Login | Register   
RSS Feed
Download our iPhone app
Browse DevX
Sign up for e-mail newsletters from DevX

By submitting your information, you agree that devx.com may send you DevX offers via email, phone and text message, as well as email offers about other products and services that DevX believes may be of interest to you. DevX will process your information in accordance with the Quinstreet Privacy Policy.

Tip of the Day
Language: Visual Basic
Expertise: Beginner
Jun 15, 1999



Application Security Testing: An Integral Part of DevOps

Working With Collections

When working with collections, use an error handler to easily determine if a given key exists in the collection. If you try to access an item from a collection where the key doesn't exist, you'll get an error. Likewise, if you try to add an item that exists, you'll also get an error. This example shows an error handler for adding an item to a collection. To trap for errors where an item exists, trap error code 457:

Private Function BuildCustCol(CustList As ListBox) As _
	On Error GoTo ProcError
	Dim colCust As Collection
	Dim lngCustCnt As Long
	Dim J As Long

	Set colCust = New Collection
	For J = 0 To CustList.ListCount - 1
		lngCustCnt = colCust(CStr(CustList.List(J))) + 1
		colCust.Remove (CStr(CustList.List(J)))
		colCust.Add Item:=lngCustCnt, _
	Next J
	Set BuildCustCol = colCust
	Set colCust = Nothing
	Exit Function

	Select Case Err
		Case 5 'collection item doesn't exist, so add it
			colCust.Add Item:=0, _
		Case Else
		'untrapped error
	End Select

End Function
Joe Karbowski
Comment and Contribute






(Maximum characters: 1200). You have 1200 characters left.



Thanks for your registration, follow us on our social networks to keep up-to-date