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问题描述
嘿.我有以下代码填充我的列表框
Hey. I've got the following code that populates my list box
UsersListBox.DataSource = GrpList;
但是，在填充该框后，默认选择列表中的第一项，并触发选择的索引已更改"事件.如何防止在填充列表框后立即选择项目，或者如何防止触发事件?
However, after the box is populated, the first item in the list is selected by default and the "selected index changed" event fires. How do I prevent the item from being selected right after the list box was populated, or how do I prevent the event from firing?
谢谢
推荐答案
为了防止事件触发，这里有两个我过去使用过的选项:
To keep the event from firing, here are two options I have used in the past:
在设置 DataSource 时取消注册事件处理程序.
Unregister the event handler while setting the DataSource.
UsersListBox.SelectedIndexChanged -= UsersListBox_SelectedIndexChanged;
UsersListBox.DataSource = GrpList;
UsersListBox.SelectedIndex = -1; // This optional line keeps the first item from being selected.
UsersListBox.SelectedIndexChanged += UsersListBox_SelectedIndexChanged;
创建一个布尔标志以忽略该事件.
Create a boolean flag to ignore the event.
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;
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