所以我用如下复选框进行了简单的搜索：

这是你的密码 sort 按钮：

private void sort_btn_Click(object sender, EventArgs e)
        {
            if (cntr_check.Checked == true && pos_check.Checked == true)
            {
                var query = from o in this.leodata.main
                            where o.country.Contains(cntr_combo.Text) && o.position.Contains(pos_combo.Text) && o.price <= price_bar.Value
                            select o;
                mainBindingSource.DataSource = query.ToList();
            }
            else if (cntr_check.Checked == true && pos_check.Checked == false)
            {
                var query = from o in this.leodata.main
                            where o.country.Contains(cntr_combo.Text) && o.price <= price_bar.Value
                            select o;
                mainBindingSource.DataSource = query.ToList();
            }
            else if (cntr_check.Checked == false && pos_check.Checked == true)
            {
                var query = from o in this.leodata.main
                            where o.position.Contains(pos_combo.Text) && o.price <= price_bar.Value
                            select o;
                mainBindingSource.DataSource = query.ToList();
            }
            else
            {
                var query = from o in this.leodata.main
                            where o.price <= price_bar.Value
                            select o;
                mainBindingSource.DataSource = query.ToList();
            }

        }

现在我需要做一个高级搜索：

我试着这样做：

private void button1_Click(object sender, EventArgs e)
        {
            if (spain_check.Checked == true)
            {
                var query = from o in this.leodata.main
                            where o.country.Contains(spain_check.Text)
                            select o;
                mainBindingSource.DataSource = query.ToList();
            }
            if (france_check.Checked == true)
            {
                var query = from o in this.leodata.main
                            where o.country.Contains(france_check.Text)
                            select o;
                mainBindingSource.DataSource = query.ToList();
            }
        }

哪里 spain_check 以及 france_check 是我的复选框。我有一个想法，我会检查每一个复选框，如果 Checked == true 然后我将从mysql添加新行。但它不断更新我的表，而不是添加新行。
我该怎么做？