Cast ListView Items to List<string>?

问题

How can I cast ListView.Items to a List<string>?

This is what I tried:

List<string> list = lvFiles.Items.Cast<string>().ToList();

but I received this error:

Unable to cast object of type 'System.Windows.Forms.ListViewItem' to type 'System.String'.

回答1:

A ListViewItemCollection is exactly what it sounds like - a collection of ListViewItem elements. It's not a collection of strings. Your code fails at execution time for the same reason that this code would fail at compile time:

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 Text property of a ListViewItem, you can do that easily:

List<string> list = lvFiles.Items.Cast<ListViewItem>()
                                 .Select(item => item.Text)
                                 .ToList();

回答2:

The Cast method 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:

List<string> list = lvFiles.Items.Cast<ListViewItem>()
                                 .Select(x => x.ToString()).ToList();

Or this

List<string> list = lvFiles.Items.Cast<ListViewItem>()
                                 .Select(x => x.Text).ToList();

回答3:

Try something like this

List<string> list = lvFiles.Items.Cast<ListViewItem>().Select(x=> x.ToString()).ToList();

回答4:

Try this using the Select method:

for list text:

List<string> listText = lvFiles.Items.Select(item => item.Text).ToList();

for list values:

List<string> listValues = lvFiles.Items.Select(item => item.Value).ToList();

Or maybe, for both:

Dictionary<string, string> files = lvFiles.Items.ToDictionary(key => key.Value, item => item.Text);

来源：https://stackoverflow.com/questions/17932873/cast-listview-items-to-liststring