从asp.net列表框中获取所有选择项

Anyone know of a smooth way to get all of the selected items in a listbox control by using extension methods?

有人知道用扩展方法在列表框控件中获取所有选定项的平滑方法吗?

And, please, spare me the argument of it's irrelevant as to how one gets such a list because in the end everything uses a loop to iterate over the items and find the selected ones anyway.

还有，拜托，别跟我说一个人如何得到这样一个列表是无关的，因为最终所有东西都使用一个循环来遍历这些项并找到所选的项。

3 个解决方案

#1

var selected = yourListBox.Items.GetSelectedItems();
//var selected = yourDropDownList.Items.GetSelectedItems();
//var selected = yourCheckBoxList.Items.GetSelectedItems();
//var selected = yourRadioButtonList.Items.GetSelectedItems();

public static class Extensions
{
    public static IEnumerable<ListItem> GetSelectedItems(
           this ListItemCollection items)
    {
        return items.OfType<ListItem>().Where(item => item.Selected);
    }
}

#2

Extension method:

扩展方法:

public static List<ListItem> GetSelectedItems(this ListBox lst)
{
    return lst.Items.OfType<ListItem>().Where(i => i.Selected).ToList();
}

You can call it on your listbox like:

你可以在你的列表框中这样命名:

List<ListItem> selectedItems = myListBox.GetSelectedItems();

You could also do the conversion using a 'Cast' on the list box items like:

你也可以在列表框中使用“Cast”进行转换:

return lst.Items.Cast<ListItem>().Where(i => i.Selected).ToList();

Not sure which will perform better OfType or Cast (my hunch is Cast).

不确定哪一种会表现得更好(我的直觉是铸造)。

Edit based on Ruben's feedback for a generic ListControl method which would indeed make it much more useful extension method:

根据Ruben的反馈对一个通用的ListControl方法进行编辑，这确实会使它成为更有用的扩展方法:

public static List<ListItem> GetSelectedItems(this ListControl lst)
{
    return lst.Items.OfType<ListItem>().Where(i => i.Selected).ToList();
}

#3

Hello i've created one solution for this problem in this post using VB.NET:

你好，我在这篇文章中使用VB.NET为这个问题创建了一个解决方案:

Getting all selected values from an ASP ListBox

从一个ASP列表框中获取所有选择的值

This code below is the same as the link above:

下面的代码与上面的链接相同:

Public Shared Function getSelectedValuesFromListBox(ByVal objListBox As ListBox) As String
Dim listOfIndices As List(Of Integer) = objListBox.GetSelectedIndices().ToList()
Dim values As String = String.Empty

For Each indice As Integer In listOfIndices
    values &= "," & objListBox.Items(indice).Value
Next indice
If Not String.IsNullOrEmpty(values) Then
    values = values.Substring(1)
End If
Return values
End Function

I hope it helps.

我希望它有帮助。

#1

var selected = yourListBox.Items.GetSelectedItems();
//var selected = yourDropDownList.Items.GetSelectedItems();
//var selected = yourCheckBoxList.Items.GetSelectedItems();
//var selected = yourRadioButtonList.Items.GetSelectedItems();

public static class Extensions
{
    public static IEnumerable<ListItem> GetSelectedItems(
           this ListItemCollection items)
    {
        return items.OfType<ListItem>().Where(item => item.Selected);
    }
}

#2