problem with .dll in aspx page - asp.net-3.5

Question

I have added an assembly to my project and then uses the assembly as follows:
<%# Page Title="" Language="C#" MasterPageFile="~/Global.Master" AutoEventWireup="true" CodeBehind="Calendar.aspx.cs" Inherits="Permias.Calendar" %>
<%# Register TagPrefix="ec" Namespace="ControlSample" Assembly="EventCalendar" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<div id="content">
<div class="post">
<ec:EventCalendar runat="server" ID="eventscalendar" DataSourceID="sqldatasource1"
BorderWidth="0" DayField="starttime" ShowTitle="true" CssClass="eventmonthtable">
<DayHeaderStyle CssClass="caldays" />
<DayStyle CssClass="calcurrentmonth" />
<TodayDayStyle CssClass="calcurrentday" />
<WeekendDayStyle CssClass="calweekend" />
<OtherMonthDayStyle CssClass="calothermonth" />
<DayNumberStyle CssClass="dayNumber" />
<HeaderTemplate>
<table width="100%">
<tr align="center">
<td>
<asp:LinkButton ID="PrevMonth" runat="server" Text='<%# "« " + Container.PrevMonth.ToString("MMMM yyyy") %>'
CommandName="PrevMonth" />
</td>
<td>
<h3>
<asp:Label ID="label2" runat="server" Text='<%# Container.CurrentMonth.ToString("MMMM yyyy") %>' /></h3>
</td>
<td>
<asp:LinkButton ID="NextMonth" runat="server" Text='<%# Container.NextMonth.ToString("MMMM yyyy") + " »" %>'
CommandName="NextMonth" />
</td>
</tr>
</table>
<div class="dashedline">
</div>
</HeaderTemplate>
<DayEventTemplate>
<div style="padding: 3px;">
<asp:HyperLink ID="HyperLink1" runat="server" Text='<%#Eval("title") %>' NavigateUrl='<%# "Events_view.aspx?Eventid=" + Convert.ToString(Eval("ID"))%>'
ToolTip='<%# SharedRoutines.truncate((string)Eval("description")) %>' /></div>
</DayEventTemplate>
</ec:EventCalendar>
</div>
</div>
</div>
</asp:Content>
<asp:Content ID="Content3" ContentPlaceHolderID="splash" runat="server">
<div id="splash"> </div>
</asp:Content>
However it generates an error saying that:
Compiler Error Message: CS0103: The name 'SharedRoutines' does not exist in the current context
Why is this?

Answer 1

You need to include the namespace containing the SharedRoutines class at the top of the page, like this:
<%# Import Namespace="Your.Namespace" %>
You can also include it globally in Web.config:
<pages>
<namespaces>
<add namespace="Your.Namespace" />
</namespaces>
</pages>