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Custom Interval Types

RadTimeBar provides built-in support for a couple of predefined interval types ranging from milliseconds to centuries. For a full list of the predefined intervals, please refer to the Interval Formatters article. For all custom scenarios that the predefined intervals do not cover, the control supports custom interval type implementations.

Using Custom Interval Types

The Intervals collection contains items of type IntervalBase. That is why, in order to configure a RadTimeBar control to use a custom interval type, simply add an instance of that custom interval to the Intervals collection of the control.

The example below shows how you can add a custom interval type to the Intervals collection of a RadTimeBar control:

<telerik:RadTimeBar PeriodStart="2011-01-01"
        <example:CustomInterval />
        <telerik:MonthInterval />

The IntervalBase class

A custom interval is a class that inherits the IntervalBase class and implements its abstract properties and methods:

  • Formatters – Gets a collection of formatter that the interval can use to convert DateTime objects to strings.
  • MinimumPeriodLength - Gets the smallest interval period.
  • ExtractIntervalStart – Given a DateTime object, this method returns the start of the interval that contains the given DateTime object.
  • IncrementByInterval – Given a DateTime object and span, this method increments the specified DateTime object by the specified number of MinimumPeriodLengths

Below you can find a sample custom interval implementation:

using Telerik.Windows.Controls.TimeBar;
public class CustomInterval : IntervalBase
    private static readonly Func<DateTime, string>[] formatters;

    static CustomInterval()
        formatters = new Func<DateTime, string>[]
            date => string.Format("My custom interval {0}, {1}", GetNumberOfInterval(date), date.ToString("yyyy")),
            date => string.Format("Custom interval {0}", GetNumberOfInterval(date)),
            date => string.Format("C{0} {1}", GetNumberOfInterval(date), date.ToString("yyyy")),

    public override DateTime ExtractIntervalStart(DateTime date)
        int firstMonthOfInterval = GetFirstMonthOfInterval(date);
        return new DateTime(date.Year, firstMonthOfInterval, 1);

    public override DateTime IncrementByInterval(DateTime date, int intervalSpan)
        return date.AddMonths(intervalSpan * 6);

    public override Func<DateTime, string>[] Formatters
            return formatters;

    public override TimeSpan MinimumPeriodLength
            return TimeSpan.FromDays(180);

    private static int GetNumberOfInterval(DateTime date)
        int number = ((date.Month - 1) / 6) + 1;
        return number;

    private int GetFirstMonthOfInterval(DateTime date)
        int quarter = GetNumberOfInterval(date);
        int firstMonthOfInterval = ((quarter - 1) * 6) + 1;
        return firstMonthOfInterval;
Imports Telerik.Windows.Controls.TimeBar
Public Class CustomInterval
    Inherits IntervalBase
    Private Shared ReadOnly m_formatters As Func(Of DateTime, String)()

    Shared Sub New()
        m_formatters = New Func(Of DateTime, String)() {Function([date]) String.Format("My custom interval {0}, {1}", GetNumberOfInterval([date]), [date].ToString("yyyy")), Function([date]) String.Format("Custom interval {0}", GetNumberOfInterval([date])), Function([date]) String.Format("C{0} {1}", GetNumberOfInterval([date]), [date].ToString("yyyy"))}
    End Sub

    Public Overrides Function ExtractIntervalStart([date] As DateTime) As DateTime
        Dim firstMonthOfInterval As Integer = GetFirstMonthOfInterval([date])
        Return New DateTime([date].Year, firstMonthOfInterval, 1)
    End Function

    Public Overrides Function IncrementByInterval([date] As DateTime, intervalSpan As Integer) As DateTime
        Return [date].AddMonths(intervalSpan * 6)
    End Function

    Public Overrides ReadOnly Property Formatters() As Func(Of DateTime, String)()
            Return m_formatters
        End Get
    End Property

    Public Overrides ReadOnly Property MinimumPeriodLength() As TimeSpan
            Return TimeSpan.FromDays(180)
        End Get
    End Property

    Private Shared Function GetNumberOfInterval([date] As DateTime) As Integer
        Dim number As Integer = (([date].Month - 1) / 6) + 1
        Return number
    End Function

    Private Function GetFirstMonthOfInterval([date] As DateTime) As Integer
        Dim quarter As Integer = GetNumberOfInterval([date])
        Dim firstMonthOfInterval As Integer = ((quarter - 1) * 6) + 1
        Return firstMonthOfInterval
    End Function
End Class

You can download a runnable project of the demonstrated example from our online SDK repository here, after navigating to TimeBar/CustomIntervalTypes.

Using the sample custom interval above, you will get the following result:

See Also

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