title: Regex to Allow 1st letter of a string only Alphabet in C#
body: <p>I have a case where i need to allow Alphanumeric but 1st letter of the string should always be Alphabet only</p>
  <p>Below is sample case</p>
  <pre><code>string text1 = &quot;A1222&quot;; Valid
  string text2 = &quot;1A22&quot;; // Invalid
  </code></pre>