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CacheDependency.HasChanged Property

Gets a value indicating whether the CacheDependency object has changed.

[Visual Basic]
Public ReadOnly Property HasChanged As Boolean
[C#]
public bool HasChanged {get;}
[C++]
public: __property bool get_HasChanged();
[JScript]
public function get HasChanged() : Boolean;

Property Value

true if the CacheDependency object has changed; otherwise, false. The default is false.

Remarks

You can add an item to an ASP.NET application's Cache with a CacheDependency. When the CacheDependency changes, the item added to the Cache is invalidated. You can use this property to determine if a CacheDependency has changed, and recreate an item in the Cache if that has occurred.

Example

[Visual Basic, C#] The following example demonstrates using the HasChanged property to determine if a CacheDependency changed since the previous request for an item in the Cache. The dt value passed in the start parameter is set to DateTime.Now.

[Visual Basic] 
' Insert the cache item.
Dim dep As New CacheDependency(fileName, dt)
myCache.Insert("key", "value", dep)

' Check whether CacheDependency.HasChanged is true.
If dep.HasChanged Then
   Response.Write("<p>The dependency has changed.")
Else
   Response.Write("<p>The dependency has not changed.")
End If 

[C#] 
// Insert the cache item.
CacheDependency dep = new CacheDependency(fileName, dt);
cache.Insert("key", "value", dep);

// Check whether CacheDependency.HasChanged is true.
if (dep.HasChanged)
  Response.Write("<p>The dependency has changed.");  
else Response.Write("<p>The dependency has not changed.");

[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 2000, Windows XP Professional, Windows Server 2003 family

See Also

CacheDependency Class | CacheDependency Members | System.Web.Caching Namespace

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