SqlConnection myconn;
SqlCommand mycomm;
s = WebConfigurationManager.ConnectionStrings["DatabaseConnectionString"].ConnectionString;
myconn = new SqlConnection(s);
myconn.Open();
mycomm = new SqlCommand("update insertmarks set first='" + TextBox1.Text + "', secound='" + TextBox2.Text + "', third='" + TextBox3.Text + "', fourth='" + TextBox5.Text + "', sixth='" + TextBox8.Text + "', seventh='" + TextBox9 + "', eighth='" + TextBox10.Text + "' where rollno='" + TextBox1.Text + "'", myconn);
SqlCommand cmd = new SqlCommand(m, myconn);
cmd.Parameters.AddWithValue("@first", TextBox2.Text);
cmd.Parameters.AddWithValue("@secound", TextBox3.Text);
cmd.Parameters.AddWithValue("@third", TextBox5.Text);
cmd.Parameters.AddWithValue("@fifth", TextBox8.Text);
cmd.Parameters.AddWithValue("@sixth", TextBox9.Text);
cmd.Parameters.AddWithValue("@total", TextBox10.Text);
cmd.Parameters.AddWithValue("@seventh", TextBox11.Text);
cmd.Parameters.AddWithValue("@eighth", TextBox12.Text);
cmd.Parameters.AddWithValue("@rollno", TextBox12.Text);
cmd.ExecuteNonQuery();
myconn.Close();
mycomm.ExecuteNonQuery();
}