How to add edited date automatically to datetimepicker? - vb.net

Question

I want to make the time will fill automatically in Datetimepicker when I edit the price of my product. So, it can compare to the date of buying. So, I decided to use on_update_current_timestamp in MySQL database. My problem is how to convert a string into a date in Datagridview. Because when I was press the edit button it works but for the add button it's getting an error unable to convert MySQL date/time Is it have any solution to achieve my goal. If yes can u explain it. Thank u
Public Sub disp_data()
cmd = conn.CreateCommand()
cmd.CommandType = CommandType.Text
cmd.CommandText = "select * from produk"
cmd.ExecuteNonQuery()
Dim dt As New DataTable()
Dim da As New MySqlDataAdapter(cmd)
da.Fill(dt)
DataGridView1.DataSource = dt
End Sub
Private Sub tambah_btn_Click(sender As Object, e As EventArgs) Handles tambah_btn.Click
cmd = conn.CreateCommand()
cmd.CommandType = CommandType.Text
cmd.CommandText = $"insert into produk values('{kode.Text}','{nama.Text}','{harga.Text}','{DateTimePicker1.Value.ToString("dd/mm/yyyy")}')"
cmd.ExecuteNonQuery()
kode.Text = ""
nama.Text = ""
harga.Text = ""
disp_data()
MessageBox.Show("Data berhasil ditambahkan")
End Sub

Answer 1

You can do it (and it's better) like this:
'...
cmd = conn.CreateCommand()
cmd.CommandType = CommandType.Text
cmd.CommandText = "insert into produk values (#kode,#nama,#harga,#date)"
cmd.Parameters.AddWithValue("#kode", kode.Text)
cmd.Parameters.AddWithValue("#nama", nama.Text)
cmd.Parameters.AddWithValue("#harga", harga.Text)
cmd.Parameters.AddWithValue("#date", DateTimePicker1.Value.Date)
cmd.ExecuteNonQuery()
'...
let me know if it solves it, or if some adjustments are needed