToStr ing() does include
stack trace information, it does not include the line number. But that there
are system exceptions that override ToString() such that it does include the
line number.

If that's the case, I can deal with that. In fact, this is on a Web site
where I'm currently having exception data emailed to me. So I could simply
have my common handler form the proper string if regular Exceptions include
the line number.

I guess I figured that Exception.ToStr ing() was including the line number if
it was available. So, if not, then you've helped me understand this better.

Thanks.

--
Jonathan Wood
SoftCircuits Programming

http://www.softcircuits.com

"Peter Duniho" <NpOeStPeAdM@nn owslpianmk.comw rote in message
news:op.ub8419s t8jd0ej@petes-computer.local. ..

On Wed, 04 Jun 2008 17:50:19 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:
>

>Again, I do not want to add the line number to the Message property. I
>want the line number to appear in the string returned by the ToString()
>method, in just the same way it does when called on exceptions that were
>generated by the framework.

>
Ah. Then you need to sub-class Exception and implement ToString()
yourself, so that it returns what you want.
>

>I will see if I can see what you are referring to with regards to the
>GetFrame() method, but it doesn't address the primary thing I'm trying
>to understand/accomplish.

>
Well, you will need to understand it if you're going to include the line
number in your ToString() method. In that sense, it does address the
primary thing you're doing.
>
Pete

[Jonathan Wood]

Re: Throwing Exceptions

Peter,

A StackTrace describes the entire call stack at the time of the
exception. A StackFrame is a single frame withing the call stack, and you
can retrieve the StackFrame instances from the StackTrace using the
GetFrame() or GetFrames() method.

An example of this would be really, REALLY helpful for me.

According to Intellisense, Exception.Stack Trace is a string. Therefore, it
has no GetFrame() or GetFrames() method. I've looked high and low for these
methods. Any chance you can be a little more specific about where they are?

Jonathan

[Peter Duniho]

Re: Throwing Exceptions

On Wed, 04 Jun 2008 18:40:51 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:

Peter,
>

>A StackTrace describes the entire call stack at the time of the
>exception. A StackFrame is a single frame withing the call stack, and
>you can retrieve the StackFrame instances from the StackTrace using the
>GetFrame() or GetFrames() method.

>
An example of this would be really, REALLY helpful for me.
>
According to Intellisense, Exception.Stack Trace is a string. Therefore,
it has no GetFrame() or GetFrames() method. I've looked high and low for
these methods. Any chance you can be a little more specific about where
they are?

The methods are in the StackTrace class.

That said, my original reply was incorrect. I misremembered what the
StackTrace property provided, and mistakenly implied that it was an actual
StackTrace instance. Sorry about that.

But, since you are apparently going to need a sub-class anyway, it doesn't
matter. In your constructor, you can just use Environment.Sta ckTrace to
get the actual StackTrace instance, where you can either save that for
later use, or just immediately convert it to whatever string information
you actually want (including line numbers).

Pete

[Jonathan Wood]

Re: Throwing Exceptions

Environment.Sta ckTrace is also a string.

At any rate, none of this is coming together. I did some additional
searching and it looks like it might be an issue of whether or not debugging
is enabled and/or the PDB file is available. Although I don't exactly
recall, I may have been seeing those line numbers during testing on my
desktop machine, but now fail to get them on the Web server.

As near as I can tell, ex.ToString() will include stack trace information
and also line number information if it is available. It appears the
configuration on my Web server does not provide line number information.

Jonathan

"Peter Duniho" <NpOeStPeAdM@nn owslpianmk.comw rote in message
news:op.ub86kt1 d8jd0ej@petes-computer.local. ..

On Wed, 04 Jun 2008 18:40:51 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:
>

>Peter,
>>

>>A StackTrace describes the entire call stack at the time of the
>>exception. A StackFrame is a single frame withing the call stack, and
>>you can retrieve the StackFrame instances from the StackTrace using the
>>GetFrame() or GetFrames() method.

>>
>An example of this would be really, REALLY helpful for me.
>>
>According to Intellisense, Exception.Stack Trace is a string. Therefore,
>it has no GetFrame() or GetFrames() method. I've looked high and low for
>these methods. Any chance you can be a little more specific about where
>they are?

>
The methods are in the StackTrace class.
>
That said, my original reply was incorrect. I misremembered what the
StackTrace property provided, and mistakenly implied that it was an actual
StackTrace instance. Sorry about that.
>
But, since you are apparently going to need a sub-class anyway, it doesn't
matter. In your constructor, you can just use Environment.Sta ckTrace to
get the actual StackTrace instance, where you can either save that for
later use, or just immediately convert it to whatever string information
you actually want (including line numbers).
>
Pete

[Peter Duniho]

Re: Throwing Exceptions

On Wed, 04 Jun 2008 19:24:30 -0700, Jonathan Wood <jwood@softcirc uits.com>
wrote:

Environment.Sta ckTrace is also a string.

Note to self: stop trying to write posts while fixing dinner. :)

Anyway, I had that property in mind because I was reading something else
at the time. All you need to do is construct a new StackTrace instance.
It will automatically retrieve the current stack trace information.

At any rate, none of this is coming together. I did some additional
searching and it looks like it might be an issue of whether or not
debugging is enabled and/or the PDB file is available. Although I don't
exactly recall, I may have been seeing those line numbers during testing
on my desktop machine, but now fail to get them on the Web server.

Well, that's correct...unles s you have the correct symbols with your
executable, the stack trace cannot tell you the line number. I did
mention that before, and it's still true. :)

If when you include symbols with your executable, you find that the
default implementation of Exception.ToStr ing() does what you want, I
suppose that's all you really need to know.

Pete