DropDownList.SelectedValue Problem

I am setting my dropdownlist.selectedvalue on page load. 
My problem is that when I try to get the value after the user clicks a button, the value is still what I set it to previously on the inital page load.  

I check that the page is not a postback when I set the value, so after the user clicks the button, the page should not reset it to the initial

If Not Page.IsPostBack Then
  me.ddl.selectedvalue = 1
End If

I've run into this problem several times and don't know if I'm doing something wrong or what, but it's a big stumbling block for me right now.

Any help is appreciated. 

Thank you,

Mike
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