why the event: comboBox_SelectedIndexChanged get trigered at form_load event?

Question

When i load a form that contains a combobox, i noticed that the comboBox_SelectedIndexChanged event is triggered, but i don't want to use that event at form load, what do you propose to avoid this problem.

I tried to stop it by setting a Boolean to false, and told to the comboBox_SelectedIndexChanged to execute only if the boolean equals true. of course after the form_load event finishes, I set the boolean to true, but that's not working.

Any help would be appreciated

here is the code :

 private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
                {
                    setprice(comboBox1, textBox1, textBox2, 0);


                }

---

 public void setprice(ComboBox combo, TextBox prix, TextBox qt, int num)
            {
                if (flag1[num] == 1)
                {
                    SqlDataReader reader = null;
                    try
                    {
                        SqlCommand command = mySqlConnection1.CreateCommand();
                        command.CommandText = "select prix_vente_ttc, prix_vente_ht from STK_PRODUITS_GENERIQUE where num_produit=" + combo.SelectedValue.ToString();
                        reader = command.ExecuteReader();
                        while (reader.Read())
                        {

                            prix_ttc[num] = Convert.ToDouble(reader.GetDecimal(0));
                            prix_ht[num] = Convert.ToDouble(reader.GetDecimal(1));
                            prix_htt[num] = prix_ht[num] * Convert.ToInt16(qt.Text);
                            //fact.forfait.setPrix_ht( prix_htt);
                            //fact.forfait.setTva(prix_ttct - prix_htt);

                            prix_ttct[num] = prix_ttc[num] * Convert.ToDouble(qt.Text);
                            prix.Text = Convert.ToString(prix_ttct[num]);
                        }
                        //textBox3_TextChanged(null, null);
                        // reader.Close();


                    }
                    catch (Exception excep)
                    {
                        MessageBox.Show(excep.Message); 
                        //if (reader != null) reader.Close();
                    }
                    if (reader != null) reader.Close();


                }
                flag1[num] = 1;
            }

---

private void vidangeform_Load(object sender, EventArgs e)
        {
            flag1[0] = 0;
            flag1[1] = 0;
            SqlDataReader reader = null;
            try
            {
                nextform = new filtreform();


                SqlCommand command = mySqlConnection1.CreateCommand();
                command.CommandText = "select designation, num_produit  from STK_PRODUITS_GENERIQUE where STK_PRODUITS_GENERIQUE.num_famille in (select num_famille from parametrage_vidange where parametrage_vidange.produit='forfait_vidange')";

                Dictionary<int, string> dict = new Dictionary<int, String>();
                reader = command.ExecuteReader();

                while (reader.Read())
                {

                    dict.Add(reader.GetInt32(1), reader.GetString(0));

                }
                comboBox1.DataSource = new BindingSource(dict, null);
                comboBox1.DisplayMember = "Value";
                comboBox1.ValueMember = "Key";
                reader.Close();

                command = mySqlConnection1.CreateCommand();
                command.CommandText = "select designation, num_produit  from STK_PRODUITS_GENERIQUE where STK_PRODUITS_GENERIQUE.num_famille in (select num_famille from parametrage_vidange where parametrage_vidange.produit='huile')";

                dict = new Dictionary<int, String>();
                reader = command.ExecuteReader();

                while (reader.Read())
                {

                    dict.Add(reader.GetInt32(1), reader.GetString(0));

                }
                comboBox2.DataSource = new BindingSource(dict, null);
                comboBox2.DisplayMember = "Value";
                comboBox2.ValueMember = "Key";
                reader.Close();
            }
            catch (Exception ep) { MessageBox.Show("problème de connexion avec le serveur ou resultat retourné nul. \n" + ep.Message); if(reader != null) reader.Close(); }



        }

Answer 1

SelectedIndexChanged is fired when you set the DataSource for the comboBox.

It is hard to come up with a clean way of managing events with WinForms, but what you could do is instead of subscribing to the event at design-time, you could subscribe to it after you set the dataSource:

• remove the event handler comboBox1_SelectedIndexChanged from your combobox events in design time

• add the following line at the end of your vidangeform_Load method:

  comboBox1.SelectedIndexChanged += comboBox1_SelectedIndexChanged;