Upload Excel having 6500 rows into MSSQL database table

OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\testing.xlsx;Extended Properties='Excel 12.0 Xml;HDR=Yes;IMEX=1;'");
        OleDbCommand cmd = new OleDbCommand("select * from [Sheet1$]");
        if (conn.State == System.Data.ConnectionState.Open)
        {
            conn.Close();
        }
        conn.Open();
        OleDbDataAdapter adap = new OleDbDataAdapter(cmd);
        DataSet ds = new DataSet();
        adap.Fill(ds);
        this.GridView1.DataSource = ds.Tables[0].DefaultView;
        conn.Close();

string[] array2 = Directory.GetFiles(@"D:\doc", "*.xls");
 
foreach (string name in array2)
{
    string excelConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 8.0;HDR=YES;""";
    excelConnectionString=string.Format(excelConnectionString,name).Trim();
    
    Console.WriteLine(excelConnectionString);
    
    // Create Connection to Excel Workbook
    using (OleDbConnection connection =new OleDbConnection(excelConnectionString))
    {
        OleDbCommand command = new OleDbCommand("Select Field1,Field2,Field3 FROM [Sheet1$]", connection);
    
        connection.Open();
        
        // Create DbDataReader to Data Worksheet
        using (DbDataReader dr = command.ExecuteReader())
        {
            // SQL Server Connection String
            string sqlConnectionString = @"Data Source=Machine007\SQLEXPRESS;Initial Catalog=BankDB;Integrated Security=True";
    
            // Bulk Copy to SQL Server
            using (SqlBulkCopy bulkCopy =
                    new SqlBulkCopy(sqlConnectionString))
            {
                bulkCopy.DestinationTableName = "BankCodes";
                bulkCopy.WriteToServer(dr);
            }
        }
    }
 
}