<p>I am looking for a Regular expression to match only if a date is in the first 28 days of the month. This is for my validator control in ASP.NET</p>

[{'answer_id': 49923, 'author': 'pilif', 'author_id': 5083, 'author_profile': 'https://Stackoverflow.com/users/5083', 'pm_score': 2, 'selected': False, 'text': "<p>I don't think this is a task very well-suited for a regexp.</p>\n\n<p>I'd try and use the library functions (DateTime.Parse for .NET) to parse the date and then check the day component of it. Everything else is duplicating half the library function anyways.</p>\n"}, {'answer_id': 49924, 'author': 'Kibbee', 'author_id': 1862, 'author_profile': 'https://Stackoverflow.com/users/1862', 'pm_score': 1, 'selected': False, 'text': '<p>Why not just covert it to a date data type and check the day?  Using a regular expression, while it could be done, just makes it overly complicated.</p>\n'}, {'answer_id': 49938, 'author': 'Simon Johnson', 'author_id': 854, 'author_profile': 'https://Stackoverflow.com/users/854', 'pm_score': 5, 'selected': True, 'text': '<p>Don\'t do this with Regex. Dates are formatted differently in different countries. Use the DateTime.TryParse routine instead:</p>\n\n<pre><code>DateTime parsedDate;\n\nif ( DateTime.TryParse( dateString, out parsedDate) &amp;&amp; parsedDate.Day &lt;= 28 )\n{\n // logic goes here.\n}\n</code></pre>\n\n<p>Regex is nearly the <a href="http://en.wikipedia.org/wiki/Golden_hammer" rel="nofollow noreferrer">golden hammer</a> of input validation, but in this instance, it\'s the wrong choice.</p>\n'}, {'answer_id': 49948, 'author': 'Sam Hasler', 'author_id': 2541, 'author_profile': 'https://Stackoverflow.com/users/2541', 'pm_score': 1, 'selected': False, 'text': '<pre><code>  ([1-9]|1\\d|2[0-8]) // matches 1 to 28 but woudn\'t allow leading zeros for single digits\n(0?[1-9]|1\\d|2[0-8]) // matches 1 to 28 and would allow 01, 02,... 09\n</code></pre>\n\n<p>(where \\d matches any digit, use [0-9] if your regex engine doesn\'t support it.)</p>\n\n<p>See also the question <a href="https://stackoverflow.com/questions/37732/what-is-the-regex-pattern-for-datetime-2008-09-01-123545">What is the regex pattern for datetime (2008-09-01 12:35:45 ) ?</a></p>\n'}, {'answer_id': 50032, 'author': 'John Sheehan', 'author_id': 1786, 'author_profile': 'https://Stackoverflow.com/users/1786', 'pm_score': 1, 'selected': False, 'text': '<p>I would use one of the DateTime.TryParse techniques in conjunction with a <a href="http://msdn.microsoft.com/en-us/library/f5db6z8k.aspx" rel="nofollow noreferrer">CustomValidator</a></p>\n'}]
['https://Stackoverflow.com/questions/49919', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/3208/']