din kommandotext måste också parametriseras
cmd.CommandText = " UPDATE incomingdeliveries SET Quantity = @iQuantity + Quantity"
cmd.Parameters.Add(New MySqlParameter("@iQuantity", txtQty.Text))
UPPDATERING 1
Using _conn As New MySqlConnection("connectionStr here")
Using _comm As New MySqlCommand()
With _comm
.Connection = _conn
.CommandText = "UPDATE incomingdeliveries SET Quantity = @iQuantity + Quantity"
.CommandType = CommandType.Text
.Parameters.AddWithValue("@iQuantity", txtQty.Text)
End With
Try
_conn.Open()
_comm.ExecuteNonQuery()
Catch ex As MySqlException
Msgbox(ex.Message.ToString())
End Try
End Using
End Using