Try Finally Except - Help

[Tony Stone]

I am trying to clean up a lot of my code messes.  I am trying to implement error handling where possible and this is my first go at use try...except... statements.  I have used them, typically what I copied from examples on the net.  I really need my procedure to exit or abort if an exception happens.  Simply calling exit; after the On E: EInOutError do gives me a compile error.  Expects end;

This is a sample of my attempt, can I only have one statement for the on E: do ... statement?

Code: Pascal  [Select][+][-]

1.   if dlgFMsaveTarget.Execute then
2.   begin
3.     // create target file
4.     try
5.       AssignFile(TargetFileOD, dlgFMsaveTarget.FileName);
6.       Rewrite(TargetFileOD);
7.       CloseFile(TargetFileOD);
8.     except
9.       on E: EInOutError do
10.         ShowMessage('File handling error occurred. Details: ' +
11.           E.ClassName + '/' + E.Message);
12.        //exit; // there was an error... need to get out of entire procedure
13.     end;
14.   end else exit; //user pressed cancel in dialog - get out of here
15.  startProcessing;
16.  
17.  

[Fantablup]

          except
            on E: EDatabaseError do
            begin
              ShowMessage( 'Database error: '+ E.ClassName + #13#10 + E.Message );
              ShowMessage( 'hey dude ');
            end;
            on E: Exception do
            begin
              ShowMessage( 'Error: '+ E.ClassName + #13#10 + E.Message );
            end;
          end;

[sstvmaster]

.
..Simply calling exit; after the On E: EInOutError do gives me a compile error.  Expects end;

...

Code: Pascal  [Select][+][-]

1. ...
2.     except
3.       on E: EInOutError do
4.         begin // <--
5.           ShowMessage('File handling error occurred. Details: ' + E.ClassName + '/' + E.Message);
6.           exit;
7.         end; // <--
8.     end;
9. ...

[Tony Stone]

DOH!!!!   


I feel I need to delete this post now!  I am embarrassed.  Thank you!  Or i'll just leave it for other newbies...

Grrr!  This was a simple lesson with if then statements.  I really canot beleive I posted this question in public... lol

.
..Simply calling exit; after the On E: EInOutError do gives me a compile error.  Expects end;

...

Code: Pascal  [Select][+][-]

1. ...
2.     except
3.       on E: EInOutError do
4.         begin // <--
5.           ShowMessage('File handling error occurred. Details: ' + E.ClassName + '/' + E.Message);
6.           exit;
7.         end; // <--
8.     end;
9. ...

[Fantablup]

Nothing to be embarrassed about.
We all have been there

[PascalDragon]

          except
            on E: EDatabaseError do
            begin
              ShowMessage( 'Database error: '+ E.ClassName + #13#10 + E.Message );
              ShowMessage( 'hey dude ');
            end;
            on E: Exception do
            begin
              ShowMessage( 'Error: '+ E.ClassName + #13#10 + E.Message );
            end;
          end;

Please use [ code ] tags when providing code as this way it's easier recognizable, provides a separate scroll region if it's large and also avoids the forum software possibly messing up parts due to its BBcode handling.

[dbannon]

And while we are being picky, much better to use the const, LineEnding instead of #13#10, it will work on all platforms, not just Windows.

 

Davo

[alpine]

I am trying to clean up a lot of my code messes.  I am trying to implement error handling where possible and this is my first go at use try...except... statements.  I have used them, typically what I copied from examples on the net.  I really need my procedure to exit or abort if an exception happens.  Simply calling exit; after the On E: EInOutError do gives me a compile error. 

Using AssignFile/RewriteFile/CloseFile raises exceptions with I/O checks enabled, by default they're not:

Depending on the state of the {$I} switch, a runtime error can be generated if there is an error. In the {$I-} state, use IOResult to check for errors.

I would use streams for the purpose.