the 'username' does not exist in the current context
<p>I am making a Login Page with ASP.Net using C#... and i have put my html code in <strong>Login.aspx</strong> page . that contains a textbox named username but when I give reference of my textbox in Login.aspx.cs to make the validations on this text box ... as </p>

<pre><code>if(string.IsNullOrEmpty(username.Text))
{
...
...
}
</code></pre>

<p>i am getting an error that is saying ...-<code>"The 'username' doesn't exist in the current context"</code>...... 
how can i get rid of this error .... it is making me mas .... Help will be appreciable towards this error ... please help me .... </p>

<pre><code>&lt;%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="Login.aspx.cs" Inherits="Login" %&gt; 
&lt;asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent"&gt; &lt;/asp:Content&gt; 
&lt;asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent"&gt;
</code></pre>
