将 System.Type 类保存到变量并使用变量引用(而不是实例化)类型

我了解如何将类型类分配给变量：

Type type = ("System.Security.AccessControl.FileSecurity").GetType();

那么，如何将此变量用作已实例化的对象的引用？

如果我尝试以下操作：

type instance = new SomeOtherType();

我收到以下错误代码：

找不到类型或命名空间名称"type"（是否缺少 using 指令或程序集引用？

例：

FileSecurity fSecurity = fInfo.GetAccessControl();

我希望能够做到：

Type sometype = ("System.Security.AccessControl.FileSecurity").GetType();
sometype mynewtype = fInfo.GetAccessControl(); 

编辑：为了更好地解释为什么我首先尝试这样做，请查看以下代码：

public static class FileFolderPermissions
{
    public static void SetFileFolderPermissions()
    {
        try
        {
            DirectoryInfo dInfo = new DirectoryInfo(@"D:'SomeFolder");
            DirectorySecurity dSecurity = dInfo.GetAccessControl();
            FileInfo fInfo = new FileInfo(@"D:'Test.txt");
            FileSecurity fSecurity = fInfo.GetAccessControl();
            dSecurity.AddAccessRule(new FileSystemAccessRule("TestAccount",
                    FileSystemRights.FullControl, InheritanceFlags.ObjectInherit | InheritanceFlags.ContainerInherit,
                    PropagationFlags.NoPropagateInherit, AccessControlType.Allow));
            dInfo.SetAccessControl(dSecurity);
            fSecurity.AddAccessRule(new FileSystemAccessRule("TestAccount",
                    FileSystemRights.FullControl, AccessControlType.Allow));
            fInfo.SetAccessControl(fSecurity);
        }
        catch
        {
            Console.WriteLine("Error.");
        }
    }
}

我正在尝试做的是创建一种通用方法来设置对象是文件还是目录的ACL。 如您所见，上面的代码中有很多代码重复。 所以我一直在试图弄清楚如何通常将"DirectoryInfo"或"FileInfo"传递给上面的代码，这样我就不会有所有的重复。

我遇到过能够将类型保存到变量中的情况。 但是我看到的大多数处理 Activator 的示例都涉及创建对象的实例。

如您所见，这不是创建实例。 所以这就是为什么我想知道，"如何概括FileSecurity/DirectorySecurity fSecurity/dSecurity部分"？

感谢您的帮助。

解决方案：基于 nawfal 提供的答案，这里是更新的类，它现在适用于 FileInfo 和 DirectoryInfo 以及 Main 方法中的代码。 注意：我注释掉了处理抛出异常的部分，因为我还没有实现异常。

public static class DynFileFolderPermissions
{
    public static void SetFileFolderPermissions(dynamic info, FileSystemAccessRule FileAccessRule)
    {
        // if (!(info is System.IO.FileInfo) || !(info is System.IO.DirectoryInfo))
        //    throw new System.InvalidOperationException("Incorrect Type.");
        try
        {
            var security = info.GetAccessControl();
            security.AddAccessRule(FileAccessRule);
            info.SetAccessControl(security);
        }
        catch
        {
            Console.WriteLine("Error.");
        }
    }
}
// Main
class Program
{
    static void Main(string[] args)
    {
        // Grants FullControl to user "TestUser" on file D:'Test.txt
        var fileInfo = new FileInfo(@"D:'Test.txt");
        var FileAccessRule = new FileSystemAccessRule("TestUser", FileSystemRights.FullControl, AccessControlType.Allow);
        DynFileFolderPermissions.SetFileFolderPermissions(fileInfo, FileAccessRule);
        // Grants FullControl to user "TestUser" on directory D:'Test
        var directoryInfo = new DirectoryInfo(@"D:'Test");
        var DirectoryAccessRule = new FileSystemAccessRule("TestUser", FileSystemRights.FullControl,
                    InheritanceFlags.ObjectInherit | InheritanceFlags.ContainerInherit,
                    PropagationFlags.None, AccessControlType.Allow);
        DynFileFolderPermissions.SetFileFolderPermissions(directoryInfo, DirectoryAccessRule);
    }
}

public static void SetFileFolderPermissions(dynamic info)
{
    if (!(info is FileInfo) || !(info is DirectoryInfo))
        throw new explosion;
    try
    {
        var security = info.GetAccessControl();
        security.AddAccessRule(new FileSystemAccessRule(...));
        info.SetAccessControl(security);
    }
    catch
    {
        Console.WriteLine("Error.");
    }
}

public static void SetFilePermissions(string path)
{
    SetFileFolderPermissions
    (
        new FileInfo(path), 
        new FileSystemAccessRule
        (
            "TestAccount", 
            FileSystemRights.FullControl, 
            AccessControlType.Allow
        )
    );
}
//so that now nobody from outside can pass any dumb object to it
static void SetFileFolderPermissions(dynamic info, FileSystemAccessRule rule)
{
    try
    {
        var security = info.GetAccessControl();
        security.AddAccessRule(rule);
        info.SetAccessControl(security);
    }
    catch
    {
        Console.WriteLine("Error.");
    }
}
public static void SetFolderPermissions(string path)
{
    SetFileFolderPermissions
    (
        new DirectoryInfo(path), 
        new FileSystemAccessRule
        (
            "TestAccount",
             FileSystemRights.FullControl,
             InheritanceFlags.ObjectInherit | InheritanceFlags.ContainerInherit,
             PropagationFlags.NoPropagateInherit,
             AccessControlType.Allow
        )
    );
}