HyperLink: perchè non va?

[Daniele80]

ciao a tutti,
io dichiaro nella mia classe un placeholder

poi dentro ad una SUB mi creo un HyperLink, lo setto e lo passo al mio placeholder.

Protected WithEvents btn_Next As System.Web.UI.WebControls.PlaceHolder

Dim btnNext As HyperLink
btnNext.ImageUrl = "images\bottoni\bottnext.gif"
 btnNext.NavigateUrl = "lista.aspx?cat=" & cat.Replace(" '", "''") & "&p=" & CurrentPage + 1
btn_Next.Controls.Add(btnNext)

però ricevo questo errore:

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

su questa riga:
btnNext.ImageUrl = "images\bottoni\bottnext.gif"

[Daniele80]

l'errore stava qui:
Dim btnNext As HyperLink

la correzione è questa:
Dim btnNext As New HyperLink