Writing an appointment application to study skills

I have a problem trying connect ASP .NET controls with my Visual C# code and I need to find out why.  All the directive are there.  The ASP controls are the same name and everything else looks fine just need to see if anyone can help.  I've seen people put class level variables in a Page_Loaded() but it would lock the feilds and I can't use them in later methods so first one is the ASP .NET page then the C# code-behind page.  
<div id="UserInput"> <asp:TextBox ID="txtDate" runat="server" CssClass="Entry"></asp:TextBox> <br /> <asp:TextBox ID="txtTime" runat="server" CssClass="Entry"></asp:T ...