GanttView.RequestTimescaleRulers Event

Occurs when timescale rulers are visually changed and allows you to edit timescale rulers. This is a routed event.

Namespace: DevExpress.Xpf.Gantt

Assembly: DevExpress.Xpf.Gantt.v23.2.dll

NuGet Package: DevExpress.Wpf.Gantt

Declaration

C#

public event EventHandler<RequestTimescaleRulersEventArgs> RequestTimescaleRulers

VB.NET

Public Event RequestTimescaleRulers As EventHandler(Of RequestTimescaleRulersEventArgs)

Event Data

The RequestTimescaleRulers event's data class is RequestTimescaleRulersEventArgs. The following properties provide information specific to this event:

Property	Description
Handled	Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
NonworkingDayVisibility	Gets or sets the nonworking day visibility at a current zoom level.
NonworkingTimeVisibility	Gets or sets the nonworking time visibility at a current zoom level.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
TimescaleRulers	Get or sets a collection of timescale rulers displayed at the current zoom level.
Zoom	Gets the current zoom.

The event data class exposes the following methods:

Method	Description
InvokeEventHandler(Delegate, Object)	When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)	When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.

Remarks

The RequestTimescaleRulers event occurs on init, when the Gantt area is zoomed and when the TimescaleRulerCount property value is changed.

Handle the RequestTimescaleRulers event to dynamically change the following:

• a set of rulers displayed within the timescales (RequestTimescaleRulersEventArgs.TimescaleRulers)
• visibility of nonworking days and nonworking time (RequestTimescaleRulersEventArgs.NonworkingDayVisibility and RequestTimescaleRulersEventArgs.NonworkingTimeVisibility)

C#

private void view_RequestTimescaleRulers(object sender, DevExpress.Xpf.Gantt.RequestTimescaleRulersEventArgs e) {
    // Remove a ruler from timescale
    e.TimescaleRulers.RemoveAt(1);
    // Add a ruler that indicates hours
    e.TimescaleRulers.Add(new DevExpress.Xpf.Gantt.TimescaleRuler(DevExpress.Xpf.Gantt.TimescaleUnit.Hour));
    // Add a ruler that indicates 30 minute ranges
    e.TimescaleRulers.Add(new DevExpress.Xpf.Gantt.TimescaleRuler(DevExpress.Xpf.Gantt.TimescaleUnit.Minute, 30));

    // Nonworking dates and nonworking time are not indicated with a specific background
    e.NonworkingDayVisibility = Visibility.Hidden;
    e.NonworkingTimeVisibility = Visibility.Hidden;
}

VB.NET

Private Sub view_RequestTimescaleRulers(ByVal sender As Object, ByVal e As DevExpress.Xpf.Gantt.RequestTimescaleRulersEventArgs)
    ' Remove a ruler from timescale
    e.TimescaleRulers.RemoveAt(1)
    ' Add a ruler that indicates hours
    e.TimescaleRulers.Add(New DevExpress.Xpf.Gantt.TimescaleRuler(DevExpress.Xpf.Gantt.TimescaleUnit.Hour))
    '  Add a ruler that indicates 30 minute ranges
    e.TimescaleRulers.Add(New DevExpress.Xpf.Gantt.TimescaleRuler(DevExpress.Xpf.Gantt.TimescaleUnit.Minute, 30))

    ' Nonworking dates and nonworking time are not indicated with a specific background
    e.NonworkingDayVisibility = Visibility.Hidden
    e.NonworkingTimeVisibility = Visibility.Hidden
End Sub

The RequestTimescaleRulers event allows you to add timescale rulers with custom formats:

1. Create a class that implements IFormatProvider and ICustomFormatter interfaces.

2. In this class, specify the ruler’s text and format. The following code sample displays months or two-month ranges based on the zoom level:

   C#

   public class CustomFormatProvider : IFormatProvider, ICustomFormatter {
       public static CustomFormatProvider GetFormatProvider(TimeSpan zoom) {
           return new CustomFormatProvider(zoom.Hours > 2 ? "{0:MMM}" : "{0:MMMM yyyy} - {1:MMMM yyyy}");
       }
   
       public string FormatString { get; }
   
       public CustomFormatProvider(string formatString) {
           FormatString = formatString;
       }
       public object GetFormat(Type formatType) {
           if (typeof(ICustomFormatter) == formatType)
               return this;
           else
               return null;
       }
       public string Format(string format, object arg, IFormatProvider formatProvider) {
           var range = arg as DateTimeRange?;
           return range.HasValue ? string.Format(FormatString, range.Value.Start, range.Value.End) : null;
       }
   }
   

   VB.NET

   Public Class CustomFormatProvider
       Implements IFormatProvider, ICustomFormatter
   
       Public Shared Function GetFormatProvider(ByVal zoom As TimeSpan) As CustomFormatProvider
           Return New CustomFormatProvider(If(zoom.Hours > 2, "{0:MMM}", "{0:MMMM yyyy} - {1:MMMM yyyy}"))
       End Function
   
       Public ReadOnly Property FormatString As String
   
       Public Sub New(ByVal formatString As String)
           Me.FormatString = formatString
       End Sub
   
       Public Function GetFormat(ByVal formatType As Type) As Object Implements IFormatProvider.GetFormat
           If GetType(ICustomFormatter) Is formatType Then
               Return Me
           Else
               Return Nothing
           End If
       End Function
   
       Public Function Format(ByVal pFormat As String, ByVal arg As Object, ByVal formatProvider As IFormatProvider) As String Implements ICustomFormatter.Format
           Dim range = CType(arg, DateTimeRange?)
           Return If(range.HasValue, String.Format(FormatString, range.Value.Start, range.Value.End), Nothing)
       End Function
   End Class
   

3. Add a new timescale ruler and pass your custom format to its FormatProvider property:

   C#

   private void RequestTimescaleRulers(object sender, RequestTimescaleRulersEventArgs e) {
       e.TimescaleRulers.Clear();
       e.TimescaleRulers.Add(
           new TimescaleRuler(TimescaleUnit.Month, 
           formatProvider: CustomFormatProvider.GetFormatProvider(ganttView.Zoom))
       );
   }
   

   VB.NET

   Private Sub RequestTimescaleRulers(ByVal sender As Object, ByVal e As RequestTimescaleRulersEventArgs)
       e.TimescaleRulers.Clear()
       e.TimescaleRulers.Add(New TimescaleRuler(TimescaleUnit.Month, formatProvider:=CustomFormatProvider.GetFormatProvider(Me.ganttView.Zoom)))
   End Sub