How to get all items when client enter % in autocomplete

Hi,

ref my below code, this woks well, here I want to add one more option, when client type % symbol then items need to display in the txt_SubCategory textbox, kindly help me how to do that.

 $(function () {
                $('[id*=txt_SubCategory]').typeahead({
                    hint: true,
                    highlight: true,
                    minLength: 1,
                    source: function (request, response) {
                        if ($("#ddl_TicketCategory").val() == 0) {
                            $('#ddl_TicketCategory').css('border-color', 'red');
                            alert('Sorry!\nPlease Select a Primary Category Iteam!');
                            return false;
                        } else {
                            var categoryID = $('#ddl_TicketCategory').val();
                            $('#ddl_TicketCategory').css('border-color', 'blue');
                        }
                        $.ajax({
                            url: '<%=ResolveUrl("~/RegisterUser.aspx/Get_SubCategory") %>',
                            data: JSON.stringify({ 'prefix': request, 'categoryID': categoryID }),
                            dataType: "json",
                            type: "POST",
                            contentType: "application/json; charset=utf-8",
                            success: function (data) {
                                items = [];
                                map = {};
                                $.each(data.d, function (i, item) {
                                    var id = item.split('-')[1];
                                    var name = item.split('-')[0];
                                    map[name] = { id: id, name: name };
                                    items.push(name);
                                });
                                response(items);
                                $(".dropdown-menu").css("height", "auto");
                                $(".dropdown-menu").css("background-color", "#D3D3D3");
                            
                            },
                            error: function (response) {

                                alert(response.responseText);
                            },
                            failure: function (response) {
                                alert(response.responseText);
                            }
                        });
                    },
                    updater: function (item) {
                        $('[id*=hfSubCatgr]').val(map[item].id);
                        return item;
                    }
                });
            });



<WebMethod()>
    Public Shared Function Get_SubCategory(ByVal prefix As String, ByVal categoryID As String) As String()
        Dim CatgSubItem As New List(Of String)()
        Using conn As New SqlConnection()
            conn.ConnectionString = ConfigurationManager.ConnectionStrings("ICT_ConStr").ConnectionString
            Using cmd As New SqlCommand()
                cmd.CommandText = "SELECT DISTINCT [SubCategoryID],[SubCategoryName] FROM [dbo].[Category] Where [MasterCategoryID]=" & categoryID & " AND [SubCategoryName] like @SearchText + '%' "
                cmd.Parameters.AddWithValue("@SearchText", prefix)
                cmd.Connection = conn
                conn.Open()
                Using sdr As SqlDataReader = cmd.ExecuteReader()
                    While sdr.Read()
                        CatgSubItem.Add(String.Format("{0}-{1}", sdr("SubCategoryName"), sdr("SubCategoryID")))
                    End While
                End Using
                conn.Close()
            End Using
        End Using
        Return CatgSubItem.ToArray()
    End Function