可输入的下拉菜单

借鉴别人的改了一下~
HTML:

<style>
    .dropdownlist { MARGIN-LEFT: -100px; WIDTH: 118px }
</style>

<div style="POSITION:relative">
                <SPAN style="MARGIN-LEFT: 100px; OVERFLOW: hidden; WIDTH: 18px">
                    <asp:dropdownlist id="DropDownList1" runat="server" CssClass="dropdownlist" AutoPostBack="True">
                        <asp:ListItem Value="1">横线</asp:ListItem>
                        <asp:ListItem Value="2">竖线</asp:ListItem>
                    </asp:dropdownlist>
                </SPAN>
                <INPUT style="LEFT: 0px; WIDTH: 100px; POSITION: absolute" size="11" name="box2" id="Text1"
                    runat="server">
    </div>

后台:

private void DropDownList1_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            this.Text1.Value = this.DropDownListArcClass.SelectedItem.Text;
        }

一定还有更好的办法~

来源：https://www.cnblogs.com/avril2005/archive/2005/04/27/146291.html