Why I am getting null exception when using an Interface : <pre><code>public class Blah
{
    public bool Whatever { get; set; }
    public string WhatYouJustSaid { get; set; }
}

public interface IBlah
{
    Blah BlahValues { get; set; }
}

class Class1:IBlah
{
    public Blah BlahValues { get; set; }
}
</code></pre>

<p>And then for example:</p>

<pre><code>   Class1 c1 = new Class1();
   c1.BlahValues.WhatYouJustSaid = "nothing";
    c1.BlahValues.Whatever = false;
</code></pre>

<p>So how should I change my code that <code>BlahValues</code> doesn't get null? </p>
