Applying a time offset to a time-aware feature layer
TimeOffsetButton.vb
' Copyright 2012 ESRI
' 
' All rights reserved under the copyright laws of the United States
' and applicable international laws, treaties, and conventions.
' 
' You may freely redistribute and use this sample code, with or
' without modification, provided you include the original copyright
' notice and use restrictions.
' 
' See the use restrictions.
' 

Imports System.Windows.Forms
Imports ESRI.ArcGIS.ArcMapUI
Imports ESRI.ArcGIS.Framework
Imports ESRI.ArcGIS.Carto
Imports ESRI.ArcGIS.esriSystem
Imports ESRI.ArcGIS.Display

Public Class TimeOffsetButton
  Inherits ESRI.ArcGIS.Desktop.AddIns.Button

  Public Sub New()

  End Sub

  Protected Overrides Sub OnClick()
    Dim pMxDoc As IMxDocument = My.ArcMap.Document
    Dim pMap As IMap = pMxDoc.FocusMap
    Dim filename As String = "TimeAwareHurricanes.mxd"

    If pMap.LayerCount < 1 Then
      MessageBox.Show("Before running this sample, load the associated file '" & filename & "'")
      Return
    End If
    If pMap.Layer(0).Name <> "atlantic_hurricanes_2000" Then
      MessageBox.Show("Before running this sample, load the associated file '" & filename & "'")
      Return
    End If
    Dim selectedLayer As ILayer = My.ArcMap.Document.SelectedLayer
    If selectedLayer Is Nothing Then
      MessageBox.Show("There is no selected layer.  Select a time-aware layer")
      Return
    End If

    Dim pTZFac As ITimeZoneFactory = New TimeZoneFactoryClass()
    Dim pFLyr As IFeatureLayer = TryCast(selectedLayer, IFeatureLayer)
    Dim pTimeData As ITimeData = TryCast(pFLyr, ITimeData)

        'making the first layer of the focused map time-aware
    If pTimeData.SupportsTime Then
      pTimeData.UseTime = True
      Dim pTimeAnimProp As ITimeDataDisplay = TryCast(pFLyr, ITimeDataDisplay)
      pTimeAnimProp.TimeOffsetUnits = ESRI.ArcGIS.esriSystem.esriTimeUnits.esriTimeUnitsYears
      pTimeAnimProp.TimeOffset = System.DateTime.Now.Year - 2000
    Else
      MessageBox.Show("Before running this sample, load the associated file '" & filename & "'")
      Return
    End If

    Dim pActiveView As IActiveView = TryCast(pMap, IActiveView)
    pActiveView.Refresh()
  End Sub

  Protected Overrides Sub OnUpdate()
    Enabled = True
  End Sub
End Class