title: Wait till string is not null, then proceed with the code
body: <p>I have a <code>public string</code> called simply <code>m</code>. The code shall only proceed when <code>m</code> is not <code>null</code> anymore. As long as <code>m</code> is <code>null</code> it should just wait. Any suggestions on how to do that? ( Without pausing the entire program, otherwise <code>m</code> would never change)</p>