CacheDependency Constructor (String)


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Initializes a new instance of the CacheDependency class that monitors a file or directory for changes.

Namespace:   System.Web.Caching
Assembly:  System.Web (in System.Web.dll)

public CacheDependency(
	string filename


Type: System.String

The path to a file or directory that the cached object is dependent upon. When this resource changes, the cached object becomes obsolete and is removed from the cache.

If the directory or file specified in the filename parameter is not found in the file system, it will be treated as missing. If the directory or file is missing when the object with the dependency is added to the Cache, the cached object will be removed from the Cache when the directory or file is created.

For example, assume that you add an object to the Cache with a dependency on the following file path: c:\stocks\xyz.dat. If that file is not found when the CacheDependency object is created, but is created later, the cached object is removed upon the creation of the xyz.dat file.

The following code example creates an instance of the CacheDependency class with a dependency on an XML file. The Cache.Insert method then adds an item to the Cache that is dependent upon that file.

CacheDependency dep = new CacheDependency(Server.MapPath("isbn.xml"));
Cache.Insert("ISBNData", Source, dep);

You can also use the following technique to add an item to the Cache with a dependency on a file.

// Make key1 dependent on a file.
CacheDependency dependency = new CacheDependency(Server.MapPath("isbn.xml"));

Cache.Insert("key1", "Value 1", dependency);

.NET Framework
Available since 1.1
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