Question

Is there a faster way then to simply catch an exception like below?

try
{
    date = new DateTime(model_.Date.Year, model_.Date.Month, (7 * multiplier) + (7 - dow) + 2);
}
catch (Exception)
{
    // This is an invalid date
}

Answer 1

String DateString = String.Format("{0}/{1}/{2}", model_.Date.Month, (7 * multiplier) + (7 - dow) + 2),model_.Date.Year);

DateTime dateTime;
if(DateTime.TryParse(DateString, out dateTime))
{
    // valid
}

As the comment pointed out by GenericTypeTea, this code will not run any faster than what you have now. However, I believe you gain in readability.