I know this is very OLD, but NOW myself Im struggling with helping a project that of course also is very old, but anyway, as they are using Web forms or ASPX, here is what I have for anyone having the same issue
1. when working with ASPx, I personally dont recommend to use
Form post/get method, because you will have to deal with same page
page load and check for fields there
Instead use a simple asp:button control to postback
and read info from there... I wrote lots more but my answer was chopped
Below, is the chunk of code MS uses there to post to same page code behind:
<div class="form-horizontal">
<h4>Create a new account</h4>
<hr />
<asp:ValidationSummary runat="server" CssClass="text-danger" />
<div class="form-group">
<asp:Label runat="server" AssociatedControlID="Email" CssClass="col-md-2 control-label">Email</asp:Label>
<div class="col-md-10">
<asp:TextBox runat="server" ID="Email" CssClass="form-control" TextMode="Email" />
<asp:RequiredFieldValidator runat="server" ControlToValidate="Email"
CssClass="text-danger" ErrorMessage="The email field is required." />
</div>
</div>
<div class="form-group">
<asp:Label runat="server" AssociatedControlID="Password" CssClass="col-md-2 control-label">Password</asp:Label>
<div class="col-md-10">
<asp:TextBox runat="server" ID="Password" TextMode="Password" CssClass="form-control" />
<asp:RequiredFieldValidator runat="server" ControlToValidate="Password"
CssClass="text-danger" ErrorMessage="The password field is required." />
</div>
</div>
<div class="form-group">
<asp:Label runat="server" AssociatedControlID="ConfirmPassword" CssClass="col-md-2 control-label">Confirm password</asp:Label>
<div class="col-md-10">
<asp:TextBox runat="server" ID="ConfirmPassword" TextMode="Password" CssClass="form-control" />
<asp:RequiredFieldValidator runat="server" ControlToValidate="ConfirmPassword"
CssClass="text-danger" Display="Dynamic" ErrorMessage="The confirm password field is required." />
<asp:CompareValidator runat="server" ControlToCompare="Password" ControlToValidate="ConfirmPassword"
CssClass="text-danger" Display="Dynamic" ErrorMessage="The password and confirmation password do not match." />
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<asp:Button runat="server" OnClick="CreateUser_Click" Text="Register" CssClass="btn btn-default" />
</div>
</div>
</div>