以编程方式从面板中删除控件

Question

我有一个名为pan_items的面板和两个名为btn_fresh和btn_next的按钮。我使用'fresh'来加载一组选项，'next'来改变选项。选项显示为radiobuttons，我以编程方式添加和删除。我的代码添加radiobutton控件没有问题，但当我尝试删除它时，它随机删除一些并留下一些。这是我的代码

private void btn_fresh_Click(object sender, EventArgs e)
    {
        this.index = 0;
        int i = 0;
        foreach (string str in options[index])
        {
            RadioButton rdb = new RadioButton();
            rdb.Text = str;
            rdb.Name = str + "_" + i++;
            rdb.Location = new Point(20, i * 20);
            pan_items.Controls.Add(rdb);
        }
        btn_fresh.Enabled = false;
        btn_next.Enabled = true;
    }

    private void btn_next_Click(object sender, EventArgs e)
    {
        foreach (Control ctrl in pan_items.Controls.OfType<RadioButton>())
        {
            if (((RadioButton)ctrl).Checked)
                MessageBox.Show(ctrl.Name + " " + ctrl.Text + " is checked!");
            pan_items.Controls.Remove(ctrl);
            this.Controls.Remove(ctrl);
            ctrl.Dispose();
        }
        this.index += 1;
        int i = 0;
        foreach (string str in options[index])
        {
            RadioButton rdb = new RadioButton();
            rdb.Text = str;
            rdb.Name = str + "_" + i++;
            rdb.Location = new Point(20, i * 20);
            pan_items.Controls.Add(rdb);
        }
        btn_previous.Enabled = true;
    }

有什么问题，如何纠正？

非常感谢，从重复的链接中得到了答案。这段代码工作

private void btn_next_Click(object sender, EventArgs e)
    {
        for (int j = pan_items.Controls.OfType<RadioButton>().Count() - 1; j >= 0; --j)
        {
            var ctrl = pan_items.Controls[j];
            if (((RadioButton)ctrl).Checked)
                MessageBox.Show(ctrl.Name + " " + ctrl.Text + " is checked!");
            pan_items.Controls.Remove(ctrl);
            this.Controls.Remove(ctrl);
            ctrl.Dispose();
        }
        this.index += 1;
        int i = 0;
        foreach (string str in options[index])
        {
            RadioButton rdb = new RadioButton();
            rdb.Text = str;
            rdb.Name = str + "_" + i++;
            rdb.Location = new Point(20, i * 20);
            pan_items.Controls.Add(rdb);
        }
        btn_previous.Enabled = true;
    }