Which of the following code blocks are more logical?
<p>Imagine a condintion should be true for a method to do its stuff. Which block represents the best approach (performance related and readability), or if not what is your suggestion?!</p>

<pre><code>private void method()
{
    if(!condition)
    {
     MessageBox.Show("ERROR!");
     return;
    }     
    else
    {
        //DO STUFF
    }
}
</code></pre>

<p>OR</p>

<pre><code>private void method()
{
    if(condition)
    {
         //DO STUFF
    }     
    else
    {
         MessageBox.Show("ERROR!");
         return;
    }
}
</code></pre>
