Question

嘿。我有以下代码填充我的列表框

UsersListBox.DataSource = GrpList;

但是，填充此框后，默认情况下会选择列表中的第一项，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，或者如何防止事件被触发？

由于

Answer 1

为了防止事件被触发，以下是我过去使用过的两个选项：

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;

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

好吧，看起来在设置ListBox.DataSource之后会自动选择第一个元素。其他解决方案很好，但它们无法解决问题。这就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;

Answer 3

我使用以下内容，似乎对我有用：

List<myClass> selectedItemsList = dataFromSomewhere

//Check if the selectedItemsList and listBox both contain items
if ((selectedItemsList.Count > 0) && (listBox.Items.Count > 0))
{
   //If selectedItemsList does not contain the selected item at 
   //index 0 of the listBox then deselect it
   if (!selectedItemsList.Contains(listBox.Items[0] as myClass))
   {
      //Detach the event so it is not called again when changing the selection
      //otherwise you will get a Stack Overflow Exception
      listBox.SelectedIndexChanged -= listBox_SelectedIndexChanged;
      listBox.SetSelected(0, false);
      listBox.SelectedIndexChanged += listBox_SelectedIndexChanged;
   }
}

Answer 4

设置IsSynchronizedWithCurrentItem="False"和SelectedIndex=-1并且每件事都适合你

Answer 5

如果您只想清除所选值，可以在设置DataSource后使用ClearSelected。但如果你不希望事件发生，那么你将不得不使用约瑟夫的一种方法。

Answer 6

也许在DataSourceChanged中你可以检查SelectedIndex的状态，如果幸运的话你可以强迫SelectedIndex = -1。

ListBox和Datasource - 阻止选择第一个项目

6 个答案: