Problem with global variables

I have a problem with global variables on my webpage.
Partial Class nieuwc

Inherits System.Web.UI.Page

Private iev As String

Private sitev As String

Private kaslv As String

Private klantv As String



Protected Sub ieb_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles ieb.Click

iev = Me.ie.SelectedValue

Me.label.Text = "Extern/Intern: " & iev

End Sub

Protected Sub siteb_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles siteb.Click

sitev = Me.site.SelectedValue

Me.label.Text &= "<br />Site: " & sitevDim kl as new klClass

Me.kasl.DataSource = kl.getSL(iev)

Me.kasl.DataBind()

End Sub


End Class

 

When clicking on the Button "ieb", the selected value of Dropdownlist "ie" is successfully stored in gl ...