Solved

Error handling in Delphi 1.0

Posted on 1997-10-16
5
199 Views
Last Modified: 2010-04-04
Hi...

I am a student who is beginning to use Delphi 1.0 .
Would you pleez send me an explaination of how to and/or the specific code on :

1) While entering information into a database, if the wrong type of information is entered into a field of a specific type Delphi produces an error causing the program to stop.
An example would be, when alphanumeric data is entered into a numeric field and the record is posted, an error is produced and the program is terminated.

I need help on how to handle this error by giving the user an error message without terminating the program so that the user can go back and correct such a problem.

2) When one tries to post data into a table that is not in edit or insert mode, an error is produced and the program terminates. This is in the case where one uses a DBNAVIGATOR button.
 
How does one go about avoiding such termination by being able to provide the user with a suitable message to go back correct the situation.

If my questions are not sufficiently clear or ambigious, please provide any helpful information and coding on one goes about handling errors in Delphi 1.0.

Your attention will be highly appreciated.

Yours sincerely  
Sprawler.
0
Comment
Question by:sprawler
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
5 Comments
 
LVL 3

Accepted Solution

by:
mirek071497 earned 50 total points
ID: 1347777
Hi
You must use try..except  or  try..finally statements

example

var
  st : string;
  lk : integer;
begin
  st :='23a3';
  try
    { place here instruction which can fail }
    lk := StrToInt( st );
  except
    { this was called on error }
    showmessage( 'bad integer format' );
  end;
end;
0
 

Author Comment

by:sprawler
ID: 1347778
Hi.. Again mirek

I am uncertain what code would go into the areas you labelled :

{Place here instruction which could fail}
{This was called on error}

Please suggest code using an example, if possible.
Tanx for the speedy response to my question.

sprawler
0
 
LVL 3

Expert Comment

by:mirek071497
ID: 1347779
Hi

if you get exception at any code then you could place this after the "try". When the "try" starting then all exceptions jump to the code after "except".

Sorry but my english is poor so i don't understand which example you need. Do you need example with TTable ?
Mayby you don't know wher to place the try..except ? If yes then I think so you have code which make the post and you must place the try..except there.
0
 

Author Comment

by:sprawler
ID: 1347780
Hi again .....

An example of an error routine that you have used  or one that you could think up would be fine.  

Lets say that I am trying to enter data into a Table and the field requires an 8 digit number that is a primary key. Instead of typing in 8 digits,  I type in  7 digits. An error is displayed and the program terminates. how woul one program such an EXCEPTION.

Tanx
sprawler





0
 
LVL 3

Expert Comment

by:mirek071497
ID: 1347781
Hi
sorry for the long time.

You must tell me more. Which database (DBF,Paradox ... ) and please submit your fields definition and simple code. I will try to help you.

BTW if you try use exceptions then please not in delphi because then you get always Exception from Delphi not from your proc. So compile program and run without delphi. I remember that you can set this in options, but now i don't know where.
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Can Viruses spread while transferring Binary data with Winsock 2 104
Run video youtube webbrowse 10 85
Drag & Drop... Data from one grid to another 2 51
MS Access from Delphi 31 97
This article explains how to create forms/units independent of other forms/units object names in a delphi project. Have you ever created a form for user input in a Delphi project and then had the need to have that same form in a other Delphi proj…
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
The Email Laundry PDF encryption service allows companies to send confidential encrypted  emails to anybody. The PDF document can also contain attachments that are embedded in the encrypted PDF. The password is randomly generated by The Email Laundr…
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an antispam), the admini…

738 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question