' To use the custom trust manager MyTrustManager, compile it into CustomTrustManager.dll, 
' place that assembly in the GAC, and  put the following elements in
' an ApplicationTrust.config file in the config folder in the Microsoft .NET framework
' installation folder.
'<?xml version="1.0" encoding="utf-8" ?>
'<configuration>
'    <mscorlib>
'        <security>
'            <policy>
'                <ApplicationSecurityManager>
'                    <ApplicationEntries />
'                    <IApplicationTrustManager class="MyNamespace.MyTrustManager, CustomTrustManager, Version=1.0.0.3, Culture=neutral, PublicKeyToken=5659fc598c2a503e"/>
'                </ApplicationSecurityManager>
'            </policy>
'        </security>
'    </mscorlib>
'</configuration>
Imports System
Imports System.Security
Imports System.Security.Policy
Imports System.Windows.Forms


Public Class MyTrustManager
    Implements IApplicationTrustManager

    Public Function DetermineApplicationTrust(ByVal appContext As ActivationContext, ByVal context As TrustManagerContext) As ApplicationTrust Implements IApplicationTrustManager.DetermineApplicationTrust
        Dim trust As New ApplicationTrust(appContext.Identity)
        trust.IsApplicationTrustedToRun = False

        Dim asi As New ApplicationSecurityInfo(appContext)
        trust.DefaultGrantSet = New PolicyStatement(asi.DefaultRequestSet, _
        PolicyStatementAttribute.Nothing)
        If context.UIContext = TrustManagerUIContext.Run Then
            Dim message As String = "Do you want to run " + asi.ApplicationId.Name + " ?"
            Dim caption As String = "MyTrustManager"
            Dim buttons As MessageBoxButtons = MessageBoxButtons.YesNo
            Dim result As DialogResult

            ' Displays the MessageBox.
            result = MessageBox.Show(message, caption, buttons)

            If result = DialogResult.Yes Then
                trust.IsApplicationTrustedToRun = True
                If Not (context Is Nothing) Then
                    trust.Persist = context.Persist
                Else
                    trust.Persist = False
                End If
            End If
        End If
        Return trust

    End Function 'DetermineApplicationTrust

    Public Function ToXml() As SecurityElement Implements IApplicationTrustManager.ToXml
        Dim se As New SecurityElement("IApplicationTrustManager")
        se.AddAttribute("class", GetType(MyTrustManager).AssemblyQualifiedName)
        Return se

    End Function 'ToXml

    Public Sub FromXml(ByVal se As SecurityElement) Implements IApplicationTrustManager.FromXml
        If se.Tag <> "IApplicationTrustManager" OrElse _
        CStr(se.Attributes("class")) <> GetType(MyTrustManager).AssemblyQualifiedName Then
            Throw New ArgumentException("Invalid tag")
        End If

    End Sub 'FromXml 
End Class 'MyTrustManager