VirtualPathProvider.GetCacheDependency(String, IEnumerable, DateTime) Metodo
Definizione
Importante
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Crea una dipendenza della cache basata sui percorsi virtuali specificati.
public:
virtual System::Web::Caching::CacheDependency ^ GetCacheDependency(System::String ^ virtualPath, System::Collections::IEnumerable ^ virtualPathDependencies, DateTime utcStart);
public virtual System.Web.Caching.CacheDependency GetCacheDependency (string virtualPath, System.Collections.IEnumerable virtualPathDependencies, DateTime utcStart);
abstract member GetCacheDependency : string * System.Collections.IEnumerable * DateTime -> System.Web.Caching.CacheDependency
override this.GetCacheDependency : string * System.Collections.IEnumerable * DateTime -> System.Web.Caching.CacheDependency
Public Overridable Function GetCacheDependency (virtualPath As String, virtualPathDependencies As IEnumerable, utcStart As DateTime) As CacheDependency
Parametri
- virtualPath
- String
Percorso della risorsa virtuale primaria.
- virtualPathDependencies
- IEnumerable
Matrice di percorsi di altre risorse richieste dalla risorsa virtuale primaria.
- utcStart
- DateTime
Ora UTC in cui sono state lette le risorse virtuali.
Restituisce
Oggetto CacheDependency per le risorse virtuali specificate.
Esempio
Nell'esempio di codice seguente viene implementato il GetCacheDependency metodo per una classe personalizzata VirtualPathProvider . Per il codice completo necessario per eseguire l'esempio, vedere la sezione Esempio dell'argomento di panoramica della VirtualPathProvider classe.
public override CacheDependency GetCacheDependency(
string virtualPath,
System.Collections.IEnumerable virtualPathDependencies,
DateTime utcStart)
{
if (IsPathVirtual(virtualPath))
{
System.Collections.Specialized.StringCollection fullPathDependencies = null;
// Get the full path to all dependencies.
foreach (string virtualDependency in virtualPathDependencies)
{
if (fullPathDependencies == null)
fullPathDependencies = new System.Collections.Specialized.StringCollection();
fullPathDependencies.Add(virtualDependency);
}
if (fullPathDependencies == null)
return null;
// Copy the list of full-path dependencies into an array.
string[] fullPathDependenciesArray = new string[fullPathDependencies.Count];
fullPathDependencies.CopyTo(fullPathDependenciesArray, 0);
// Copy the virtual path into an array.
string[] virtualPathArray = new string[1];
virtualPathArray[0] = virtualPath;
return new CacheDependency(virtualPathArray, fullPathDependenciesArray, utcStart);
}
else
{
return Previous.GetCacheDependency(virtualPath, virtualPathDependencies, utcStart);
}
}
Public Overrides Function GetCacheDependency(ByVal virtualPath As String, ByVal virtualPathDependencies As IEnumerable, ByVal utcStart As Date) As CacheDependency
If (IsPathVirtual(virtualPath)) Then
Dim fullPathDependencies As System.Collections.Specialized.StringCollection
fullPathDependencies = Nothing
' Get the full path to all dependencies.
For Each virtualDependency As String In virtualPathDependencies
If fullPathDependencies Is Nothing Then
fullPathDependencies = New System.Collections.Specialized.StringCollection
End If
fullPathDependencies.Add(virtualDependency)
Next
If fullPathDependencies Is Nothing Then
Return Nothing
End If
Dim fullPathDependenciesArray As String()
fullPathDependencies.CopyTo(fullPathDependenciesArray, 0)
Return New CacheDependency(fullPathDependenciesArray, utcStart)
Else
Return Previous.GetCacheDependency(virtualPath, virtualPathDependencies, utcStart)
End If
End Function
Commenti
L'implementazione predefinita del GetCacheDependency metodo restituisce null
. Per memorizzare nella cache le risorse virtuali per un uso successivo, è necessario eseguire l'override del GetCacheDependency metodo o del GetFileHash metodo .