title: How can I clear data in a GridView?
body: <p>I have 3 <code>GridViews</code> in my page.</p>
  
  <p>Using the <code>SelectedIndexChanged</code> event I put <code>GridView2</code> and <code>GridView3</code> data in <code>GridView1</code>
  but when I restart my application <code>GridView1</code> data is still persisted in browser.</p>
  
  <p>I used a session variable to store the data. How can I clear <code>GridView1</code></p>