VirtualPathProvider.GetCacheDependency(String, IEnumerable, DateTime) Metodo

Definizione

Spazio dei nomi:

System.Web.Hosting

Assembly:

System.Web.dll

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

CacheDependency

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 .