Custom Interval Types

RadTimeline 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 RadTimeline 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 RadTimeline control:

• XAML

<telerik:RadTimeline PeriodStart="2011-01-01" 
                     PeriodEnd="2012-01-01"> 
    <telerik:RadTimeline.Intervals> 
        <example:CustomInterval /> 
        <telerik:MonthInterval /> 
    </telerik:RadTimeline.Intervals> 
</telerik:RadTimeline> 

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:

• C#
• VB.NET

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 
    { 
        get 
        { 
            return formatters; 
        } 
    } 
 
    public override TimeSpan MinimumPeriodLength 
    { 
        get 
        { 
            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)() 
        Get 
            Return m_formatters 
        End Get 
    End Property 
 
    Public Overrides ReadOnly Property MinimumPeriodLength() As TimeSpan 
        Get 
            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 

Find a runnable project of the previous example in the WPF Samples GitHub repository.

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