title: how to use extension methods across many projects .
body: <p>i am learning extension method, a very handy feature, which can save number of hours of coding, provides reusability. what i'm doing now a days, daily i'm creating 10 extension methods which useful in day to day scenario. but i'm not getting how to use these extension methods, everytime we need to add dll and reference it. or is there  any smart way where we can use . </p>
  
  <p>suppose </p>
  
  <pre><code> public static bool isValidMail(this string str)
          {
              Regex reg = new Regex(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$");
              return reg.IsMatch(str);
          }
  </code></pre>
  
  <p>if i created 100 extension methods like this , then for every project should i need to reference this static class dll. as i work with multplie projects. is there any way that we can put these extension methods in centralized location or some assembly cache, where we can easily add using statement and get access to all static methods. </p>
  
  <p>can we do like this ? </p>
  
  <ol>
  <li><p>whenever we do create new project, can VS automatically add the extensionmethods which we created, so that in evey project we can access it. rather than adding dll everytime </p></li>
  <li><p>i want to know how you people do. 
  i hope no one down votes it, just curious abt implementation of extension methods </p></li>
  </ol>