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CacheDependency::UtcLastModified Property
Visual Studio 2010
Gets the time when the dependency was last changed.
Assembly: System.Web (in System.Web.dll)
The following code example uses the AggregateCacheDependency class to add an item, with two CacheDependency object dependencies, to the Cache. When a request for the Cache item is made, the code checks whether the item is in the Cache. If it is, the UtcLastModified property is converted to a string and displayed on the page. If it is not, the item and its two dependencies are created and added to the Cache.
' When the page is loaded, use the ' AggregateCacheDependency class to make ' a cached item dependent on two files. Sub Page_Load(sender As Object, e As EventArgs) Dim Source As DataView Source = Cache("XMLDataSet") If Source Is Nothing Dim DS As New DataSet Dim FS As FileStream Dim Reader As StreamReader Dim txtDep As CacheDependency Dim xmlDep As CacheDependency Dim aggDep As AggregateCacheDependency FS = New FileStream(Server.MapPath("authors.xml"),FileMode.Open,FileAccess.Read) Reader = New StreamReader(FS) DS.ReadXml(Reader) FS.Close() Source = new DataView(ds.Tables(0)) ' Create two CacheDependency objects, one to a ' text file and the other to an XML file. ' Create a CacheDependency array with these ' two objects as items in the array. txtDep = New CacheDependency(Server.MapPath("Storage.txt")) xmlDep = New CacheDependency(Server.MapPath("authors.xml")) Dim DepArray() As CacheDependency = {txtDep, xmlDep} ' Create an AggregateCacheDependency object and ' use the Add method to add the array to it. aggDep = New AggregateCacheDependency() aggDep.Add(DepArray) ' Call the GetUniqueId method to generate ' an ID for each dependency in the array. msg1.Text = aggDep.GetUniqueId() ' Add the new data set to the cache with ' dependencies on both files in the array. Cache.Insert("XMLDataSet", Source, aggDep) If aggDep.HasChanged = True Then chngMsg.Text = "The dependency changed at: " & DateTime.Now Else chngMsg.Text = "The dependency changed last at: " & aggDep.UtcLastModified.ToString() End If cacheMsg1.Text = "Dataset created explicitly" Else cacheMsg1.Text = "Dataset retrieved from cache" End If MyLiteral.Text = Source.Table.TableName MyDataGrid.DataSource = Source MyDataGrid.DataBind() End Sub
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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