Need some list view help.. Please :) -> Resolved

[kleinma]

I might as well post my ListView class I wrote.

Its far from done, but it does the things I need it to do at the moment that the regular listview doesn't do.

These include
- Column Sorting on text, date, or numeric values
- added a Scroll event that fires when you scroll the listview (why did they leave that out?)
- Added a ColumnsResized event that will fire if you resize a column (good if you have custom controls like a textbox in the listview...)

I wrote a lot of this when i was less familiar with .net, so if anyone wants to make any suggestions please do. It does work fine though.

Option Strict On
Option Explicit On 
 
Imports System.Windows.Forms
Public Class ListViewScroll
    Inherits System.Windows.Forms.ListView
 
    'SCROLL CONSTANTS
    Private Const SBM_SETSCROLLINFO As Integer = &HE9
    Private Const WM_HSCROLL As Integer = &H115
    Private Const WM_VSCROLL As Integer = &H114
    'COLUMN RESIZE CONSTANTS
    Private Const WM_COLUMNRESIZE As Integer = 78
 
 
    'EVENTS
    Public Event Scroll(ByVal sender As Object, ByVal e As EventArgs)
    Public Event ColumnsResized(ByVal sender As Object)
 
    'PRIVATE VARS
    Private mSortOrder As SortOrder = SortOrder.None
    Private mSortColumnIndex As Integer = 0
    Private mAllowSort As Boolean = True
 
 
    Protected Sub OnScroll()
 
        RaiseEvent Scroll(Me, EventArgs.Empty)
 
    End Sub
 
    Protected Overridable Sub OnColumnHeaderResized()
        RaiseEvent ColumnsResized(Me)
    End Sub
    Protected Overrides Sub WndProc(ByRef m As System.windows.Forms.Message)
 
        MyBase.WndProc(m)
        If m.Msg = WM_HSCROLL Or m.Msg = WM_VSCROLL Or m.Msg = SBM_SETSCROLLINFO Then
 
            OnScroll()
 
        ElseIf m.Msg = WM_COLUMNRESIZE Then
 
            OnColumnHeaderResized()
 
        End If
 
    End Sub
 
 
    Public Property AllowColumnSorting() As Boolean
        Get
            Return mAllowSort
        End Get
        Set(ByVal Value As Boolean)
            mAllowSort = Value
        End Set
    End Property
    Protected Overrides Sub OnColumnClick(ByVal e As System.Windows.Forms.ColumnClickEventArgs)
        If Me.Items.Count = 0 Then Exit Sub
        If Not mAllowSort Then Exit Sub
 
        If e.Column = mSortColumnIndex Then
            Select Case Me.Sorting
                Case SortOrder.None, SortOrder.Descending
                    Me.Sorting = SortOrder.Ascending
                Case Else
                    Me.Sorting = SortOrder.Descending
            End Select
        Else
            Me.Sorting = SortOrder.Ascending
        End If
 
        mSortColumnIndex = e.Column
 
        Dim Sorter As ListViewSorter
 
        Select Case GetColumnType(e.Column)
            Case "DATE"
                Sorter = New ListViewSorter(e.Column, "DATE", Me.Sorting)
            Case "NUMBER"
                Sorter = New ListViewSorter(e.Column, "NUMBER", Me.Sorting)
            Case Else
                Sorter = New ListViewSorter(e.Column, "TEXT", Me.Sorting)
        End Select
 
        Me.ListViewItemSorter = Sorter
    End Sub
 
    Private Function GetColumnType(ByVal i As Integer) As String
        Try
            Date.Parse(Me.Items(0).SubItems(i).Text)
            Return "DATE"
        Catch ex As FormatException
            Try
                Double.Parse(Me.Items(0).SubItems(i).Text)
                Return "NUMBER"
            Catch exc As FormatException
                Return "TEXT"
            End Try
        End Try
    End Function
    Private Class ListViewSorter : Implements System.Collections.IComparer
 
        Public SortIndex As Integer
        Private mSortString As String
        Private mSortOrder As SortOrder
 
        Public Sub New(ByVal SortIndex As Integer, ByVal DataType As String, ByVal MySortOrder As SortOrder)
 
            Me.SortIndex = SortIndex
            mSortString = DataType
            mSortOrder = MySortOrder
        End Sub
 
        Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
 
 
            Dim LVI1 As ListViewItem
            Dim LVI2 As ListViewItem
 
            LVI1 = CType(x, ListViewItem)
            LVI2 = CType(y, ListViewItem)
 
            Select Case mSortString
                Case "DATE"
                    If mSortOrder = SortOrder.Ascending Then
                        Return Date.Compare(Date.Parse(LVI1.SubItems(SortIndex).Text), Date.Parse(LVI2.SubItems(SortIndex).Text))
                    Else
                        Return (Date.Compare(Date.Parse(LVI1.SubItems(SortIndex).Text), Date.Parse(LVI2.SubItems(SortIndex).Text)) * -1)
                    End If
                Case "NUMBER"
                    Dim N1 As Double = Double.Parse(LVI1.SubItems(SortIndex).Text)
                    Dim N2 As Double = Double.Parse(LVI2.SubItems(SortIndex).Text)
                    If mSortOrder = SortOrder.Ascending Then
                        Return N1.CompareTo(N2)
                    Else
                        Return (N1.CompareTo(N2) * -1)
                    End If
                Case Else
                    If mSortOrder = SortOrder.Ascending Then
                        Return String.Compare(LVI1.SubItems(SortIndex).Text, LVI2.SubItems(SortIndex).Text)
                    Else
                        Return (String.Compare(LVI1.SubItems(SortIndex).Text, LVI2.SubItems(SortIndex).Text) * -1)
                    End If
            End Select
 
        End Function
 
    End Class
End Class