如何拒绝与CAS断言？(How to deny Assert with CAS?)

 在这段代码中，我希望禁止ReadFileSystem方法断言文件系统的权限。 
 
 我预计这会抛出fileIo.Assert（），但它不会。 为什么？ 
 
using System.Security.Permissions;
static void Main(string[] args)
{
    var fileIo = new FileIOPermission(PermissionState.Unrestricted);
    var secuPerm = new SecurityPermission(SecurityPermissionFlag.Assertion);
    PermissionSet set = new PermissionSet(PermissionState.Unrestricted);
    set.AddPermission(fileIo);
    set.AddPermission(secuPerm);
    set.Deny();
    ReadFileSystem();
    Console.Read();
}

private static void ReadFileSystem()
{
    var fileIo = newFileIOPermission(PermissionState.Unrestricted);
    fileIo.Assert();

    DirectoryInfo dir = new DirectoryInfo("C:/");
    dir.GetDirectories();
}
 
 更新 
 
 这里有很好的CAS链接： http ： //blogs.msdn.com/shawnfa/archive/2004/08/25/220458.aspx 

In this code, I'd like the ReadFileSystem method to be forbidden to Assert a permission on the filesystem.
 
I expected this will throw at fileIo.Assert(), but it doesn't. Why?
 
using System.Security.Permissions;
static void Main(string[] args)
{
    var fileIo = new FileIOPermission(PermissionState.Unrestricted);
    var secuPerm = new SecurityPermission(SecurityPermissionFlag.Assertion);
    PermissionSet set = new PermissionSet(PermissionState.Unrestricted);
    set.AddPermission(fileIo);
    set.AddPermission(secuPerm);
    set.Deny();
    ReadFileSystem();
    Console.Read();
}

private static void ReadFileSystem()
{
    var fileIo = newFileIOPermission(PermissionState.Unrestricted);
    fileIo.Assert();

    DirectoryInfo dir = new DirectoryInfo("C:/");
    dir.GetDirectories();
}
 
Update
 
Great link here on CAS : http://blogs.msdn.com/shawnfa/archive/2004/08/25/220458.aspx

原文：https://stackoverflow.com/questions/604450