NulltoString eq in C#
<p>I have this method to validate email addresses:</p>

<pre><code>public static bool isEmail(string inputEmail)
{
    inputEmail = NulltoString(inputEmail);
    string strRegex = @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
                      @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
                      @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
    Regex re = new Regex(strRegex);
    if (re.IsMatch(inputEmail))
        return (true);
    else
        return (false);
}
</code></pre>

<p>But I get the error: <code>The name 'NulltoString' does not exist in the current context</code>.</p>

<p>Is there a <code>string</code> method that is equivalent to <code>NulltoString()</code>?</p>
