Generate code in ASP.Net using response.write

I have made the label below using response.write.

Code:

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dim i as integer
for i = 1 to 10
  response.write("<asp:label id='Label99" & i & "' runat='server'>&nbsp;<b>Test" & i & "</b></asp:label>")
next

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And this works fine.
But if I wish to change the text of the label using a button I can't make it work, nothing happens. Isn't this possible? Otherwise I think it's impossible to make some automated code generation in ASP.Net.

Code:

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Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim label991 As New Label()
        Label991.Text = "HPL"
    End Sub

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