Exception

[shapper]

Hello,

I have a function which communicates with a database:

Public Overloads Sub Create(ByVal name As String, _
ByVal comment As String)
Try
Dim dbBlog As Database = DatabaseFactory.CreateDatabase("MyDB")
Dim dbcBlog As DbCommand =
dbBlog.GetStoredProcCommand("CreateBlog")
dbBlog.AddInParameter(dbcBlog, "@BlogName", DbType.String, name)
dbBlog.AddInParameter(dbcBlog, "@BlogComment", DbType.String,
comment)
dbBlog.ExecuteNonQuery(dbcBlog)

Catch ex As SqlClient.SqlException
????????
End Try

End Sub

This is a function which is inside a library that will be compiled.
My question is how to let the user knows what is the exception?

1. Should I send the ex.string to console?
2. Should I return ex.String by making it a function instead of a sub?
3. Should I throw the exception inside my function? (I am not sure if
this is even necessary. See next question)

Catch ex As SqlClient.SqlException
throw(ex)
End Try

4. Should I move the Try, Catch block to the main user code like:

Try
Create("MyBlog", "This is my blog")
Catch ex As SqlClient.SqlException
????????
End Try

I really have no idea of how should I do this?
Remember the function is inside a class that will be compiled into a
DLL with the namespace Blogs.

Thanks,
Miguel

 

[Patrice]

I would consider using first a global error handler. My personal preference
is to display a generic error message to the user (this is an ASP.NET
application so the web page is your only communication vector with the user)
and mailing the error details to the development team.

You can use a local try block to clean up resources and/or in the rare cases
where the user could really do something about the error.

 

[shapper]

I would consider using first a global error handler. My personal preference
is to display a generic error message to the user (this is an ASP.NET
application so the web page is your only communication vector with the user)
and mailing the error details to the development team.

You can use a local try block to clean up resources and/or in the rare cases
where the user could really do something about the error.

Hi,

you mean I can display my error as ASP.NET usually displays errors (In
those pages where text is in red)?
How can I do this? Does this has a name so I can look in Google?

Thanks,
Miguel

 

[Patrice]

Try :
http://support.microsoft.com/kb/306355/en-us

and see the Application_Error event...

You'll then have a first point where to handle errors. You'll be able to add
then more local code (if you need to do sometying specific either for the
user or to clean up resources before letting the global error handler comes
into play).

--
Patrice

"shapper" <[email protected]> a écrit dans le message de (e-mail address removed)...

I would consider using first a global error handler. My personal
preference
is to display a generic error message to the user (this is an ASP.NET
application so the web page is your only communication vector with the
user)
and mailing the error details to the development team.

You can use a local try block to clean up resources and/or in the rare
cases
where the user could really do something about the error.

Hi,

you mean I can display my error as ASP.NET usually displays errors (In
those pages where text is in red)?
How can I do this? Does this has a name so I can look in Google?

Thanks,
Miguel

 

[sloan]

This is probably the best article on ExceptionHandling do and don'ts.

http://blogs.msdn.com/kcwalina/archive/2005/03/16/396787.aspx



Don't forget, you can write your code like this

Try
//do stuff
Finally
//clean up stuff
End Try


You don't have to use a Catch.

If all you do is this

Try
'do stuff

Catch ex As SqlClient.SqlException
throw ''notice just a "throw" and not a "throw ex"
end try

then just use a try/finally block

......................

The one place you might consider

Catch ex As SqlClient.SqlException

throw new UserFriendlyDatabaseException ("The database is currently
down. Please try again later.");

End Try

In this scenario, you create a custom exception. And you are hiding details
from your user, and you are giving them a more generic exception.
Especially on a public website, where you don't want to expose what the
Server/Database name is to the public.

Dont' overdo this, or abuse it. Read the article above and bookmark it.