Third DDL only populates Textbox with Index of 1

[bubberz]

I have three dropdownlists, and the third is dependant on the selections of the first two ddls.

If I try to assign a Textbox's value to this third ddl,

Private Sub ddlResource_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlResource.SelectedIndexChanged
txtResource.Text = ddlResource.SelectedItem.ToString()
End Sub

and I select something like the 10th or 11th record, it always shows as the first record value.

I do have "PostBack"=true for this third ddl, and this ddl is populated in the Private Sub Page_PreRender handler