title: Find the day given date and number of days
body: <p>Am looking a function that would aid me to auto detect due date when duration period number is entered in duration textbox.Am having challenge since all the months do not end with same date number i.e. 31 as some end on 30.</p>
  
  <p>NOTE: The function should be able to automatically calculate up to next year if lets say user inputs 3 while in November 2018 its means the duration period will go up January 2019
  See the picture below
  <a href="https://i.stack.imgur.com/f3IAx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/f3IAx.png" alt="enter image description here"></a></p>
  
  <pre><code>Dim start_date As Date = dtpStart.Value
  Dim totalDays As Integer = 3 * 30
  Dim ts As TimeSpan = start_date.Add(totalDays)
  Dim end_date As Date = ts
  </code></pre>
  
  <p>I have tried the above but its giving me an error "value of type integer can not be converted to system.TimeSpan."</p>