C# VS2010 - Why am I getting the message "An object reference is required for the non-static field"?
<p>I've boiled this problem down to a very simple program:</p>

<pre><code>public Form1()
{
    InitializeComponent();

    TextBox tb1;

    tb1 = textBox1;             // this line is OK
    tb1 = this.textBox1;        // this line is OK
    tb1 = Form1.textBox1;       // this line generates error message    

    }
</code></pre>

<p>If you mouse over 'textBox1', 'this.textBox1', and 'Form1.textBox1', the tool tip says "TextBox Form1.textBox1" in all cases.</p>

<p>(see www.firish.com/tb1.jpg and www.firish.com/tb2.jpg for screen dumps showing tool tips)</p>

<p>I passed this around the office a bit but no one here could really explain why the 3rd example doesn't compile but didn't get much other than 'uh-huh', 'hmm...' and a couple of shrugs.</p>
