c＃组合框根据另一个组合框的值过滤一个组合框

Question

I have 2 tables, product_items and category. And 2 combobox. I want filter another combobox, after selected category. Sorry for my bad english speak :), i tryed this 9h, and no solution get :/ My code how much i have writed.

DataSet ds = new DataSet();
            SqlDataAdapter da = new SqlDataAdapter("select itemid, itemname, pcatid from produkti_items_tab", TestConnection);
            da.Fill(ds, "FillDropDown");

            comboBox1.DataSource = ds.Tables["FillDropDown"].DefaultView;
            comboBox1.DisplayMember = "itemname";
            comboBox1.ValueMember = "itemid";

            //============================================
            DataSet ddd = new DataSet();
            SqlDataAdapter dada = new SqlDataAdapter("select pcatid, pcatname from produkti_cat_tab", TestConnection);
            dada.Fill(ddd, "FillDropDownzzz");

            comboBox2.DataSource = ddd.Tables["FillDropDownzzz"].DefaultView;
            comboBox2.DisplayMember = "pcatname";
            comboBox2.ValueMember = "pcatid";

But i dont know what i should write here:

    private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
    //how filter :/
}

Answer 1

Not sure, need to test this, but, the DataView binded to the first combobox has a RowFilter property.
Setting this property to the appropriate condition should remove the items that doesn't belong to the current category selected

if(comboBox2.SelectedValue != null)
{
    DataView dv = comboBox1.DataSource as DataView;
    dv.RowFilter = "pcatid = " + comboBox2.SelectedValue.ToString();
}