Handling Errors in VB/VBA/VBS/ASP

Real-life Samples

…Or simply put the reusable code appendix.

Get a full file as string to your application

Public Function GetAFile(ByRef TheFile As String) As String
On Error GoTo ErrHandler
Dim F As Integer 

F = FreeFile ' get a free file number (always in the range 1 - 255)
Open TheFile For Binary As #F 'open the file in binary mode
GetAFile = Input(LOF(F), #F)
Close #F ' close the file when your done

Exit Function ' if there was no error, don’t step further than here
ErrHandler: ' this is a named range called ErrHandler

MsgBox "An error happened here!" & vbCrLf & _
"Error number: " & Err.Number & vbCrLf & _
"Error Description" & Err.Description & vbCrLf & _
"Error Help Context ID" & Err.HelpContext & vbCrLf & _
"Error Help File" & Err.HelpFile, vbCritical, "ERROR MESSAGE"

Err.Clear ' destroy the error and…
Resume Next
End Function

Retrieve Error data pertaining to a given error number.

'// Form Code
'Create a form and ad a command button named Command1

Private Sub Command1_Click()
    Call GetErrData(TheNumberHere)
End Sub

'// Module Code

Public Function GetErrData(ByRef ErrorNumber As Long)
On Error GoTo ErrHandler

Err.Raise (ErrorNumber) ' this brief call to the event handler Raises the error

' Note that the Err.Source would be of little help here since
' this would be the calling project that you are in.

Exit Function
MsgBox "This is the error info..." & vbCrLf & _
"Number: " & Err.Number & vbCrLf & _
"Description " & Err.Description & vbCrLf & _
"Help Context ID" & Err.HelpContext & vbCrLf & _
"Help File" & Err.HelpFile, vbCritical, "ERROR MESSAGE"
Err.Clear   ' destroy the error and…
Resume Next
End Function

Get all errors printed to a text file, if a proper description exists

The following function will print out all available errors to a text file called AllErrors.txt in the same location as your application file is stored.

'// Form Code
'Create a form and ad a command button named Command1

Private Sub Command1_Click()
    Call GetAllErrors()
    MsgBox "The Error document has been created", vbExclamation, "Finished!" End Sub

'// Module Code

Public Function GetAllErrors()
'clean out residual error tags
On Error GoTo ErrHandler
Dim I As Long, F As Integer, ErrFile As String
Dim MessageTxt As String

ErrFile = App.Path & "\AllErrors.txt"

F = FreeFile
Open ErrFile For Output As #F
Print #F, "Err.Number|Err.Description|Err.HelpContext|Err.HelpFile"

    For I = 1 To 65535 'all possible valid Long err numbers 'Loop the numbers and call them one by one Err.Raise (I)
' On resuming after getting the error message, go here
'only print the messages clearly defined
If MessageTxt <> "" And _
InStr(1, Trim(MessageTxt), "Application-defined or", vbTextCompare) = 0 Then
    Print #F, MessageTxt
End If

    Next I
Close #F

Exit Function
MessageTxt = Err.Number & "|" & _
Err.Description & "|" & _
Err.HelpContext & "|" & _
Resume GoHere   ' Resume execution at the GoHere line label
End Function

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