Here I am going to explain how to make asp.net dropdownlist with multi select and live search using simple javascript.
define below mentioned javascript in header section
<link rel="stylesheet" href="Content/bootstrap-select.css" />
<script src="Scripts/bootstrap-select.js"></script>
<script src="Scripts/bootbox.min.js"></script>
<asp:DropDownList ID="ddlsearch" runat="server" CssClass="selectpicker show-tick" data-live-search="true">
<asp:ListItem Text="A" Value="A"></asp:ListItem>
</asp:DropDownList>
For data live search data-live-search="true"
For multi select just enter (multiple)
I hope this will help you, if you have any query please revert.
