Modifying Directory Access Rules

Here is the routine to do the work:

 
// Adds an ACL entry on the specified directory for the specified account.
public static void AddDirectorySecurity(
    string folderName, 
 string account, 
 FileSystemRights rights, 
 AccessControlType controlType)
{
    // Create a new DirectoryInfo object.
    DirectoryInfo dirInfo = new DirectoryInfo(folderName);

    // Get a DirectorySecurity object that represents the 
    // current security settings.
    DirectorySecurity dSecurity = dirInfo.GetAccessControl();

    // Add the FileSystemAccessRule to the security settings. 
    dSecurity.AddAccessRule(new FileSystemAccessRule(account,
                                                    rights,
                                                    controlType));

    // Set the new access settings.
    dirInfo.SetAccessControl(dSecurity);
}

Sample usage of the routine:

DirectoryInfo targetDir = GetDirectoryInfo();    
// eg Deny the current user write permission on a given directory       
AddDirectorySecurity(targetDir.FullName, Environment.UserName, 
    FileSystemRights.Write, AccessControlType.Deny);

There is a remove as well:

// Removes an ACL entry on the specified directory for the specified account.
public static void RemoveDirectorySecurity(string folderName, string account, FileSystemRights rights, AccessControlType controlType)
{
    // Create a new DirectoryInfo object.
    DirectoryInfo dInfo = new DirectoryInfo(folderName);

    // Get a DirectorySecurity object that represents the 
    // current security settings.
    DirectorySecurity dSecurity = dInfo.GetAccessControl();

    // Add the FileSystemAccessRule to the security settings. 
    dSecurity.RemoveAccessRule(new FileSystemAccessRule(account,
                                                    rights,
                                                    controlType));

    // Set the new access settings.
    dInfo.SetAccessControl(dSecurity);

}

These methods are useful when unit testing writing to a directory without the appropriate permission.

Generic Event Firer

Here is the common .NET pattern for firing some event

// Here is the event
public event EventHandler<ReminderEventArgs> ReminderOccured;
...
// And to fire it
EventHandler<ReminderEventArgs> reminderOccured = this.ReminderOccured;
if (reminderOccured != null)
{
    reminderOccured(this, new ReminderEventArgs { Reminder = reminder });
}

This is a common pattern so a helper class to tidy this up might be of some use:

public static class EventFirer
{
    public static void FireEvent<TEventArgs>(object firer, 
        EventHandler<TEventArgs> eventToFire, TEventArgs eventargs)
        where TEventArgs : EventArgs
    {
        EventHandler<TEventArgs> eventToFireReference = eventToFire;
        if (eventToFireReference != null)
        {
            eventToFireReference(firer, eventargs);
        }
    }

    public static void FireEvent(object firer, EventHandler eventToFire, 
        EventArgs eventargs)
    {
        EventHandler eventToFireReference = eventToFire;
        if (eventToFireReference != null)
        {
            eventToFireReference(firer, eventargs);
        }
    }
}

With this class firing the event becomes:

EventFirer.FireEvent<ReminderEventArgs>(this, 
    this.ReminderOccured, 
    new ReminderEventArgs { Reminder = reminder });