C# update combobox with Database values

Question

Hello I have a database with drivers and combobox which is populated with the drivers. But when I add a new driver with a button Add Driver it's added only in Microsoft Acces table not in the combobox. And once I reload the program the new driver is deleted from the database. I also have connected the database in Data Source and I can edit the tables only from there(if I want to edit the combobox).

This is my connection with the database

private void Form1_Load(object sender, EventArgs e) { con = new OleDbConnection("Provider=Microsoft.ACE.Oledb.12.0;Data Source=transportDateBase.accdb"); cmd = new OleDbCommand(); con.Open(); cmd.Connection = con; string query = "SELECT Name FROM Drivers"; cmd.CommandText = query; OleDbDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { comboDriver.Items.Add(reader["Name"]); } con.Close();

and this is my Add Driver button:

OleDbConnection conn = new OleDbConnection(); conn.ConnectionString = ("Provider=Microsoft.ACE.Oledb.12.0;Data Source=transportDateBase.accdb");

        String Id = textID.Text;
        String Name = textName.Text;
        String Age = textAge.Text;
        String City = textCity.Text;

        OleDbCommand cmd = new OleDbCommand("INSERT into Drivers (Id, Name, Age, City) Values(@Id, @Name, @Age, @City)");
        cmd.Connection = conn;

        conn.Open();

        if (conn.State == ConnectionState.Open)
        {
            cmd.Parameters.Add("@Id", OleDbType.VarChar).Value = Id;
            cmd.Parameters.Add("@Name", OleDbType.VarChar).Value = Name;
            cmd.Parameters.Add("@Age", OleDbType.VarChar).Value = Age;
            cmd.Parameters.Add("@City", OleDbType.VarChar).Value = City;

            try
            {
                cmd.ExecuteNonQuery();
                MessageBox.Show("New Driver Added");
                conn.Close();
            }
            catch (OleDbException ex)
            {
                MessageBox.Show(ex.Source);
                conn.Close();
            }

Please help me to find my mistake..

Glynn Hurrell Glynn Hurrell · Accepted Answer · 2020-05-05T14:46:45

Just because you've added it to your database, doesn't mean anything else will happen.

You still need to update your UI.

Add this in after you have executed the query:

comboDriver.Items.Add(Name);

As an aside, you should also wrap the conn.Open() in a try catch as well

C# update combobox with Database values

1 Answers