防止用户取消选择列表框中的项目? [英] Prevent user from deselecting an item in a ListBox?

问题描述

我有一个 ListBox，里面有一堆项目.用户可以单击一个项目来编辑其内容.如何防止用户取消选择所有项目?即，用户不应选择任何内容.

I've got a ListBox with a bunch of items in it. The user can click an item to edit its contents. How do I prevent the user from deselecting all items? i.e., the user shouldn't be able to have nothing selected.

推荐答案

您的情况缺少一个案例，即当列表被清除时，您将重新选择列表中不再存在的项目.我通过添加额外的检查来解决这个问题.

There is a case missing in your situation, which is when the list is cleared you will reselect an item there is no longer on the list. I solve this by adding an extra check.

        var listbox = ((ListBox)sender);
        if (listbox.SelectedItem == null)
        {
            if (e.RemovedItems.Count > 0)
            {
                object itemToReselect = e.RemovedItems[0];
                if (listbox.Items.Contains(itemToReselect))
                {
                    listbox.SelectedItem = itemToReselect;
                }
            }
        }

然后我把这个放在一个行为中.

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