How to get the Exception number

  • Thread starter Thread starter RSB
  • Start date Start date
R

RSB

Hi Every one,
i am using the try Catch block..
and the Exception object has a Message Property but i want to Catch the
Error Number so that based on the Error number i can display Different error
message....

try{

}

Catch (Exception ex)
{
errNum = ex.?????
if (errNum == x) {
do x
}
else if ( errNum == y) {
do y
}
}


so how do i find the Error Number here..

Thanks
RSB
 
RSB said:
i am using the try Catch block..
and the Exception object has a Message Property but i want to Catch the
Error Number so that based on the Error number i can display Different error
message....

try{

}

Catch (Exception ex)
{
errNum = ex.?????
if (errNum == x) {
do x
}
else if ( errNum == y) {
do y
}
}


so how do i find the Error Number here..
Click to expand...

Exception.HResult may be what you're after. Can you definitely not
achieve this by catching different types of exception though? That's
the usual practice.
 
Hi,

There is no such beast (take a look at the Exception base class, at its
property and method... if it is not there, ... it is not there).

You should use the Exception derived class, from the particular to the
most general:



catch(ArgumentOutOfRangeException ex)
{
...
}
catch( ArgumentException ex)
{
...
}
catch (SystemException ex)
{
...
}

and so on.

You can "parse" the Exception.Message, or read the
Exception.InnerException, or StackTrace, etc. to get more info about the
nature of the error, but a try-catch is, by nature, a termination model, not
a resumption model of error handling... you loose the context, the
environment of the error, since the try scope is done, finish, out, dead.

You can throw a new exception, with a new message, of with a message
based on the existing message.



Hoping it may help,
Vanderghast, Access MVP
 
Thanks Jon and Michel
that helps me..

Michel Walsh said:
Hi,

There is no such beast (take a look at the Exception base class, at its
property and method... if it is not there, ... it is not there).

You should use the Exception derived class, from the particular to the
most general:



catch(ArgumentOutOfRangeException ex)
{
...
}
catch( ArgumentException ex)
{
...
}
catch (SystemException ex)
{
...
}

and so on.

You can "parse" the Exception.Message, or read the
Exception.InnerException, or StackTrace, etc. to get more info about the
nature of the error, but a try-catch is, by nature, a termination model, not
a resumption model of error handling... you loose the context, the
environment of the error, since the try scope is done, finish, out, dead.

You can throw a new exception, with a new message, of with a message
based on the existing message.



Hoping it may help,
Vanderghast, Access MVP
Click to expand...
 
So how do i cappture..
Object reference not set to an instance of an object.
i mean what type of Exception i catch there.

thanks
 
RSB,

If you are trying to detect when a variable is set to null, and a
property/method/field is trying to be accessed, then look for the
NullReferenceException.

Hope this helps.
 
RSB said:
So how do i cappture..
Object reference not set to an instance of an object.
i mean what type of Exception i catch there.
Click to expand...

NullReferenceException.

(If you can get to the message, surely you can also see what type of
exception you've got, can't you?)
 
Hi,


Sounds to me to be a System.NullRefereneException. At least, the
following code does:

try
{
string a = null;
int i = a.Length;
}
catch(NullReferenceException ex)
{
return;
}
catch(Exception ex)
{
return;
}


Place a stop point at each return, start a debug session. If you got
stop at the right return, no problem, you have the intended exception, else,
the catch(Exception ex) should display, in the Locals view, under variable
ex, the exception class you are looking for. Not very high tech, I admit my
culpability...


Hoping it may help
Vanderghast, Access MVP
 
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