Hi
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
onselectedindexchanged="DropDownList1_SelectedIndexChanged">
<asp:ListItem>AUDUSE</asp:ListItem>
<asp:ListItem>USDASD </asp:ListItem>
</asp:DropDownList>
code:
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
string a = DropDownList1.SelectedItem.Text.Substring(0,3);
int length = (DropDownList1.SelectedItem.Text.Length) - 3;
string b = DropDownList1.SelectedItem.Text.Substring(3,length);
}