HostSecurityManager.DetermineApplicationTrust Method (Evidence, Evidence, TrustManagerContext)

 

Determines whether an application should be executed.

Namespace:   System.Security
Assembly:  mscorlib (in mscorlib.dll)

<SecurityCriticalAttribute>
<SecurityPermissionAttribute(SecurityAction.Assert, Unrestricted := True)>
Public Overridable Function DetermineApplicationTrust (
	applicationEvidence As Evidence,
	activatorEvidence As Evidence,
	context As TrustManagerContext
) As ApplicationTrust

Parameters

applicationEvidence
Type: System.Security.Policy.Evidence

The evidence for the application to be activated.

activatorEvidence
Type: System.Security.Policy.Evidence

Optionally, the evidence for the activating application domain.

context
Type: System.Security.Policy.TrustManagerContext

The trust context.

Return Value

Type: System.Security.Policy.ApplicationTrust

An object that contains trust information about the application.

Exception Condition
ArgumentNullException

applicationEvidence is null.

ArgumentException

An ActivationArguments object could not be found in the application evidence.

-or-

The ActivationContext property in the activation arguments is null.

InvalidOperationException

The ApplicationTrust grant set does not contain the minimum request set specified by the ActivationContext.

This method can be overridden by a derived class. The base implementation calls the application security manager to determine if the application should be executed.

The base implementation does not use the activator evidence. However, an overridden implementation could use the activator evidence to determine the security evidence for the application domain attempting to activate the application.

The following example shows how to override the DetermineApplicationTrust method for a custom host security manager. This example is part of a larger example provided for the HostSecurityManager class.

    <SecurityPermissionAttribute(SecurityAction.Demand, Execution:=True), SecurityPermissionAttribute(SecurityAction.Assert, Unrestricted:=True)> _
    Public Overrides Function DetermineApplicationTrust(ByVal applicationEvidence As Evidence, ByVal activatorEvidence As Evidence, ByVal context As TrustManagerContext) As ApplicationTrust
        If applicationEvidence Is Nothing Then
            Throw New ArgumentNullException("applicationEvidence")
        End If
        ' Get the activation context from the application evidence.
        ' This HostSecurityManager does not examine the activator evidence
        ' nor is it concerned with the TrustManagerContext;
        ' it simply grants the requested grant in the application manifest.
        Dim enumerator As IEnumerator = applicationEvidence.GetHostEnumerator()
        Dim activationArgs As ActivationArguments = Nothing
        While enumerator.MoveNext()
            activationArgs = enumerator.Current '
            If Not (activationArgs Is Nothing) Then
                Exit While
            End If
        End While
        If activationArgs Is Nothing Then
            Return Nothing
        End If
        Dim activationContext As ActivationContext = activationArgs.ActivationContext
        If activationContext Is Nothing Then
            Return Nothing
        End If
        Dim trust As New ApplicationTrust(activationContext.Identity)
        Dim asi As New ApplicationSecurityInfo(activationContext)
        trust.DefaultGrantSet = New PolicyStatement(asi.DefaultRequestSet, PolicyStatementAttribute.Nothing)
        trust.IsApplicationTrustedToRun = True
        Return trust

    End Function 'DetermineApplicationTrust
End Class

.NET Framework
Available since 2.0
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