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GacMembershipCondition Class

Determines whether an assembly belongs to a code group by testing its global assembly cache membership. This class cannot be inherited.

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

'Declaration

<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public NotInheritable Class GacMembershipCondition _
	Implements IMembershipCondition, ISecurityEncodable, ISecurityPolicyEncodable
Remarks

All assemblies installed in the global assembly cache are granted the FullTrust permission set.

Examples

The following example demonstrates the use of the GacMembershipCondition class.


Imports System
Imports System.Security
Imports System.Security.Policy
Imports System.Collections

Public Class GacMembershipConditionDemo

    ' Demonstrate the Copy method, which creates an identical 
    ' copy of the current permission.
    Private Function CopyDemo() As Boolean
        Console.WriteLine( _
            "*************************************************************")
        Dim Gac1 As New GacMembershipCondition
        Console.WriteLine("Original membership condition = ")
        Console.WriteLine(Gac1.ToXml().ToString())
        Try
            Dim membershipCondition As IMembershipCondition = Gac1.Copy()
            Console.WriteLine("Result of Copy = ")
            Console.WriteLine(CType(membershipCondition, _
                GacMembershipCondition).ToXml().ToString())
        Catch e As Exception
            Console.WriteLine(("Copy failed : " & Gac1.ToString() & _
                e.ToString()))
            Return False
        End Try

        Return True
    End Function 'CopyDemo

    ' Demonstrate the Check method, which determines whether the specified 
    ' evidence satisfies the membership condition.
    Private Function CheckDemo() As Boolean
        Console.WriteLine( _
            "*************************************************************")
        Dim Gac1 As New GacMembershipCondition
        Dim myGac As New GacInstalled
        Try
            Dim hostEvidence() As Object = {myGac}
            Dim assemblyEvidence() As Object

            Dim myEvidence As New Evidence(hostEvidence, assemblyEvidence)
            Dim retCode As Boolean = Gac1.Check(myEvidence)
            Console.WriteLine(("Result of Check = " & retCode.ToString() _
                & ControlChars.Lf))
        Catch e As Exception
            Console.WriteLine(("Check failed : " & Gac1.ToString() & _ 
                e.ToString()))
            Return False
        End Try
        Return True
    End Function 'CheckDemo

    ' Demonstrate the GetHashCode method, which returns a hash code
    ' for the specified membership condition.
    Private Function GetHashCodeDemo() As Boolean
        Console.WriteLine( _
            "*************************************************************")
        Dim Gac1 As New GacMembershipCondition
        Try
            Console.WriteLine( _
                ("Result of GetHashCode for a GacMembershipCondition = " _
                & Gac1.GetHashCode().ToString() & ControlChars.Lf))
        Catch e As Exception
            Console.WriteLine(("GetHashCode failed : " & _
                Gac1.ToString() & e.ToString()))
            Return False
        End Try

        Return True
    End Function 'GetHashCodeDemo

    'Demonstrate the ToXml and FromXml methods, including the overloads. 
    ' ToXml creates an XML encoding of the membership condition and its 
    ' current state; FromXml reconstructs a membership condition with the 
    ' specified state from the XML encoding.
    Private Function ToFromXmlDemo() As Boolean
        Console.WriteLine( _
            "*************************************************************")
        Try
            Dim Gac1 As New GacMembershipCondition
            Dim Gac2 As New GacMembershipCondition

            ' Roundtrip a GacMembershipCondition to and from an XML encoding.
            Gac2.FromXml(Gac1.ToXml())
            Dim result As Boolean = Gac2.Equals(Gac1)
            If result Then
                Console.WriteLine(("Result of ToXml() = " & _ 
                    Gac2.ToXml().ToString()))
                Console.WriteLine(("Result of ToFromXml roundtrip = " & _ 
                    Gac2.ToString()))
            Else
                Console.WriteLine(Gac2.ToString())
                Console.WriteLine(Gac1.ToString())
                Return False
            End If

            Dim Gac3 As New GacMembershipCondition
            Dim Gac4 As New GacMembershipCondition
            Dim policyEnumerator As IEnumerator = _
                SecurityManager.PolicyHierarchy()
            While policyEnumerator.MoveNext()
                Dim currentLevel As PolicyLevel = _
                    CType(policyEnumerator.Current, PolicyLevel)
                If currentLevel.Label = "Machine" Then
                    Console.WriteLine(("Result of ToXml(level) = " & _
                        Gac3.ToXml(currentLevel).ToString()))
                    Gac4.FromXml(Gac3.ToXml(), currentLevel)
                    Console.WriteLine(("Result of FromXml(element, level) = " _
                        & Gac4.ToString()))
                End If
            End While
        Catch e As Exception
            Console.WriteLine(("ToFromXml failed. " & e.ToString()))
            Return False
        End Try

        Return True
    End Function 'ToFromXmlDemo

    ' Invoke all demos.
    Public Function RunDemo() As Boolean

        Dim returnCode As Boolean = True
        Dim tempReturnCode As Boolean

        ' Call the Copy demo.
        tempReturnCode = CopyDemo()
        If tempReturnCode = True Then
            Console.Out.WriteLine("Copy demo completed successfully.")
        Else
            Console.Out.WriteLine("Copy demo failed.")
        End If

        returnCode = tempReturnCode AndAlso returnCode

        ' Call the Check demo.
        tempReturnCode = CheckDemo()
        If tempReturnCode = True Then
            Console.Out.WriteLine("Check demo completed successfully.")
        Else
            Console.Out.WriteLine("Check demo failed.")
        End If

        returnCode = tempReturnCode AndAlso returnCode

        ' Call the GetHashCode demo.
        tempReturnCode = GetHashCodeDemo()
        If tempReturnCode = True Then
            Console.Out.WriteLine("GetHashCode demo completed successfully.")
        Else
            Console.Out.WriteLine("GetHashCode demo failed.")
        End If

        returnCode = tempReturnCode AndAlso returnCode

        ' Call the ToFromXml demo.
        tempReturnCode = ToFromXmlDemo()
        If tempReturnCode = True Then
            Console.Out.WriteLine("ToFromXml demo completed successfully.")
        Else
            Console.Out.WriteLine("ToFromXml demo failed.")
        End If

        returnCode = tempReturnCode AndAlso returnCode
        Return returnCode
    End Function 'RunDemo

    ' Test harness.
    Public Overloads Shared Sub Main(ByVal args() As [String])
        Try
            Dim testcase As New GacMembershipConditionDemo
            Dim returnCode As Boolean = testcase.RunDemo()
            If returnCode Then
                Console.Out.WriteLine( _
                    "The GacMembershipCondition demo completed successfully.")
                Console.Out.WriteLine("Press the Enter key to exit.")
                Dim consoleInput As String = Console.ReadLine()
                System.Environment.ExitCode = 100
            Else
                Console.Out.WriteLine("The GacMembershipCondition demo failed.")
                Console.Out.WriteLine("Press the ENTER key to exit.")
                Dim consoleInput As String = Console.ReadLine()
                System.Environment.ExitCode = 101
            End If
        Catch e As Exception
            Console.Out.WriteLine("The GacIdentityPermission demo failed.")
            Console.WriteLine(e.ToString())
            Console.Out.WriteLine("Press the Enter key to exit.")
            Dim consoleInput As String = Console.ReadLine()
            System.Environment.ExitCode = 101
        End Try
    End Sub 'Main
End Class 'GacMembershipConditionDemo



Inheritance Hierarchy

System.Object
  System.Security.Policy.GacMembershipCondition
Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role not supported), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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