使用文本框过滤绑定到acces数据库的列表框

Question

I'm pretty new in c#, taking lessons but with what i'm trying to do i know that i'm way ahead of schedule. I have a form with a listbox and a textbox. this is how I populate the listbox

private void Centrale_Gegevens_Load(object sender, EventArgs e)
    try
    {
        OleDbConnection verbinding = new OleDbConnection();
        verbinding.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=E:\Het Vlaamse Kruis\Het Vlaamse Kruis\data\Patienten.accdb; Jet OLEDB:Database Password=internet;";
        verbinding.Open();
        OleDbCommand combo = new OleDbCommand();
        combo.Connection = verbinding;
        string query = "select NaamPatient from tbl_Patient";
        combo.CommandText = query;
        OleDbDataReader reader = combo.ExecuteReader();
        while (reader.Read())
        {
            lstBox.Items.Add(reader["NaamPatient"]);
        }
        verbinding.Close();

    }
    catch (Exception ex)
    {
        MessageBox.Show("Error" + ex);
    }
}

the listbox is in that way populated with names of persons. The textbox named textbox1 is what i want to use to filter the listbox.

This is what i got sofare, but it doesn't work.

private void textBox1_TextChanged(object sender, EventArgs e)
{
    OleDbConnection verbinding = new OleDbConnection();
    verbinding.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=E:\Het Vlaamse Kruis\Het Vlaamse Kruis\data\Patienten.accdb; Jet OLEDB:Database Password=internet;";
    verbinding.Open();
    OleDbCommand cmd = new OleDbCommand();
    cmd.CommandType = CommandType.Text;
    cmd.CommandText = "select * from tbl_Patienten where NaamPatient like '" + textBox1.Text + "%' ";
    cmd.ExecuteNonQuery();
    DataTable dt = new DataTable();
    OleDbDataAdapter da = new OleDbDataAdapter(cmd);
    da.Fill(dt);
    lstBox.DataSource = dt;
    lstBox.DisplayMember = "NaamPatient";
    verbinding.Close();
}

I have red almost everything I can find on the net about it, bus no mather what i do, I can't get it to work. How can I get if I type A in the textbox that the listbox shows all the names beginning with A, And if I type AB that the listbox shows everything beginning with AB etc. Thanks in advance

Answer 1

Firstly, in Centrale_Gegevens_Load, table's name is tbl_Patient but in textBox1_TextChanged, it is tbl_Patienten. Secondly,Connection property has not been initialized. you must insert this: cmd.Connection = verbinding; after initializing the cmd;

 OleDbCommand cmd = new OleDbCommand();
cmd.Connection = verbinding;

Sorry for my bad English.