VB6.0:Tutorial, Error handling

**TcM** · 10-15-2006, 02:36 AM

Introduction:-
Ok So I decided to make a tutorial about error handling! Many programs don't contain error handling but I suggest you that you include it! This will make your program more powerful

Solution:-
Ok so I am going to show you this code then I will expalin it. I will show you 3 types of error handling

What you need:-

3 Command buttons

Some time

Here is the code

Code:

Private Sub Command1_Click()
On Error GoTo ErrorHandler
Error 424 'This error is displayed when there is a missing object
Exit Sub
ErrorHandler:
MsgBox "Error Number: " & Err.Number & " With The Description ->> " & Err.Description & " <<- Occured."
End Sub

Private Sub Command2_Click()
On Error GoTo ErrorHandler
Error 424
Exit Sub
ErrorHandler:
If Err.Number = 424 Then
MsgBox "A missing object in your form is needed!, Please refer to the code and arrange accordingly!"
Else: MsgBox "Error Number: " & Err.Number & " With The Description ->> " & Err.Description & " <<- Occured."
End If
End Sub

Private Sub Command3_Click()
On Error Resume Next
Error 424 'This error is displayed when there is a missing object
MsgBox "error ignored!"
End Sub

Explanation:-

Code:

On Error GoTo ErrorHandler

This will tell the program that when an error is found it will call the 'chunk' of code named ErrorHandler ( you will see it in a while )

Code:

Error 424 'This error is displayed when there is a missing object
Exit Sub

This will generate an error, instead of this code you will have your code here, I just made that for an error to be generated so DON'T include that in your program this is just for testing purposes!!! and the 2nd line is there so to IF no error occurs the 'chunk' of code named ErrorHandler will not be executed

[code]
ErrorHandler:
MsgBox "Error Number: " & Err.Number & " With The Description ->> " & Err.Description & " <<- Occured."
End Sub
[code]
This will be the action that will be done when an error occurs it will show you the error number and the description!

Code:

ErrorHandler:
If Err.Number = 424 Then
MsgBox "A missing object in your form is needed!, Please refer to the code and arrange accordingly!"
Else: MsgBox "Error Number: " & Err.Number & " With The Description ->> " & Err.Description & " <<- Occured."
End If

This will be found on the Command2 event instead this type of error handling is when the programmer knows for example that when something is done the error will popup so he should make this type of error handling so not to let his program crash. here I edded IF .... THEN.... ELSE so IF the error number is 424 THEN it will do something or if not ELSE it will show the first method

Code:

On Error Resume Next
Error 424 'This error is displayed when there is a missing object
MsgBox "error ignored!"

Here we are telling the program to just IGNORE the error and continue the next action ( in this case show a msg box )

Conclusion:-
As Always Feedback is welcome and the full source is attached!!