访问不保存输入

我在Yt, Google等上查了一下。我尝试了5种解决方案，但一无所获。我把txt放到文本框，它显示在列表框中，但不去访问。

简而言之

 private void addAF_Click(object sender, EventArgs e)
    {

         if (aFInput.Text != "") {
            string q = "insert into AFs (AFNumber,SendDate,Notes) values ('"+aFInput.Text.ToString()+"','"+DateTime.Now+"', '"+notes.Text.ToString()+"')";
            dosomemagic(q);
            aFInput.Text = null;
        }
    }
    private void dosomemagic(String q)
    {
        try
        {
            cnn.Open();
            cmd.CommandText = q;
            cmd.ExecuteNonQuery();
            cnn.Close();
            loaddata();
        }
        catch (Exception e)
        {
            cnn.Close();
            MessageBox.Show(e.Message.ToString());
        }
    }
    private void ANLPA_Load(object sender, EventArgs e)
    {
        cnn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=AFdbB03.mdb;";
        cmd.Connection = cnn;
        loaddata();
    }
    private void loaddata()
    {
        AFList.Items.Clear();
        try
        {
            string q = "select * from AFs";
            cmd.CommandText = q;
            cnn.Open();
            dr = cmd.ExecuteReader();
            if (dr.HasRows)
            {
                while (dr.Read())
                {
                    AFList.Items.Add(dr[1].ToString());
                    keyList.Items.Add(dr[0].ToString());
                }
            }
            dr.Close();
            cnn.Close();
        }
        catch (Exception ex) 
        {
            cnn.Close();
            MessageBox.Show(ex.Message.ToString());
        }
    }