Relay/ICommand vs DelegateCommand -- Differences

据我所知，下面的代码可以从Relay/ICommand命令更改为Delegate命令，并且仍然以相同的方式绑定命令!如果我错了，它们的区别和用途是什么?

private DelegateCommand something;
public DelegateCommand Something

下面是完整的实现

private RelayCommand something;
public ICommand Something
{
    get
    {
        if (something == null)
            something = new RelayCommand(SomethingMethod, CanSomething);
        return something;
    }
}
private bool CanSomething(object parameter)
{
    //just for readability return true
    return true;
}
private void SomethingMethod(object parameter)
{
    using (DatabaseContext context = new DatabaseContext())      
    {
        try { }
        catch(Exception ex)
        {
            throw new ApplicationException(string.Format("Something {0} to {1}", file, directory), ex);
        }
    }
}