Problem in saving XML data in database

What I understand from your question is you want to login into a ASP.NET website making use of a XML file. XML file contains login username-password information and you want to use it for authentication. If so, look at the following:
Video: How To Pull Data From An XML File Using ASP.NET[^]
Login using XML file in ASP.NET using C#[^]
Form Authentication in ASP.NET using XML[^]

Sample:
LoginData.xml

<?xml version="1.0" encoding="utf-8" ?>
<employee>
<User>
<username>bikrantsingh</username>
<password>bikrant123</password>
</User>
<User>
<username>anuragsingh</username>
<password>anurag</password>
</User>
<User>
<username>saurabh</username>
<password>saurabh123</password>
</User>
</employee>

Code behind:

protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
{
string username;
string pwd;
string CurrentUser = "";
string CurrentPwd = "";
bool LoginStatus = false;
username = Login1.UserName;
pwd = Login1.Password;
XmlDocument xmxdoc = new XmlDocument();
xmxdoc.Load(Server.MapPath("~/App_Data/Loginxml.xml"));
XmlNodeList xmlnodelist = xmxdoc.GetElementsByTagName("User");
foreach (XmlNode xn in xmlnodelist)
{
XmlNodeList xmlnl = xn.ChildNodes;
foreach (XmlNode xmln in xmlnl)
{
if (xmln.Name == "username")
{
if (xmln.InnerText == username)
{
CurrentUser = username;
}
}
if (xmln.Name == "password")
{
if (xmln.InnerText == pwd)
{
CurrentPwd = pwd;
}
}
}
if ((CurrentUser != "") & (CurrentPwd != ""))
{
LoginStatus = true;
}
}
if (LoginStatus == true)
{
Session["UserAuthentication"] = username;
Session.Timeout = 1;
Response.Redirect("Default2.aspx");
}
else
{
Session["UserAuthentication"] = "";
}
} 
}