C# 删除过程中修改了Listbox项目集合；枚举操作不能执行

我必须将一个项目从一个列表框移动到另一个列表框，如上图所示

• >按钮将一个或多个选定项从listbox1移动到listbox2
• >>按钮将所有项目从listbox1移动到listbox2

---

• 您正在对集合进行迭代时对其进行修改。我没有IDE，但您可以尝试：

  protected void btn3_Click(object sender, EventArgs e)
  {
      lbltext.Visible = false;
      if (lstBoxAreaOfResponsibility2.Items.Count != 0)
      {
          lstBoxAreaOfResponsibility2.Items.Clear();
      }
      else
      {
          lbltext.Visible = true;
          lbltext.Text = "There Is No Item To Move";
      }
  }
  
  protected void btn4_Click(object sender, EventArgs e)
  {
      lbltext.Visible = false;
      if (lstBoxAreaOfResponsibility2.SelectedIndex >= 0)
      {
          ListItem itemToDelete = new ListItem();
          foreach (ListItem Item in lstBoxAreaOfResponsibility2.Items)
          {
              if (Item.Selected == true)
              {
                  itemToDelete = Item;
              }
          }
          lstBoxAreaOfResponsibility2.Items.Remove(itemToDelete);
      }
      else
      {
          lbltext.Visible = true;
          lbltext.Text = "Please select atleast one in Listbox2 to move";
      }
  }
  

  为了它的价值，有一个

  protected void btn3_Click(object sender, EventArgs e)
  {
      lbltext.Visible = false;
      if (lstBoxAreaOfResponsibility2.Items.Count != 0)
      {
          lstBoxAreaOfResponsibility2.Items.Clear();
      }
      else
      {
          lbltext.Visible = true;
          lbltext.Text = "There Is No Item To Move";
      }
  }
  
  protected void btn4_Click(object sender, EventArgs e)
  {
      lbltext.Visible = false;
      if (lstBoxAreaOfResponsibility2.SelectedIndex >= 0)
      {
          ListItem itemToDelete = new ListItem();
          foreach (ListItem Item in lstBoxAreaOfResponsibility2.Items)
          {
              if (Item.Selected == true)
              {
                  itemToDelete = Item;
              }
          }
          lstBoxAreaOfResponsibility2.Items.Remove(itemToDelete);
      }
      else
      {
          lbltext.Visible = true;
          lbltext.Text = "Please select atleast one in Listbox2 to move";
      }
  }