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Debug Error Handling

Posted on 2009-04-10
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Last Modified: 2012-05-06
I have a small querry . It works of but if you press cancel small problem in debuger.
I need a way to handle it.

By the way it only does this in the debuger.
If i just run the exe it will do nothing. Is this someing to be worried about ?
var
  value : string;
 
begin
    value := InputBox('Invoice Number Lookup ', 'Please type your Number', '');
 if datamodule2.ADOQuery1.Locate('InvoiceNumber', Value, []) then
  ShowMessage('Record located')
  else
  ShowMessage('Record NOT LOCATED');
end;

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Question by:Grant Fullen
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5 Comments
 
LVL 22

Accepted Solution

by:
8080_Diver earned 250 total points
ID: 24120683
It works of but if you press cancel small problem in debuger.
I need a way to handle it.

Please explain what you mean by "if you press cancel".  If you are referring to the Cancel button on the Dialog box, then you need to look at the Default String parameter in your InputBox statement . . . it is a null string.  That could weel be the cause of your problems.  If you do not want toeven attempt to locate a record, then you need to code for that.
Also, you should get in the habit of using TRY . . . EXCEPT . . . END; to wrap code that has a potential for throwing exceptions.  That lets you, among other things, add a little more debugging or human consumable text to the error message (see below).  
Substituting the code snippet for your code should, among other things, make the exception message a little more meaningful if in no other way than that it will show you what was entered for the search parameter.  


var
  value : string;
 
begin
  value := InputBox('Invoice Number Lookup ', 
                    'Please type your Number', '');
  if  (Value = '')
  then begin
    ShowMessage('You clicked Cancel.');
  end
  else
    try
      if datamodule2.ADOQuery1.Locate('InvoiceNumber', Value, []) 
      then begin
        ShowMessage('Record located');
      end
      else begin
        ShowMessage('Record NOT LOCATED');
      end; {if}
    except E:Exception
      on exception
        begin
          Raise Exception.Create('ERROR: An error occured while ' +   
                                 'trying to locate the desired ' +   
                                 'record [' + Value + ']:' + #13#10 +
                                 E.Message);
        end;
    end; {try}
  end; {if}
end;

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Author Comment

by:Grant Fullen
ID: 24120790
Thanks for your reply.
except E:Exception  <========= Undeclaired Identifier......
0
 
LVL 37

Expert Comment

by:Geert Gruwez
ID: 24121078
Add SysUtils to the uses clause
0
 

Author Comment

by:Grant Fullen
ID: 24122006
wow thats   weard I allready have SysUtils in my uses clause...........
0
 
LVL 37

Expert Comment

by:Geert Gruwez
ID: 24122708
uh no, it's a syntax error

 except
      on E:Exception do
        begin
          Raise Exception.Create('ERROR: An error occured while ' +  
                                 'trying to locate the desired ' +  
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