Converting int to int64, int variable still returning negative at int.MaxValue
<p>I'm trying to display the price of an item.  The price is multiplied by the item quantity.</p>

<pre><code>int itemCost = itemPrice * itemQuanity;
</code></pre>

<p>When the quantity of the item becomes too much, the itemCost goes into negatives, meaning I need a larger int, so I changed the int to use int64.</p>

<pre><code>int64 itemCost = itemPrice * itemQuantity;
</code></pre>

<p>With this change it still outputs a negative itemCost, what am I doing wrong?</p>

<p>I tried using</p>

<pre><code>System.Convert.ToInt64(int value);
</code></pre>

<p>but that doesn't seem to work either, still getting a negative number when reaching int.MaxValue.</p>
