[2005] Sort, recolumn, etc in Listview

[mulhearn22]

Hi,

I'm making an audio player and want to implement the common listview that applications like iTunes, SongBird, etc implement. They all have the column titles, which you can drag and rearrange, sort by column, add/remove columns, etc. Anyone have a tutorial I can look at or somewhere I can start? I'm thinking I have to make my own control with the ListView as my base but I'm not sure. All help will be welcome.

TIA,
Matt

[.paul.]

what information will you have in your columns?
do you want to be able to sort on any column?

you can set .allowcolumnreorder so you can reorder your columns, but if you are planning on having multiple sorting columns, remember you'll need to keep track of the columns by title instead of by index number.

[mulhearn22]

Yes, I would want to allow sorting by any column, which in of itself would be dynamic. It's a music player, so like iTunes, I want to be able to do allow the user to right click the column headers, select what columns to display, and sort by them. I did find that property that allowed for reordering which is great, but I'm still stuck on the others.

Also, my listview is only allowing me to select the first column and now the whole row when I select a row. To clarify, when you select a row, the row's bgcolor changes. The bgcolor only changes for the first column. Though the program understands that the whole row is selected, the visual effect isn't what I'm looking for. Any ideas on that?

[Negative0]

To fix your first column selection issue, set the FullRowSelect property to True.

[mulhearn22]

Excellent Negative0. I was looking for that property but I thought it would be something like "SelectEntireRow" or something. Of course they would start it with 'F'....

Anyone have ideas about my other issue?

[.paul.]

if the information in your columns is all strings, its easy.
if you have different datatypes in your columns (strings, numbers, dates) you need to know which column has been clicked + sort it by the appropriate datatype. heres a sorter i use for a listview withe strings, currency, + dates:

Public Class clsListViewItemComparer
    Implements IComparer
 
    Private _Column As Integer
    Private _Numeric As Boolean = False
    Private _isDate As Boolean = False
    Private _sortAscending As Boolean = False
 
    Public Property Column() As Integer
        Get
            Return _Column
        End Get
        Set(ByVal Value As Integer)
            _Column = Value
        End Set
    End Property
 
    Public Property Numeric() As Boolean
        Get
            Return _Numeric
        End Get
        Set(ByVal Value As Boolean)
            _Numeric = Value
        End Set
    End Property
 
    Public Property isDate() As Boolean
        Get
            Return _isDate
        End Get
        Set(ByVal Value As Boolean)
            _isDate = Value
        End Set
    End Property
 
    Public Property sortAscending() As Boolean
        Get
            Return _sortAscending
        End Get
        Set(ByVal Value As Boolean)
            _sortAscending = Value
        End Set
    End Property
 
    Public Sub New(ByVal columnIndex As Integer)
        Column = columnIndex
    End Sub
 
    Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
        Dim ListX As ListViewItem = CType(x, ListViewItem)
        Dim ListY As ListViewItem = CType(y, ListViewItem)
 
        If Numeric Then
            ' Convert column text to numbers before comparing.
            ' If the conversion fails, just use the value 0.
            Dim ListXVal, ListYVal As Decimal
            Try
                ListXVal = Decimal.Parse(Replace(ListX.SubItems(Column).Text, "£", ""))
            Catch
                ListXVal = 0
            End Try
 
            Try
                ListYVal = Decimal.Parse(Replace(ListY.SubItems(Column).Text, "£", ""))
            Catch
                ListYVal = 0
            End Try
 
            If Not sortAscending Then
                Return Decimal.Compare(ListYVal, ListXVal)
            Else
                Return Decimal.Compare(ListXVal, ListYVal)
            End If
 
        ElseIf isDate Then
            Dim ListXVal, ListYVal As Date
            Try
                ListXVal = Date.Parse(ListX.SubItems(Column).Text)
            Catch
                'ListXVal = 0
            End Try
 
            Try
                ListYVal = Date.Parse(ListY.SubItems(Column).Text)
            Catch
                'ListYVal = 0
            End Try
 
            If Not sortAscending Then
                Return Date.Compare(ListYVal, ListXVal)
            Else
                Return Date.Compare(ListXVal, ListYVal)
            End If
 
        Else
            ' Keep the column text in its native string format
            ' and perform an alphabetic comparison.
            Dim ListXText As String = ListX.SubItems(Column).Text
            Dim ListYText As String = ListY.SubItems(Column).Text
 
            If Not sortAscending Then
                Return String.Compare(ListYText, ListXText)
            Else
                Return String.Compare(ListXText, ListYText)
            End If
 
        End If
 
    End Function
End Class

[mulhearn22]

I'm sorry to make you walk me through this, but how would I go about implementing that (assuming I'm sorting strings)?

[mulhearn22]

hey, actually i got it. however, now i think i need to sort based on multiple columns (such as by artist, then by album, then by track number so that tracks stick together and are in order). any ideas on that one?

[.paul.]

can you post some example information? i'll put it in a listview + try to write a custom sorter. its not difficult but its always easier when you've got something to test it with.

[mulhearn22]

im not exactly sure what to post. basically, i have a listview with artist, album, title, track num, year, genre. if you sort by say track num and then by artist, the tracks get out of order because i'm only sorting by artist, not artist, then album, then track. iTunes does this really well.

if this is unclear, let me know what code you're looking for and i'll post it. thanks for the help!