Mastering PowerBuilder

By default, PFC displays the error message and stops the application, irrespective of the user response. For example, if you display Abort, Ignore buttons and the user clicks on the "Ignore" button, the application still stops instead of continuation. This is because, PFC is not trapping the user’s response, instead, it’s blindly halting the application. You can see this code in the pfc_n_cst_AppManager’s pfc_SystemError event.

What we need to do is, override this event in the "n_cst_AppManager". If you want to use the existing code, just copy the code from the ancestor into the descendant’s event. Change the following line of code:

inv_error.of_message('pfc_systemerror', ls_msgparm)

to trap the return code of the function, as shown below:

li_rc = inv_error.of_message('pfc_systemerror', ls_msgparm)

Act depending on the function return code as shown below. The function returns the number of the button the user clicked. ( Starts from 1 from left. )

If li_rc = 1 Then
   this.event pfc_exit()
Else
   Return
End If

The above code is just an example. Just by knowing the clicked button number, you can’t act, because, you really don’t know the meaning of the button. For example, return code 2 would mean "No" in the "YesNoCancel" and "Retry" in the "AbortRetryIgnore". How do you know which one of these buttons are used to the message in the database? If you are using the same icons for any error throughout the application, then it’s easy to code. If your application is using different icons depending on the error, then you can call the of_Message() function with all the parameters. This function is overloaded and has many flavors. If you use the following format, you know which icon the user clicked exactly.

li_rc = inv_Error.of_Message( "Title", &
        "Message", StopSign!, &
            AbortRetryIgnore!, 1, 5, TRUE, TRUE )

The function of_message() at the pfc_n_cst_error object is overloaded. One flavor of that function takes a string array as the second parameter. For example, if you have defined an error message with three parameters, then you can declare an unbound string array and load the parameters into the array and send the array to the function:

ls_msgparm[1] = "Parameter 1"
ls_msgparm[2] = "Parameter 2"
ls_msgparm[3] = "Parameter 3"
li_rc = inv_error.of_message('pfc_systemerror', ls_msgparm)

PFC takes care of placing the parameters into correct positions in the error message, first parameter will replace the first occurrence of %s and the second parameter with the second occurrence of %s, and so on.