Question

根据日期时间值，我将值插入缓存中：

Dim Value1 As String = "value1"
Dim Value2 As String = "value2"
Dim Key1 As String = "Key" & New Date(2014, 1, 1, 1, 1, 0).ToString
Dim Key2 As String = "Key" & New Date(2014, 1, 1, 1, 2, 0).ToString
HttpContext.Current.Cache.Insert(Key1, Value1)
HttpContext.Current.Cache.Insert(Key2, Value2)

是否可以使用另一个缓存项作为CacheDependency使这些缓存项无效？

我尝试了以下内容，但这不起作用：

Dim Keys As String() = New String(0) {}
Keys(0) = "OtherKey"
Dim MyDependency As New System.Web.Caching.CacheDependency(Nothing, Keys)
HttpContext.Current.Cache.Insert(Key1, Value1, MyDependency)
HttpContext.Current.Cache.Insert(Key2, Value2, MyDependency)

'To clear all cache items:
HttpContext.Current.Cache.Remove("OtherKey")

当我使用它时（没有remove语句），永远不能在缓存中找到这些项。我在这里做错了什么？

Answer 1

如果要将CacheDependency用于另一个缓存键：

您必须在缓存中找到您所依赖的密钥（即 OtherKey ）（请参阅this article）。否则，您的商品将无法在缓存中找到。
您需要为每个项目创建不同的CacheDependency实例。否则，您将收到错误An attempt was made to reference a CacheDependency object from more than one Cache entry（请参阅this question的答案）

因此，插入项目的代码将是这样的：

' Make sure OtherKey is found in the cache
HttpContext.Current.Cache.Insert("OtherKey", "SomeValue")

' Add the items with a different CacheDependency instance per item
Dim Keys As String() = New String(0) {}
Keys(0) = "OtherKey"
HttpContext.Current.Cache.Insert(Key1, Value1, New System.Web.Caching.CacheDependency(Nothing, Keys))
HttpContext.Current.Cache.Insert(Key2, Value2, New System.Web.Caching.CacheDependency(Nothing, Keys))

请注意，如果您未使用密钥 OtherKey 添加缓存项目，则永远不会找到相关项目。

然后，当您从缓存中删除OtherKey时，将自动删除相关项。因此，此行会自动从缓存中删除 Key1 和 Key2 ：

HttpContext.Current.Cache.Remove("OtherKey")

希望它有所帮助！

基于依赖关键字清除缓存

1 个答案: