Programming Microsoft Visual Basic .NET/Programming Microsoft Visual Basic .NET (Microsoft Press)(X08-78517)(2002).bin/setup/vbnet/17 controls/controlsdemo/listviewform.vb

Text File | 2002-03-16 | 11.5 KB | 300 lines

Imports System.IO

Public Class ListViewForm
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Friend WithEvents ListView1 As System.Windows.Forms.ListView
        Friend WithEvents ColumnHeader1 As System.Windows.Forms.ColumnHeader
    Friend WithEvents ColumnHeader2 As System.Windows.Forms.ColumnHeader
    Friend WithEvents ColumnHeader3 As System.Windows.Forms.ColumnHeader
    Friend WithEvents ColumnHeader4 As System.Windows.Forms.ColumnHeader
    Friend WithEvents ColumnHeader5 As System.Windows.Forms.ColumnHeader
    Friend WithEvents cboSort As System.Windows.Forms.ComboBox
    Friend WithEvents btnSort As System.Windows.Forms.Button
    Friend WithEvents btnList As System.Windows.Forms.Button
    Friend WithEvents btnShowChecked As System.Windows.Forms.Button

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.Container

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.
    'Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.btnSort = New System.Windows.Forms.Button()
        Me.ListView1 = New System.Windows.Forms.ListView()
        Me.ColumnHeader1 = New System.Windows.Forms.ColumnHeader()
        Me.ColumnHeader2 = New System.Windows.Forms.ColumnHeader()
        Me.ColumnHeader3 = New System.Windows.Forms.ColumnHeader()
        Me.ColumnHeader4 = New System.Windows.Forms.ColumnHeader()
        Me.ColumnHeader5 = New System.Windows.Forms.ColumnHeader()
        Me.cboSort = New System.Windows.Forms.ComboBox()
        Me.btnList = New System.Windows.Forms.Button()
        Me.btnShowChecked = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        '
        'btnSort
        '
        Me.btnSort.Location = New System.Drawing.Point(272, 16)
        Me.btnSort.Name = "btnSort"
        Me.btnSort.Size = New System.Drawing.Size(72, 26)
        Me.btnSort.TabIndex = 3
        Me.btnSort.Text = "Sort"
        '
        'ListView1
        '
        Me.ListView1.Anchor = (((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
                    Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right)
        Me.ListView1.CheckBoxes = True
        Me.ListView1.Columns.AddRange(New System.Windows.Forms.ColumnHeader() {Me.ColumnHeader1, Me.ColumnHeader2, Me.ColumnHeader3, Me.ColumnHeader4, Me.ColumnHeader5})
        Me.ListView1.Location = New System.Drawing.Point(8, 56)
        Me.ListView1.Name = "ListView1"
        Me.ListView1.Size = New System.Drawing.Size(664, 264)
        Me.ListView1.TabIndex = 0
        Me.ListView1.View = System.Windows.Forms.View.Details
        '
        'ColumnHeader1
        '
        Me.ColumnHeader1.Text = "Name"
        Me.ColumnHeader1.Width = 100
        '
        'ColumnHeader2
        '
        Me.ColumnHeader2.Text = "Size"
        Me.ColumnHeader2.Width = 75
        '
        'ColumnHeader3
        '
        Me.ColumnHeader3.Text = "Date Created"
        Me.ColumnHeader3.Width = 139
        '
        'ColumnHeader4
        '
        Me.ColumnHeader4.Text = "Date Modified"
        Me.ColumnHeader4.Width = 154
        '
        'ColumnHeader5
        '
        Me.ColumnHeader5.Text = "Last Access"
        Me.ColumnHeader5.Width = 177
        '
        'cboSort
        '
        Me.cboSort.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList
        Me.cboSort.DropDownWidth = 144
        Me.cboSort.Items.AddRange(New Object() {"Name", "Size", "Date Created", "Date Modified", "Date Accessed"})
        Me.cboSort.Location = New System.Drawing.Point(112, 16)
        Me.cboSort.Name = "cboSort"
        Me.cboSort.Size = New System.Drawing.Size(144, 26)
        Me.cboSort.TabIndex = 2
        '
        'btnList
        '
        Me.btnList.Location = New System.Drawing.Point(16, 16)
        Me.btnList.Name = "btnList"
        Me.btnList.Size = New System.Drawing.Size(72, 26)
        Me.btnList.TabIndex = 1
        Me.btnList.Text = "List files"
        '
        'btnShowChecked
        '
        Me.btnShowChecked.Location = New System.Drawing.Point(360, 16)
        Me.btnShowChecked.Name = "btnShowChecked"
        Me.btnShowChecked.Size = New System.Drawing.Size(120, 26)
        Me.btnShowChecked.TabIndex = 3
        Me.btnShowChecked.Text = "Show Checked"
        '
        'ListViewForm
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(7, 17)
        Me.ClientSize = New System.Drawing.Size(680, 325)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.btnShowChecked, Me.btnSort, Me.cboSort, Me.btnList, Me.ListView1})
        Me.Font = New System.Drawing.Font("Microsoft Sans Serif", 11.0!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Name = "ListViewForm"
        Me.Text = "ListView Demo"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub btnList_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnList.Click
        ' Get system directory
        Dim path As String = System.Environment.SystemDirectory
        ' show in caption
        Me.Text = "Files in " & path

        ' show file names in that directory, using alternating colors
        ShowFilesInListView(ListView1, System.Environment.SystemDirectory)
        PaintAlternatingBackColor(ListView1, Color.White, Color.Cyan)
        ' select the first one
        cboSort.SelectedIndex = 0
    End Sub

    ' A reusable routine that shows files in specified directory

    Sub ShowFilesInListView(ByVal lv As ListView, ByVal path As String)
        ' Get the DirectoryInfo object corresponding to the path
        Dim di As New DirectoryInfo(path)

        lv.BeginUpdate()
        lv.Items.Clear()

        ' Get data about all the files.
        Dim fi As FileInfo
        For Each fi In di.GetFiles()
            ' Add a new ListViewItem object, add to the Items collection
            Dim item As New ListViewItem(fi.Name)

            lv.Items.Add(item)

            item.SubItems.Add(fi.Length)
            item.SubItems.Add(fi.CreationTime)
            item.SubItems.Add(fi.LastWriteTime)
            item.SubItems.Add(fi.LastAccessTime)
        Next
        lv.EndUpdate()
    End Sub

    ' A reusable routine that displays alternating color for row background

    Sub PaintAlternatingBackColor(ByVal lv As ListView, ByVal color1 As Color, ByVal color2 As Color)
        Dim item As ListViewItem
        Dim subitem As ListViewItem.ListViewSubItem

        For Each item In lv.Items
            ' set the color for the Item.
            If (item.Index Mod 2) = 0 Then
                item.BackColor = color1
            Else
                item.BackColor = color2
            End If

            ' Assign same color to all subitems.
            For Each subitem In item.SubItems
                subitem.BackColor = item.BackColor
            Next
        Next
    End Sub

    ' sorts the elements of a the ListView

    Private Sub btnSort_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSort.Click

        ' Use the correct sort object.
        Dim index As Integer = cboSort.SelectedIndex
        Select Case index
            Case 0
                ' Sort by name.
                ListView1.ListViewItemSorter = New CompareByName()
            Case 1
                ' Sort by size.
                ListView1.ListViewItemSorter = New CompareBySize()
            Case 2, 3, 4
                ' Sort by one of the date properties.
                ListView1.ListViewItemSorter = New CompareByDate(index)
        End Select

        ' show we're busy doing the sort
        Cursor.Current = Cursors.WaitCursor

        ' Now we can sort the ListView.
        ListView1.Sort()
        PaintAlternatingBackColor(ListView1, Color.White, Color.Cyan)
        ' restore default cursor
        Cursor.Current = Cursors.Default
    End Sub

    ' an IComparer auxiliary class that helps to sort files by name

    Private Class CompareByName
        Implements IComparer

        Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
            ' cast the two arguments to ListViewItem objects
            Dim item1 As ListViewItem = DirectCast(x, ListViewItem)
            Dim item2 As ListViewItem = DirectCast(y, ListViewItem)
            ' compare their text property
            Return String.Compare(item1.Text, item2.Text)
        End Function
    End Class

    ' an IComparer auxiliary class that helps to sort files by their size

    Private Class CompareBySize
        Implements IComparer

        Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
            ' cast the two arguments to ListViewItem objects
            Dim item1 As ListViewItem = DirectCast(x, ListViewItem)
            Dim item2 As ListViewItem = DirectCast(y, ListViewItem)
            ' compare their 2nd subitem (the size)
            Return Math.Sign(CLng(item1.SubItems(1).Text) - CLng(item2.SubItems(1).Text))
        End Function
    End Class

    ' We can use one class for all date comparisons,
    ' just by passing a different subitem index.

    Private Class CompareByDate
        Implements IComparer

        Dim Index As Integer

        ' items in the ListView will be sorted on the date column whose
        ' index is passed to this constructor

        Sub New(ByVal subitemIndex As Integer)
            Me.Index = subitemIndex
        End Sub

        Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
            ' cast the two arguments to ListViewItem objects
            Dim item1 As ListViewItem = DirectCast(x, ListViewItem)
            Dim item2 As ListViewItem = DirectCast(y, ListViewItem)
            ' compare items on the specified datetime subitem
            Return Date.Compare(Date.Parse(item1.SubItems(Index).Text), Date.Parse(item2.SubItems(Index).Text))
        End Function
    End Class

    ' Display a list of all checked (selected) ListView items

    Private Sub btnShowChecked_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnShowChecked.Click
        Dim msg As String = ""
        Dim item As ListViewItem

        For Each item In ListView1.CheckedItems
            msg &= item.Text & ControlChars.CrLf
        Next

        If msg.Length = 0 Then
            msg = "No items have been checked"
        Else
            msg = "List of checked items" & ControlChars.CrLf & ControlChars.CrLf & msg
        End If
        MessageBox.Show(msg, "CheckedItems collection")
    End Sub
End Class