Bulk Insert

I have solved the question using the codes by Satyapriya Nayak.

int i = 0;
List ChkedRow = new List();
for (i = 0; i <= dataGridView1.RowCount - 1; i++)
{
    if (Convert.ToBoolean(dataGridView1.Rows[i].Cells["id"].Value) == true)
    {
        ChkedRow.Add(i);
    }
}
if (ChkedRow.Count == 0)
{
    MessageBox.Show("En az bir checkbox seçiniz!");
    return;
}
foreach (int j in ChkedRow)
{
    try
    {
        if (conn.State == ConnectionState.Closed)
        {
            conn.Open();
        }
        var val1 = dataGridView1.Rows[j].Cells["isim"].Value;
        var val2 = dataGridView1.Rows[j].Cells["soyisim"].Value;
        OleDbCommand cmd = new OleDbCommand("select * from gezilistemiz25 where adi = '" + val1 + "' and soyadi=  '" + val2 + "' ", conn);
        OleDbDataReader dr = cmd.ExecuteReader();
        if (dr.Read())
        {
            MessageBox.Show(" '" + val1 + "' '" + val2 + "' isimli kisi veritabaninda kayitlidir. Mükerrer kayit yapilamaz. Lütfen ögrenci numarasini kontrol ediniz.");
        }
        else
        {
            var cmdText = @"INSERT INTO  gezilistemiz25 (adi, soyadi, cinsiyet, unvani) VALUES('" + dataGridView1.Rows[j].Cells["isim"].Value + "', '" + dataGridView1.Rows[j].Cells["soyisim"].Value + "', '" + dataGridView1.Rows[j].Cells["cinsiyet"].Value + "', '" + dataGridView1.Rows[j].Cells["unvan"].Value + "')";
            var command = new OleDbCommand(cmdText, conn);
            command.ExecuteNonQuery();
            conn.Close();
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}
MessageBox.Show("Kayitlar Basariyla eklendi!");

I am using OleDbconnection. OleDbBulkCopy gives error.. 

Hi ,

First, you must fetch all records on the selected index change event in Gridview.

After that follow the instructions below,

using (SqlConnection conn = new SqlConnection("your-connection-string"))
{
    using (SqlCommand command = new SqlCommand("", conn))
    {
        try
        {
            conn.Open();
            //Bulk insert into temp table
            using (SqlBulkCopy bulkcopy = new SqlBulkCopy(conn))
            {
                bulkcopy.BulkCopyTimeout = 660;
                bulkcopy.DestinationTableName = "Products_Temp";
                bulkcopy.WriteToServer(dt);
                bulkcopy.Close();
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.ToString());
        }
        finally
        {
            conn.Close();
            Console.WriteLine(list.Count + " Records updated");
        }
    }
}