IsPrimaryInterval Property

using System.Collections.Generic;
using Infragistics.Win;
using Infragistics.Win.UltraWinSchedule;
using System.Diagnostics;

    public void ShowClocks( UltraTimelineView control )
    {
        //  Don't show any additional intervals
        control.AdditionalIntervals.Clear();

        //  Create a new TimeInterval with 15-minute intervals
        //  and assign it to the PrimaryInterval property.
        TimeInterval primaryInterval = new TimeInterval(15, TimeIntervalUnits.Minutes);
        control.PrimaryInterval = primaryInterval;

        //  Set the image alignment to middle/center
        control.ColumnHeaderAppearance.ImageHAlign = HAlign.Center;
        control.ColumnHeaderAppearance.ImageVAlign = VAlign.Middle;

        //  Set ColumnHeaderImageSize to a size that is large
        //  enough to display an analog clock image; set the
        //  ColumnWidth property to a slightly larger size,
        //  and set MinimumColumnResizeWidth as well so the user
        //  can't resize the headers any smaller than that size.
        control.ColumnHeaderImageSize = ClockSize;
        control.ColumnWidth = ClockSize.Width + Padding;
        control.MinimumColumnResizeWidth = control.ColumnWidth;

        //  Handle the ColumnHeaderInitializing event so we can
        //  show an image on the header instead of the text, and
        //  the ColumnHeaderToolTipDisplaying event so we can force
        //  a tooltip to be displayed.
        control.ColumnHeaderInitializing += new ColumnHeaderInitializingHandler(this.OnColumnHeaderInitializing);
        control.ColumnHeaderToolTipDisplaying += new ColumnHeaderToolTipDisplayingHandler(OnColumnHeaderToolTipDisplaying);
    }

    private void OnColumnHeaderToolTipDisplaying(object sender, ColumnHeaderToolTipDisplayingEventArgs e)
    {
        //  If this is a primary interval header, show the start time
        //  in a tooltip, since there is no text on the header.
        if ( e.HeaderElement != null && e.HeaderElement.DateTimeInterval.IsPrimaryInterval )
        {
            ToolTipInfo toolTipInfo = e.ToolTipInfo;
            toolTipInfo.ToolTipText = e.HeaderElement.DateTimeRange.StartDateTime.ToString(TimeInterval.ShortTimePattern);
            e.ToolTipInfo = toolTipInfo;
        }
    }

    private void OnColumnHeaderInitializing(object sender, ColumnHeaderInitializingEventArgs e)
    {
        if ( e.DateTimeInterval.IsPrimaryInterval )
        {
            //  Create an image of an analog clock, depicting the
            //  start time for this header, and assign it to the
            //  Image property of the e.AppearanceData
            TimeSpan time = e.DateTimeRange.StartDateTime.TimeOfDay;
            Bitmap bmp = ClockImage.GetImage( time, ClockSize, Color.Black, Color.White );
            AppearanceData appData = new AppearanceData();
            appData.Image = bmp;
            e.AppearanceData = appData;

            //  Assign a space character to the text, so that
            //  nothing appears, but a tooltip can still be displayed
            e.Text = " ";
        }
    }