ListBox和Datasource - 阻止选择第一个项目

Question

嘿.我有以下代码填充我的列表框

UsersListBox.DataSource = GrpList;

但是,在填充框后,默认情况下会选择列表中的第一个项目,并触发"选定的索引已更改"事件.如何在填充列表框后立即阻止选择项目,或者如何阻止事件触发？

谢谢

Answer 1

为了防止事件发生,以下是我过去使用过的两个选项:

1. 在设置DataSource时取消注册事件处理程序.

   UsersListBox.SelectedIndexChanged -= UsersListBox_SelectedIndexChanged;
   UsersListBox.DataSource = GrpList;
   UsersListBox.SelectedIndex = -1; // This optional line keeps the first item from being selected.
   UsersListBox.SelectedIndexChanged += UsersListBox_SelectedIndexChanged;
   

2. 创建一个布尔标志来忽略该事件.

   private bool ignoreSelectedIndexChanged;
   private void UsersListBox_SelectedIndexChanged(object sender, EventArgs e)
   {
       if (ignoreSelectedIndexChanged) return;
       ...
   }
   ...
   ignoreSelectedIndexChanged = true;
   UsersListBox.DataSource = GrpList;
   UsersListBox.SelectedIndex = -1; // This optional line keeps the first item from being selected.
   ignoreSelectedIndexChanged = false;
   

Answer 2

嗯，看起来像设置了ListBox.DataSource 后自动选中了第一个元素。其他解决方案是好的，但它们不能解决问题。这是我解决问题的方法：

// Get the current selection mode
SelectionMode selectionMode = yourListBox.SelectionMode;

// Set the selection mode to none
yourListBox.SelectionMode = SelectionMode.None;

// Set a new DataSource
yourListBox.DataSource = yourList;

// Set back the original selection mode
yourListBox.SelectionMode = selectionMode;