Excel sheet will upload but not store in database using Asp

using System;

using System.Collections.Generic;

using System.Data;

using System.Data.OleDb;

using System.IO;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using asthaModel;

public partial class _Default : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

PopulateData();

lblmessage.Text = "Current Database Data";

}

}

private void PopulateData()

{

using (asthaexcel1 ae = new asthaexcel1())

{

gvdata.DataSource = ae.information.ToList();

gvdata.DataBind();

}

}

protected void btnimport_Click(object sender, EventArgs e)

{

if (FileUpload1.PostedFile.ContentType == "application/vnd.ms-excel" || FileUpload1.PostedFile.ContentType == "application/vnd.openformats-officedocument.spreadsheetml.sheet")

{

try

{

string filename = Path.Combine(Server.MapPath("~/Styles"), Guid.NewGuid().ToString() + Path.GetExtension(FileUpload1.PostedFile.FileName));

FileUpload1.PostedFile.SaveAs(filename);

string constring = "";

string ext = Path.GetExtension(FileUpload1.PostedFile.FileName);

if (ext.ToLower() == ".xls")

{

constring = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source" + filename + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\""; ;

}

else

{

constring = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source" + filename + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";

}

string query = "Select [id],[studentname],[cource],[rollno],[password],[email],[contact] from [Sheet1$] ";

OleDbConnection con = new OleDbConnection(constring);

if (con.State == System.Data.ConnectionState.Closed)

{

con.Open();

}

OleDbCommand cmd = new OleDbCommand(query, con);

OleDbDataAdapter da = new OleDbDataAdapter(cmd);

DataSet ds = new DataSet();

da.Fill(ds);

da.Dispose();

con.Close();

con.Dispose();

using (asthaexcel1 ae = new asthaexcel1())

{

foreach (DataRow dr in ds.Tables[0].Rows)

{

string id = dr["id"].ToString();

var v = ae.information.Where(a => a.id.Equals(id)).FirstOrDefault();

if (v != null)

{

v.studentname = dr["studentname"].ToString();

v.cource = dr["cource"].ToString();

v.rollno = dr["rollno"].ToString();

v.password = dr["password"].ToString();

v.email = dr["email"].ToString();

v.contact = dr["contact"].ToString();

}

else

{

ae.information.Add(new information

{

id = dr["id"].ToString(),

studentname = dr["studentname"].ToString(),

cource = dr["cource"].ToString(),

rollno = dr["rollno"].ToString(),

password = dr["password"].ToString(),

email = dr["email"].ToString(),

contact=dr["contact"].ToString()

});

}

}

ae.SaveChanges();

}

PopulateData();

lblmessage.Text = "Successfully data imported";

}

catch (Exception)

{

throw;

}

}

}

}

ae.information.Add(new information

{

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