title: LINQ search by text
body: <p>I would like to do a linq, 
  "When the txtKeyword.Text is empty, the query will return all data, or else it will return the data that contains the txtKeyword.Text."</p>
  
  <pre><code>        var search = from a in Context.data
                       where txtKeyword.Text.Trim().Count() &gt; 0 ? a.Name.Contains(txtKeyword.Text.Trim()) : true
                       select a;
  </code></pre>
  
  <hr>
  
  <pre><code>Error:
  DbExpressionBinding requires an input expression with a collection ResultType.
  Parameter name: input
  </code></pre>
  
  <p>How can I achieve it?</p>