Unable to cast custom listviewitem class in vb.net - vb.net

Question

This is a followup question to another question I asked earlier. I thought I had everything I needed, but I'm running into another issue. I'm trying to use a custom listviewitem class that attaches additional information to a lisview item. Here is the class:
Public Class albumListViewItem
Inherits ListViewItem
Public hash As String
Public id As Integer
Public provider As String
Public providerID As String
Public providerURL As String
Public providerArtistID As String
Public albumName As String
Public albumType As String
Public numTracks As Integer
Public imageURLs() As String
Public genres() As String
Public styles() As String
Public label As String
Public year As String
Public country As String
Public rating As String
Public editorsPick As Boolean
Public sampleStreamURL As String
Public providerReview As String
End Class
When I try to cast a listviewitem to my custom class like this:
Dim albumItem As albumListViewItem = CType(lsvHidden.items.item(0), albumListViewItem)
I get the following error, "Unable to cast object of type 'System.Windows.Forms.ListViewItem' to type 'AudioMatic.albumListViewItem'."
What am I missing here?

Answer 1

From your previous question and this one, I think a better fit for your problem would be to use a regular ListViewItem and store the accessory information in ListViewItem.Tag
You can do
Dim listViewItem As New ListViewItem("SomeText")
Dim albumInfo As New albumListViewItem()
albumInfo.albumName = "SomeAlbum"
...
listViewItem.Tag = albumInfo
listView1.Items.Add(listViewItem)
and then retrieve it like this
Dim selectedItem As ListViewItem = listView1.SelectedItems(0).Item
Dim alubmInfo As albumListViewItem = TryCast(selectedItem.Tag, alubmListViewItem)
Dim albumName as String = albumInfo.albumName
see if this solution will work for you.

Answer 2

If you step through the code and watch the variable "lsvHidden.items.item(0)" you should be able to first tell if it is in fact of type "albumListViewItem" or something else. Are you sure it was albumListViewItem that was added to the list in the first place?
Some alternatives to what you are doing;
1. You can implement an object and store it in the tag of the ListViewItem.
2. The following article seems to describe another approach of adding Columns to the listview to allow storing extra information on the listview itself; http://www.codeproject.com/KB/list/ListViewExtendedItem.aspx
I can appreciate your situation as I would have expected that to work. And I can see advantages and reasons for doing it that way as well. Not sure if the code project sample is adaptable to what you need, so you'll need to review the concept.

Answer 3

The working code:
Public Class albumListViewItem
Inherits ListViewItem
Public hash As String
Public id As Integer
Public provider As String
Public providerID As String
Public providerURL As String
Public providerArtistID As String
Public albumName As String
Public albumType As String
Public numTracks As Integer
Public imageURLs() As String
Public genres() As String
Public styles() As String
Public label As String
Public year As String
Public country As String
Public rating As String
Public editorsPick As Boolean
Public sampleStreamURL As String
Public providerReview As String
End Class
Storing information using listviewitem.tag:
Dim listViewItem As New ListViewItem("SomeText")
Dim albumItem As New albumListViewItem
albumItem.albumName = "Test Album"
albumItem.id = "testid"
albumItem.Text = albumItem.albumName
albumItem.year = "2011"
albumItem.numTracks = 10
'....
listViewItem.Tag = albumItem
'add viewable items to listview
albumItem.SubItems.Add(albumItem.year)
albumItem.SubItems.Add(albumItem.numTracks)
'....
ListView1.Items.Add(albumItem)
Reading the information that was previously stored:
Dim albumInfo As albumListViewItem = CType(ListView1.SelectedItems(0), albumListViewItem)
Dim id as string = alumInfo.id