删除 CheckedListBox SelectedIndexChanged 上的动态文本框 [关闭]

Question

当我检查 CheckBoxList Items 时，会添加动态 texbox。但是在未选中时，我想删除特定的文本框。该代码在添加文本框时运行良好，但在删除时给了我例外。任何帮助都会很棒。

我的代码：

 iy = 0;
 private void checkedListBox_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (load == false)
        {
            return;
        }
            PackingDetails pd = new PackingDetails();
            var txt = new TextBox();
            for (iy = 0; iy < checkedListBox1.Items.Count; iy++)
            if (checkedListBox1.GetItemChecked(iy))
            {



                    txt.Name = iy.ToString();
                    txt.Text = iy.ToString();
                    txt.Location = new Point(23, 32 + (iy * 28));
                    txt.Visible = true;
                    this.Controls.Add(txt);
                    break;

            }

            else if (checkedListBox1.GetItemCheckState(iy) == CheckState.Unchecked)
            {
                foreach (TextBox t in this.Controls)
                {
                    if (t.Name == iy.ToString())

// 如果条件是最上面的文本框而不是点击的文本框被删除，我跳过这里。

                    {
                        this.Controls.Remove(t);
                        t.Dispose();
                        break;
                    }
                }

                break;
            }
    } 

或

我也试过了

  int iy = 0;
    private void checkedListBox1_ItemCheck(object sender, ItemCheckEventArgs e)
    {
       TextBox txt = new TextBox();
        panel1.VerticalScroll.Value = VerticalScroll.Minimum;
        if (e.NewValue == CheckState.Checked)
        {
            txt.Name = iy.ToString();
            txt.Text = iy.ToString();
            txt.Location = new Point(23, 32 + (iy * 28));
            txt.Visible = true;
            this.Controls.Add(txt);
            count = iy;
            iy++;

        }
        else
        {
            foreach (Control control in this.Controls)
            {
                if (control is TextBox)
                {
                   // here it deletes the topmost textbox but not the clicked one. Here if I used if condition like control.Name == iy.ToString() Nothing happens
                        this.Controls.Remove(control);
                        control.Dispose();
                        break;

                }
            }
        }
    }

Answer 1

this.Controls 会有多个控件：

 else if (checkedListBox1.GetItemCheckState(iy) == CheckState.Unchecked)
        {
            foreach (Control con in this.Controls)
            {
                if(con is TextBox)
                {
                    if (t.Name == iy.ToString())
                    {
                      this.Controls.Remove(t);
                      t.Dispose();
                      break;
                    }
                }
            }

            break;
        }

另外，如果它不起作用，请调试您的代码并查看控件是如何流动的

Answer 2

假设我猜到了错误的正确来源：

 foreach (TextBox t in this.Controls)
 {
       if (t.Name == iy.ToString())
       {
            this.Controls.Remove(t);
            t.Dispose();
            break;
       }
 }

可能可能工作，但也可能可能失败。不能仅仅假设this.Controls 中的所有Controls 都属于TextBox 类型。请注意，this.Controls 将返回特定上下文中的所有 Controls (this)。

解决方案是检查它是否为TextBox：

    foreach (var control in this.Controls)
    {
        if (control is TextBox)
        {
            if (t.Name != null && t.Name == iy.ToString())
            {
                this.Controls.Remove(t);
                t.Dispose();
                break;
            }
        }
    }

Answer 3

将CheckOnClick 设置为True of CheckBoxList ..

    private void checkedListBox1_SelectedIndexChanged(object sender, EventArgs e)
    {

        for (iy = 0; iy < checkedListBox1.Items.Count; iy++)
        {
            var item = checkedListBox1.Items[iy];
            string ctlName = item.ToString();
            Control txt = null;
            if (checkedListBox1.GetItemChecked(iy))
            {
                txt = FindControl(ctlName);
                if (txt != null)
                {
                    continue;
                }

                txt = new TextBox();
                txt.Name = ctlName;
                txt.Text = ctlName;
                txt.Location = new Point(150, 32 + (iy * 28));
                txt.Visible = true;
                this.Controls.Add(txt);                    
            }
            else if (checkedListBox1.GetItemCheckState(iy) == CheckState.Unchecked)
            {
                txt = FindControl(ctlName);
                if (txt==null)
                {
                    continue;
                }
                this.Controls.Remove(txt);
                txt.Dispose();                    
            }
        }


    }

    Control FindControl(String ctlName)
    {
        for (int i = 0; i < this.Controls.Count; i++)
        {
            if (this.Controls[i].Name==ctlName)
            {
                return this.Controls[i];
            }
        }

        return null;
    }