C# 将 ListView 项目投射到 List<string>？
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Cast ListView Items to List<string>?
提问by user2214609
How can I cast ListView.Itemsto a List<string>?
我怎样才能投射ListView.Items到 a List<string>？
This is what I tried:
这是我尝试过的：
List<string> list = lvFiles.Items.Cast<string>().ToList();
but I received this error:
但我收到了这个错误：
Unable to cast object of type 'System.Windows.Forms.ListViewItem' to type 'System.String'.
无法将“System.Windows.Forms.ListViewItem”类型的对象转换为“System.String”类型。
采纳答案by Jon Skeet
A ListViewItemCollectionis exactly what it sounds like - a collection of ListViewItemelements. It's nota collection of strings. Your code fails at execution time for the same reason that this code would fail at compile time:
AListViewItemCollection正是它听起来的样子 -ListViewItem元素的集合。它不是字符串的集合。您的代码在执行时失败的原因与此代码在编译时失败的原因相同：
ListViewItem item = lvFiles.Items[0];
string text = (string) item; // Invalid cast!
If you want a list of strings, each of which is taken from the Textproperty of a ListViewItem, you can do that easily:
如果你想要一个字符串列表，每个字符串都取自Texta的属性ListViewItem，你可以很容易地做到这一点：
List<string> list = lvFiles.Items.Cast<ListViewItem>()
.Select(item => item.Text)
.ToList();
回答by p.s.w.g
The Castmethod will essentially try to perform a box/unbox, so it will fail if the items in the list aren't already strings. Try this instead:
该Cast方法本质上将尝试执行装箱/拆箱，因此如果列表中的项目还不是字符串，它将失败。试试这个：
List<string> list = lvFiles.Items.Cast<ListViewItem>()
.Select(x => x.ToString()).ToList();
Or this
或这个
List<string> list = lvFiles.Items.Cast<ListViewItem>()
.Select(x => x.Text).ToList();
回答by Sriram Sakthivel
Try something like this
尝试这样的事情
List<string> list = lvFiles.Items.Cast<ListViewItem>().Select(x=> x.ToString()).ToList();
回答by Felipe Oriani
Try this using the Selectmethod:
使用以下Select方法试试这个：
for list text:
对于列表文本：
List<string> listText = lvFiles.Items.Select(item => item.Text).ToList();
for list values:
对于列表值：
List<string> listValues = lvFiles.Items.Select(item => item.Value).ToList();
Or maybe, for both:
或者，对于两者：
Dictionary<string, string> files = lvFiles.Items.ToDictionary(key => key.Value, item => item.Text);
