public class EventHandlers
{

    public EventHandlers( Permissions per)
    {
        per.Data = "safafs"; //Первый случай
    }

    public void safd()
    {
       per.Data = "safafs"; //Второй случай
    }

}

public class EventHandlers
{
    Permissions Permissions;
    public EventHandlers( Permissions per)
    {
        Permissions = per;
        //...
    }

    public void safd()
    {
       Permissions.Data = "safafs";
    }
}