How to add ScrollBar to ASP.Net DropDownList using CSS

Please refer this

http://forums.asp.net/t/1905270.aspx?DropDownList+Scroll+Bars

http://stackoverflow.com/questions/21948198/how-to-add-scroll-bar-on-dropdownlist-in-asp-net

Thank You.

The following should solve your problem

    <style type="text/css">
        #DDLcity1
        {
            width: 128px;
            margin: 0 15px 0 0;
            font: 12px tahoma;
            direction: rtl;
            max-height: 200px;
            overflow-y: scroll;
            position: relative;           
        }
    </style>
    <asp:DropDownList ID="DDLcity1" runat="server" CssClass="DDlcityE" ForeColor="#ca0202"
            onmousedown="this.size=5;" onfocusout="this.size=1;" ondblclick="this.size=1;"
            AppendDataBoundItems="True" AutoPostBack="true">
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
            <asp:ListItem Text="Test"></asp:ListItem>
        </asp:DropDownList>