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copied!<p><code>Convert.ToInt32</code> just returns <code>int</code>, not <code>int?</code> - so the type of the expression:</p> <pre><code>size ?? Convert.ToInt32(...) </code></pre> <p>is of type <code>int</code>. You can't use a non-nullable value type as the first operand of a null-coalescing operator expression - it can't possibly be null, so the second operand (10 in this case) could never possibly be used.</p> <p>If you're trying to <em>try</em> to use the <code>StoriesPageSize</code> cookie, but you don't know whether or not it's present, you could use:</p> <pre><code>public ActionResult Index(string keyword, int? page, int? size) { keyword = keyword ?? ""; page = page ?? 1; size = size ?? GetSizeFromCookie() ?? 10; } private int? GetSizeFromCookie() { string cookieValue = Request.Cookies.Get("StoriesPageSize").Value; if (cookieValue == null) { return null; } int size; if (int.TryParse(cookieValue, CultureInfo.InvariantCulture, out size)) { return size; } // Couldn't parse... return null; } </code></pre> <p>As mentioned in comments, you could write an extension method to make this more generally available:</p> <pre><code>public static int? GetInt32OrNull(this CookieCollection cookies, string name) { if (cookies == null) { throw ArgumentNullException("cookies"); } if (name == null) { throw ArgumentNullException("name"); } string cookieValue = cookies.Get(name).Value; if (cookieValue == null) { return null; } int size; if (int.TryParse(cookieValue, CultureInfo.InvariantCulture, out size)) { return size; } // Couldn't parse... return null; } </code></pre> <p>Note that I've changed the code to use the invariant culture - it makes sense to propagate information in cookies in the invariant culture, as it's not really meant to be user-visible or culture-sensitive. You should make sure you <em>save</em> the cookie using the invariant culture too.</p> <p>Anyway, with the extension method in place (in a static non-generic top-level class), you can use:</p> <pre><code>size = size ?? Request.Cookies.GetInt32OrNull("StoriesPageSize") ?? 10; </code></pre>

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