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[code=HTML] <asp:DropDownList   ID= "DropDownList1 "   runat= "server "   DataSourceID= "SqlDataSource2 "
                        DataTextField= "Type "   DataValueField= "Type "     OnTextChanged= "DropDownList1_SelectedIndexChanged "   OnDataBound= "DropDownList1_DataBound "     AutoPostBack= "True "   > [/code]
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[code=HTML] <script   type= "text/C# "   language= "jscript ">
function   Hide_A(){
        A.style.display= "none ";
}
</script> [/code]
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[code=CS]protected   void   DropDownList1_DataBound(object   sender,   EventArgs   e)
        {
                if   (DropDownList1.SelectedIndex   ==   -1)
                {
                        this.Last.Visible   =   false;