title: Filter / Iterate a List by values inside List C#
body: <p>Hello I am using c# in ASP.NET MVC Web.</p>
  
  <p>I have a list of object that contains different different data inside example:</p>
  
  <pre><code>List&lt;One&gt; obj = new List&lt;One&gt;();
  obj[0].studentname = "rahul";
  obj[0].rolenumber = "20";
  
  obj[1].studentname = "padhiyar";
  obj[1].rolenumber = "74";
  
  ...
  ...
  ...
  
  obj[max].studentname = "lastname of the student";
  obj[max].rolenumber = "his / her roll number";
  </code></pre>
  
  <p>I want to iterate this list and get another list which is sorted by role number which is string and some object may not have role number inside so how may I do this?</p>
  
  <p>Anyone have any idea?</p>