ListView.Sort Trouble - Xtreme Visual Basic Talk

10-20-2006, 02:49 PM

ShadowWolf ShadowWolf is offline

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ListView.Sort Trouble

Hello,

I think I've managed to find a bug in the ListView control. When I tell the ListView to sort, it only sorts the first group (lv1.groups(0)) and leaves the other group unsorted. There doesn't seem to be a way to sort all groups so what do I do now?

10-20-2006, 08:13 PM

IUnknown

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Take a look at IComparer. I posted a link on a previous thread that has an example.

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10-21-2006, 08:28 AM

ShadowWolf ShadowWolf is offline

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Quote:

Originally Posted by IUnknown

Take a look at IComparer. I posted a link on a previous thread that has an example.

Ah I were hoping it could be done without that, just me missing something simple. I guess I'll make my own sorting function with IComparer then (I do not like copying). Thanks.

Edit: Manual sorting does not work on groups. The MS example does not use groups either (I wonder why

). Now, is it really impossible to sort all groups in a listview control?

Edit: Tried to put the items for the 2 groups into 2 separate listviews and sort them there before cloning the items to the visible listbox. This time there was no sorting in any of the groups. No matter how I copied the items it just wouldn't get them in the sorted order.

Last edited by ShadowWolf; 10-21-2006 at 10:00 AM.

10-21-2006, 10:56 AM

IUnknown

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What are groups? Can you post a short example of what you're trying to achieve.

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10-21-2006, 12:59 PM

ShadowWolf ShadowWolf is offline

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Quote:

Originally Posted by IUnknown

What are groups? Can you post a short example of what you're trying to achieve.

Code:

ListView1.Groups.Add("g1","Group 1")
ListView1.Groups.Add("g2","Group 2")

Dim LVI as ListViewItem

LVI = ListView1.Items.Add("Test 1")
LVI.Group = ListView1.Groups(0)
LVI = ListView1.Items.Add("Test 2")
LVI.Group = ListView1.Groups(1)

ListView1.Sort() 'This only sorts ListView1.Groups(0) and there is no way to set the "active" group.

Edit: What I'm trying to create is a listview with folders, sorted alphabetically at the top, and files below them, also sorted alphabetically. With groups you can separate these 2, the problem is that the files are never sorted (ListView1.Group(1)).

10-21-2006, 03:43 PM

IUnknown

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If you implement IComparer, you can sort the data in the list pretty much anyway you choose as you control what value the Compare method will return. If you want to sort within each group, you would probably need to compare both the grouping and the columns. There is an example in the MSDN2 on sorting listview groups, look for ListViewGroup Class.

Hope this helps!

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10-22-2006, 04:58 AM

ShadowWolf ShadowWolf is offline

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Solution

I read that article on MSDN2 and weren't able to get it to do anything but remove all my groups and sort folders and files mixed up in alphabetical order. However, during the night I got this idea, which is alot more simple and flexible than what M$ seems to have to offer. This is approximately what I did:

Code:

Dim DirInfo As New DirectoryInfo(Folder)
Dim Dirs() As DirectoryInfo = DirInfo.GetDirectories()
Dim Files() As FileInfo = DirInfo.GetFiles(Filter)

Array.Sort(Dirs, New DiretoryInfoComparer) 'Custom made comparer
Array.Sort(Files, New FileInfoComparer) 'Custom made comparer

For Each D As DirectoryInfo In Dirs 'Do this for the files too
'Add them to a listview with no sorting turned on
Next

One of the comparers look like this: (Still a WIP, I will add support for sorting different columns and in different orders etc.)

Code:

    Private Class DirectoryInfoComparer
        Implements IComparer

        Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
            Dim result As Int32 = String.Compare(CType(x, DirectoryInfo).Name, CType(y, DirectoryInfo).Name)

            Return result
        End Function
    End Class

Thanks for the help IUnknown, source for some of the ideas above were from the links you gave me. I hope the code above can help other people with the same problems.