You should override the getTemplateEventData of MonthView.
Example
<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Ext.NET Example</title>
<ext:ResourcePlaceHolder runat="server" Mode="ScriptFiles" />
<script type="text/javascript">
Ext.calendar.MonthView.override({
getTemplateEventData: function(evt) {
var M = Ext.calendar.EventMappings,
selector = this.getEventSelectorCls(evt[M.EventId.name]),
title = evt[M.Title.name];
return Ext.applyIf({
_selectorCls: selector,
_colorCls: 'ext-color-' + (evt[M.CalendarId.name] ?
evt[M.CalendarId.name] : 'default') + (evt._renderAsAllDay ? '-ad': ''),
_elId: selector + '-' + evt._weekIndex,
_isRecurring: evt.Recurrence && evt.Recurrence != '',
_isReminder: evt[M.Reminder.name] && evt[M.Reminder.name] != '',
//original: Title: (evt[M.IsAllDay.name] ? '': evt[M.StartDate.name].format('g:ia ')) + (!title || title.length == 0 ? '(No title)': title)
Title: (evt[M.IsAllDay.name] ? '': (!title || title.length == 0 ? '(No title)': title))
},
evt);
}
});
</script>
</head>
<body>
<form runat="server">
<ext:ResourceManager runat="server" />
<ext:Viewport runat="server" Layout="FitLayout">
<Items>
<ext:CalendarPanel ID="CalendarPanel1" runat="server">
<EventStore runat="server">
<Events>
<ext:Event
Title="My event"
StartDate="2012/3/15"
EndDate="2012/3/16"
CalendarId="1" />
</Events>
</EventStore>
</ext:CalendarPanel>
</Items>
</ext:Viewport>
</form>
</body>
</html>