如何使用标记属性移除动态添加的控件

Question

我有一个窗口窗体有一个按钮，当按钮被点击时，它动态生成控件，也有一个按钮被添加，这样它就会删除在行的控件，意味着在按钮旁边，当按钮被点击时，一行控件将被删除。我的代码是

int c = 0;
        private void button1_Click(object sender, EventArgs e)
        {
            int v;
            v = c++;
            panel1.VerticalScroll.Value = VerticalScroll.Minimum;

            Button btn = new Button();
            btn.Name = "btn" + v;
            btn.Text = "Remove";
            btn.Location = new Point(750, 5 + (30 * v));
            btn.Click += new EventHandler(btn_Click);

            ComboBox combo = new ComboBox();
            combo.Name = "combobox" + v;
            combo.Location = new Point(30, 5 + (30 * v));
            combo.Tag = btn;

            ComboBox combo2 = new ComboBox();
            combo2.Name = "combobox2" + v;
            combo2.Location = new Point(170, 5 + (30 * v));
            combo2.Tag = btn;

            TextBox txt = new TextBox();
            txt.Name = "txtbx" + v;
            txt.Location = new Point(300, 5 + (30 * v));
            txt.Tag = btn;

            TextBox txt2 = new TextBox();
            txt2.Name = "txtbx2" + v;
            txt2.Location = new Point(450, 5 + (30 * v));
            txt2.Tag = btn;

            TextBox txt3 = new TextBox();
            txt3.Name = "txtbx3" + v;
            txt3.Location = new Point(600, 5 + (30 * v));
            txt3.Tag = btn;

            panel1.Controls.Add(combo);
            panel1.Controls.Add(btn);
            panel1.Controls.Add(txt);
            panel1.Controls.Add(combo2);
            panel1.Controls.Add(txt2);
            panel1.Controls.Add(txt3);   
        }
        private void btn_Click(object sender, EventArgs e)// this is the dynamically added button's event which will remove the combobox and textbox
        {
            Button btnh = sender as Button;
            foreach (Control item in panel1.Controls.OfType<TextBox>())
            {
                if (item.Tag == sender || item == sender)
                    panel1.Controls.Remove(item);
            }
            foreach (Control item in panel1.Controls.OfType<ComboBox>())
            {
                if (item.Tag == sender || item == sender)
                    panel1.Controls.Remove(item);
            }
            panel1.Controls.Remove(btnh);
        }

我的错误是什么，但问题是它dosnt删除所有的控件，它留下控件，我不知道什么问题，我的代码简单容易，但我不知道哪里缺乏

Answer 1

问题是在循环遍历集合时正在移除项。在这种情况下，foreach-statement可能会跳过项。首先将要删除的项存储在列表中：

List<Control> toBeRemoved = panel1.Controls
    .Cast<Control>()
    .Where(c => c.Tag == sender)
    .ToList();
foreach (Control c in toBeRemoved) {
    panel1.Controls.Remove(c);
}

如果向后循环，也可以轻松地在循环中移除：

for (int i = panel1.Controls.Count - 1; i >= 0; i--) {
    if (panel1.Controls[i].Tag == sender) {
        panel1.Controls.RemoveAt(i);
    }
}