title: No definition for 'DisplayBox_TextChanged'
body: <pre><code>Compilation Error 
  Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. 
  
  Compiler Error Message: CS1061: 'ASP.calculator_aspx' does not contain a definition for 'DisplayBox_TextChanged' and no extension method 'DisplayBox_TextChanged' accepting a first argument of type 'ASP.calculator_aspx' could be found (are you missing a using directive or an assembly reference?)
  
  Source Error:enter code here
  
  Line 18:     &lt;tr&gt;
  Line 19:         &lt;td colspan="5"&gt;
  Line 20:             &lt;asp:TextBox ID="DisplayBox" runat="server" 
  Line 21:                 ontextchanged="DisplayBox_TextChanged" Width="268px"&gt;&lt;/asp:TextBox&gt;
  Line 22:         &lt;/td&gt;
  </code></pre>
  
  
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.IO;
  using System.Web;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  
  public partial class calculator : System.Web.UI.Page
  {
      protected void Page_Load(object sender, EventArgs e)
      {
  
      }
  }
  </code></pre>