Hi,
Firstly, please make sure the Session.Add method is executed and there are values in TextBoxs. You can insert Breakpoint to validate them during debugging session.
For testing, you can try to run the following code and see whether you can get value from Session.
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
Session.Add("Name", "Leo");
}
protected void Button1_Click(object sender, EventArgs e)
{
Response.Write("Name is "+(string)Session["Name"]);
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:button ID="Button1" runat="server" Text="Show Session value" OnClick="Button1_Click" /></div>
</form>
</body>
</html>
Please also make sure the Session is not cleared before you try to access it.
I look forward to receiving your test results.