从datagridview C＃中删除数据库中的一行

Question

I'm trying to remove an entry from both the datagridview and the database. I got it so it removes the row from the data grid view but it fails to delete it also from the database. Here is my code I have in place:

  private void listBtn_Click(object sender, EventArgs e)
  {
        MySqlDataAdapter mysqldatadapter = new MySqlDataAdapter("select id, username from members ORDER BY id", new MySqlConnection(conn.connectionString));

        mysqldatadapter.Fill(ds);

        dataGridView.DataSource = ds.Tables[0];

        listBtn.Enabled = false;
  }


  private void btnDelete_Click(object sender, EventArgs e)
  {
        using (MySqlConnection dbConn = new MySqlConnection(conn.connectionString))
        {
            dbConn.Open();

            for (int i = 0; i < dataGridView.Rows.Count; i++)
            {
                DataGridViewRow row = dataGridView.Rows[i];

                if (row.Selected == true)
                {
                    dataGridView.Rows.RemoveAt(i);

                    MySqlCommand cmd = dbConn.CreateCommand();
                    cmd.CommandText = "DELETE FROM members WHERE id = " + i;

                    try
                    {
                        cmd.ExecuteNonQuery();
                    }
                    catch (MySqlException ex)
                    {
                        MessageBox.Show(ex.Message);
                    }
                }
            }

            dbConn.Close();
        }
  }

I'm at a loss concerning this, any help would be appreciated.

Thanks!

Update - Is there a way to grab the value of individual cells to pass to the mysql command? For instance, grabbing the id?

Answer 1

Your values for i probably don't match the id fields in the member table.

You probably need to change this line:

cmd.CommandText = "DELETE FROM members WHERE id = " + i;

to

cmd.CommandText = "DELETE FROM members WHERE id = " + row.cells[id.Index].ToString();