//For Reading excel sheet name and mount into combobox
private void btnbrows_Click(object sender, EventArgs e)
        {
            if (Opendialog.ShowDialog() == DialogResult.OK)
            {
                currentfilename = Opendialog.FileName;
                tbfilepath.Text = currentfilename;

                //Excel importing function
                string conStr = "Provider=Microsoft.Jet.OLEDB.4.0;" +
                "Data Source=" + tbfilepath.Text.ToString() + ";Extended Properties=Excel 8.0;";
                con = new OleDbConnection(conStr);


                con.Open();
                dt = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);

               if (dt == null)
               {
                   MessageBox.Show("no shhet found");;
               }
               string[] excelSheetNames = new string[dt.Rows.Count];
               int i = 0;
               int c = 0;

               foreach (DataRow row in dt.Rows)
               {
                   excelSheetNames[i] = row[c].ToString();
                   i++;
                   c++;
               }
               for (int s = 0; s < excelSheetNames.Length; s++)
               {
                   comboBox1.Items.Add(excelSheetNames[s].ToString());
               }
                      
            }

string constr= ConfigurationManager.AppSettings["dbpath"];
            string query="SELECT * INTO temp FROM OPENROWSET('Microsoft.Jet.OLEDB.4.0','Excel 8.0;Database='"+tbfilepath.Text+"','SELECT * FROM [Sheet2$]')";
            SqlConnection conn=new SqlConnection(constr);
            conn.Open();
            SqlCommand cmd = new SqlCommand(query, conn);
            SqlDataReader dr = cmd.ExecuteReader();//findng error in this line
            dr.Read();
            MessageBox.Show("done");
            conn.Close();