Determining whether the new date is the default new DateTime() or not
<p>Here is my question:</p>

<pre><code>DateTime previousDate = new DateTime();
DateTime currentDate = new DateTime();
foreach (ApproverVo approver in approvers)
{
    if (previousDate != null)
    {
        currentDate = (DateTime)approver.ApprovalDate;
        totalTimeSpan += (currentDate - previousDate).TotalDays;
        previousDate = currentDate;
    } else
        previousDate = (DateTime)approver.ApprovalDate;
}
</code></pre>

<p>When the previous date is declared in the beginning, it contains the default value of DateTime(). What I want to do is to find out whether the previousDate has been assigned with proper date or not.</p>

<p>Advice please, thanks</p>
