CacheDependency.UtcLastModified 属性
定义
获取依赖项的上次更改时间。Gets the time when the dependency was last changed.
public:
property DateTime UtcLastModified { DateTime get(); };
public DateTime UtcLastModified { get; }
member this.UtcLastModified : DateTime
Public ReadOnly Property UtcLastModified As DateTime
属性值
依赖项的上次更改时间。The time when the dependency was last changed.
示例
下面的代码示例使用 AggregateCacheDependency 类将具有两个对象依赖项的项添加 CacheDependency 到中 Cache 。The following code example uses the AggregateCacheDependency class to add an item, with two CacheDependency object dependencies, to the Cache. 发出对该项的请求时 Cache ,该代码将检查该项是否在中 Cache 。When a request for the Cache item is made, the code checks whether the item is in the Cache. 如果为,则将该 UtcLastModified 属性转换为字符串,并将其显示在该页上。If it is, the UtcLastModified property is converted to a string and displayed on the page. 如果不是,则创建项及其两个依赖项并将其添加到中 Cache 。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
注解
此属性以协调世界时 (UTC) (也称为格林尼治标准时间) 来度量。This property is measured in Coordinated Universal Time (UTC) (also known as Greenwich Mean Time).