Error handling - best practice 1

[AP81]

I was just interested to see other peoples approaches to error handling.

I usually use {try, except, finally}. This gets a bit tedious at times though. What method is the best to use?




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[TonHu]

There's Quick & Dirty, and there's Quick & Quality.
You trapping errors with try/except/finally goes in the Quick & Quality category.

HTH
TonHu

 

[AP81]

Thanks, but is this the right approach?

I am a VB programmer learning Delphi, so even though there is some similarity between the two, there is also a lot of differences.

With VB, I would tend to use, {try, catch, finally}, and {On Error GoTo ErrorHandler}.

Unfortunatley OnError is not supported in Delphi, and {try, finally] isn't trapping all of my errors (when attempting to connect to a database).

I use;

try
connection.open
except on E : Exception do
begin
connection.close
showmessage('Error')
end;
end;

What am I doing wrong?




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There's no place like 127.0.0.1
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[hilfy]

Try...Finally isn't about catching errors, it's for making sure a block of code will alway run regardless of whether there's an error or not. I use Try...Finally in a couple of specific situations:

- I've opened a table or query and I want to make sure that it gets closed even if there's an error.

- I've created an object (usually a TStringList) and I want to make sure it's freed even if there's an error.

For actually exception handling, you'll use Try...Except. Also, the "On E:Exception" will give you access to the actual error message. For example:

except
  on e:Exception do
  begin
    MyDatabase.Rollback;
    ShowMessage('Error in MyFunction-' + e.Message);
  end;
end;

-D

 

[lespaul]

exactly what I needed hilfy!! have another star!

les