从Datagridview插入数据的正确方法。 C＃MySQL

Question

If i want to insert from datagridview into MYSQl Database, it injects into different columns instead of the correct columns.

My table looks like this :

id | visit_date | visitor_name | visit_address | visit_city | signin_time | vehicle_number | organization | visit_type | reason | id_type | person_visit | img | signout_time

Code looks like this :

private void confirmAppointmentToolStripMenuItem_Click(object sender, EventArgs e)
{
    string constring = ConfigurationManager.ConnectionStrings["MySQLDatabaseConnection"].ConnectionString;
    using (MySqlConnection con = new MySqlConnection(constring))
    {
        con.Open();
        string sql = "insert into vms_db.final_appointments(visit_date,visitor_name,signin_time,vehicle_number,organization,visit_type,reason,id_type,person_visit,img) values (@visit_date,@visitor_name,@signin_time,@vehicle_number,@organization,@visit_type,@reason,@id_type,@person_visit,@img)";

        using (MySqlCommand cmd = new MySqlCommand(sql, con))
        {
            try
            {
                for (int i = 0; i < dataGridView1.Rows.Count - 1; i++)
                {
                    cmd.Parameters.AddWithValue("@visit_date", System.DateTime.Now);
                    cmd.Parameters.AddWithValue("@visitor_name", dataGridView1.Rows[i].Cells[2].Value);
                    cmd.Parameters.AddWithValue("@visit_address", dataGridView1.Rows[i].Cells[3].Value);
                    cmd.Parameters.AddWithValue("@visit_city", dataGridView1.Rows[i].Cells[4].Value);
                    cmd.Parameters.AddWithValue("@signin_time", dataGridView1.Rows[i].Cells[5].Value);
                    cmd.Parameters.AddWithValue("@vehicle_number", dataGridView1.Rows[i].Cells[6].Value);
                    cmd.Parameters.AddWithValue("@organization", dataGridView1.Rows[i].Cells[7].Value);
                    cmd.Parameters.AddWithValue("@visit_type", dataGridView1.Rows[i].Cells[8].Value);
                    cmd.Parameters.AddWithValue("@reason", dataGridView1.Rows[i].Cells[9].Value);
                    cmd.Parameters.AddWithValue("@id_type", dataGridView1.Rows[i].Cells[10].Value);
                    cmd.Parameters.AddWithValue("@person_visit", dataGridView1.Rows[i].Cells[11].Value);
                    cmd.Parameters.AddWithValue("@img", dataGridView1.Rows[i].Cells[12].Value);
                    cmd.ExecuteNonQuery();
                    MessageBox.Show("Final Appointments Reserved, You may Exit Window", "Notification", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    Close();
                }
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }
    }
}

Now it doesn't insert into the correct columns. I got tempted, and since I want to be sure of what I am doing, I am asking if I can correctly insert into the database via this means :

cmd.Parameters.AddWithValue("@visitor_name", dataGridView1.Rows[i].Cells["visitor_name"].Value);
cmd.Parameters.AddWithValue("@visit_address", dataGridView1.Rows[i].Cells["visit_address"].Value);

Answer 1

Your code cannot work correctly because you use the same command for all rows but you continuosly add parameters without clearing them at each loop.
This will result in errors while adding the parameters in the second row or many records added with the same value.

You can write a better code defining the parameter once for all and then just changing the value inside the loop. And not use AddWithValue at all

using (MySqlCommand cmd = new MySqlCommand(sql, con))
{
    try
    {
        cmd.Parameters.Add("@visit_date", MySqlDbType.DateTime);
        cmd.Parameters.Add("@visitor_name", MySqlDbType.VarChar);
        .... // add all the other parameters here

        for (int i = 0; i < dataGridView1.Rows.Count - 1; i++)
        {
            cmd.Parameters["@visit_date"].Value = System.DateTime.Now;

            // You need to be sure about what column contains the 
            // visitor name. Here for example you take the value 
            // from the third column, not from the second one.
            cmd.Parameters["@visitor_name"].Value = dataGridView1.Rows[i].Cells[2].Value;
            ... again set the value at each loop for each parameter
            cmd.ExecuteNonQuery();
        }
    }
    catch(Exception ex)
    {
        MessageBox.Show(ex.ToString());
    }
}