Building secure and robust web forms can be a difficult process because of the numerous different issues that need to be tracked and controlled. Once such issue is the default button on your form. Typically a user will fill out your web form and hit the enter button at the end to submit the form. In legacy ASP applications, the submit button on your form was the default button. With Asp.Net, you need to specify the button that is to be captured. The best way to handle this capture is to place your data entry form within a panel on the page and set the DefaultButton property to the id if your submit button.

Example:

<asp:Panel DefaultButton="IdOfYourButton" id="pnlStepOne" runat="server">

 </asp:Panel>