The errors can be automatically managed by WINDEV. This feature helps you reduce the number of code lines while centralizing the management of errors.

The use of this feature also makes the code easier to read.

Operating mode

Two operations are performed when an error is detected by a WLanguage function:

an error value is returned by the function (for example, fOpen returns "-1" if the specified file was not opened).
WLanguage detects the error (the ErrorOccurred variable is set to True), and its details can be retrieved using ErrorInfo.

This second operation can be automatically managed by the error management of WINDEV.

Implementation

The automatic management of errors can be configured:

in the code editor: all you have to do is click the link "If error: By program" in the code editor:
by programming with ErrorChangeParameter.

Types of affected errors

Two types of errors can occur in WLanguage:

the "non-fatal" errors (also called runtime errors): in most cases, these errors are managed in the code and they do not stop the application. For example, opening a file that cannot be accessed or an archive that does not exist.
the "fatal" errors (also called programming errors): in most cases, these errors are linked to a development problem (access to a non-declared file, use of non-existing controls ...). A "fatal" error can also occur after a "non-fatal" error that was not processed properly. In this case, the application will be stopped.

The mechanism for managing errors is used to manage these two types of errors according to different methods in order to specify behaviors adapted to the errors that occur.

Automatic management of errors: a training example

To understand the different error cases, we will be using a training example supplied with WINDEV.
1. Display the WINDEV home page if necessary (Ctrl + <).
2. On the home page, click "Open an example". The list of complete examples, training examples and unit examples supplied with WINDEV is displayed.
3. Type "Error" in the search area. Only the examples containing this word are listed.
4. Select the "WD Auto Error Management" project. The project is loaded.

This project presents the management:
- of a non-fatal error (opening an archive that does not exist).
- of a fatal error (division by 0).
- of an error on several levels.

Run the project test by clicking (among the quick access buttons).
1. Click "Managing a non-fatal error".
2. The following window is displayed.
3. Click the "Test this error management" button.
4. When running the code line that triggers the error, an error message is displayed, allowing the user to retry the operation, cancel the operation or stop the application. The "Debug" option should be used:
  - in test mode, to directly debug the application.
  - in executable mode, to debug an executable directly from WINDEV.
5. Click "Cancel the operation" and close the window.

Click "Managing a fatal error".
1. The following window is displayed. This window is used to check the error when an integer is divided by 0.
2. Click the "Test this error management" button.
3. When running the code line that triggers the error, a procedure is automatically called. This procedure is used to display the error message and to stop the current process.
4. Click "OK" and close the window.

Click "Managing an error on several levels".
1. The following window is displayed. This window is used to test an error on several levels (process calling a procedure that opens an archive that does not exist).
2. Click the "Test this error management" button.
3. When running the code line that triggers the error:
  - the procedure returns "False" to the calling process.
  - the calling process displays an error message and stops the process.
4. Click the "Cancel the operation" button.

Stop the application test.


	Example	WINDEV also proposes an automatic management of HFSQL errors. See the "Detecting HFSQL errors" training example (supplied with WINDEV) for more details. This example is accessible from the WINDEV home page.

Páginas

sábado, 29 de agosto de 2020

DICAS 3059 -WINDEV TUTORIAL 82 -Licao 7.2-05-09-2020 11hrs-GERENCIAMENTO AUTOMATICO ERROS

https://youtu.be/41J0TqQjK3k

Esse Ao Vivo vai estrear as 11:00 do dia 05/09/2020

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