Looping through controls (vb.net)

[wild_bill]

I'm new to ASP.NET. I've been asked to convert one of my windows apps into an asp page. I would like to loop through the controls on my page, so I thought using a similar syntax would work, but it doesnt. Here is an example of the code I'm trying to use:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        For Each oControl As Control In Page.Controls
            If TypeOf oControl Is TextBox Then
                Dim txtbox As TextBox = CType(oControl, TextBox)
                txtbox.Text = Date.Now.ToString
            End If
        Next
    End Sub