ListView (lsv)

ListView (lsv) - Allows the user to select a single (or multiple) items from a list with multiple columns.

You can add new items to a listview by adding ListViewItem objects to the Items collection.

Examples

Properties

Methods

Known Bugs

ListView.HideSelection = False

Visual Studio 2002
When this property equals False any manual changes to the backcolor of a listview are ignored.

The constructor for a ListViewItem can take a string (the caption for the icon) and an optional integer used as an index for the companion ListImage control.

Adding another item to an existing list

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = New System.Windows.Forms.ListViewItem("some text", 0) 
ListView1.Items.Add objListViewItem 

Or Alternatively

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = New System.Windows.Forms.ListViewItem() 
objListViewItem.Text = "some text" 
objListViewItem.ImageIndex = 0 
ListView1.Items.Add objListViewItem 

Inserting a new item at the beginning of the collection

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = New System.Windows.Forms.ListViewItem("Another item", 0) 
ListView1.Items.Insert(0, objListViewItem) 

The Bounds property returns a Rectangle object that tells where the item is on the screen

Individual subitems have there own Text, Font, ForeColor and BackColor properties

Dim objFont As System.Drawing.Font 
objFont = New System.Drawing.Font 

With objListViewItem.SubItems.Add("fourth column") 
   .Font = New System.Drawing.Font. 
   .ForeColor = System.Drawing.Color.Red 
   .BackColor = System.Drawing.Color.Yellow 
End With 

What is a ListViewItem ?

This is the object that represents an item in a ListView control
The ListViewItem class defines the appearance, behavior, and data associated with an item that is displayed in the ListView control.

The ListViewItem constructor can take a string and an optional integer used as an index for the accompanying image.

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = New System.Windows.Forms.ListViewItem("Item 1", 2). 
Me.ListView.Items.Add(objListViewItem) 

The properties window lets you add new ListViewItem objects and one or more subitems as well as all the ColumnHeader objects that you want to define

Properties

Methods

What is a ColumnHeader ?

This is the object that represents a single column header in a Listview control.
A column header is an item in a ListView control that contains heading text.
ColumnHeader objects can be added to a ListView using the Add method of the ListView.ColumnHeaderCollection class.
To add a group of columns to a ListView, you can use the AddRange method of the ListView.ColumnHeaderCollection class.
You can use the Index property of the ColumnHeader class to determine where the ColumnHeader is located in the ListView.ColumnHeaderCollection.

Dim objColumnHeader As System.Windows.Forms.ColumnHeader 
objColumnHeader = New System.Windows.Forms.ColumnHeader 
objColumnHeader.Text = "Article Title" 
'minus 20 to remove the horizontal scrollbar
objColumnHeader.Width = Me.ListView1.Width - 20 
Me.ListView1.Columns.Add(objColumnHeader) 

You can also resize the column widths at design time.

Properties

Methods

Events

SelectedIndexChanged

Private Sub lsvListView_SelectedIndexChanged(ByVal sender As System.Object, _ 
                                                   ByVal e As System.EventArgs) _ 
                                                   Handles lsvEmailHistoryListWide.SelectedIndexChanged 

'this is needed when the "MultiSelect" property = False
   If lsvListView.SelectedItems.Count = 0 Then Exit Sub 

End Sub 

Adding Items

You must make sure the View property has been changed to Details otherwise the subitems will not appear.
Subitems are only visible in Details view and only if you have defined a sufficient number of ColumnHeader objects.
You can create subitems by using the Add method of the ListViewItem's SubItems collection
You must add the listviewitem first before any subitems can be added.

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = New System.Windows.Forms.ListViewItem("Item 1"). 

Me.ListView.Items.Add(objListViewItem) 

objListViewItem.SubItems.Add("Sub Item 1") 
objListViewItem.SubItems.Add("Sub Item 2") 
objListViewItem.SubItems.Add("Sub Item 3") 

Inserting Items

It is also possible to insert items in a particular position

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = Me.ListView.Items.Insert(0, "some text") 

Retrieving SubItems

objListViewItem.SubItems(0).Text = "entry in the first column 
objListViewItem.SubItems(1).Text = "entry in the second column 

Removing individual items

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = New System.Windows.Forms.ListViewItem("Item 1"). 

Me.ListView.Items.Remove(objListViewItem) 
Me.ListView.Items.Remove(1) 

Removing all Items

ListView.Items.Clear 
ListView.ListViewItemCollection.Clear 

Removing all Column Headers

ListView.Columns.Clear 
ListView.ColumnHeaderCollection.Clear 

Removing both Items and Column Headers

ListView.Clear 

Single Selection

There is no SelectedIndex property of a listview but you can use the Selected property from a ListViewItem
The following selects the first item in the listview.

Me.ListView.Items(0).Selected = True 

Why is the Item not selected ?

Make sure that the listview has focus before you set the Selected property.

Multiple Selection

You can use the SelectedItems collection

The SelectedItems and SelectedIndices collections return the list of selected items

Editing Items

objListViewItem.Text = objListViewItem.SubItems(0).Text 

Dim objListViewItem As System.Windows.Forms.ListViewItem 

objListViewItem = Me.ListView.Items.Add("some text"). 

'The first item in the listview is SubItem 0.
objListViewItem.SubItems(1).Text = "10" 
objListViewItem.SubItems(2).Text = "20" 

Formatting SubItems

Individual subitems can have their own Text, Font, ForeColor and BackColor

Dim objListViewItem As System.Windows.Forms.ListViewItem 
objListViewItem = Me.ListView.Items.Add("some text"). 

With objListViewItem.SubItems.Add("some text") 
   .Text = 
  .Font = 
   .ForeColor = 
   .BackColor = 
End With 

Dragging Between Lists

Another common scenario where drag and drop is expected (and highly appreciated) involves moving items from one list of items to another. Typically buttons are also available in this scenario, but they require two mouse clicks (select the item, click the button). Drag and drop is more efficient here, because it only requires a single motion (select and drag).
The ListBox control does not support dragging multiple items. Clicking the list invalidates the multiple selection.

To move multiple items back and forth between two lists

Add two ListView controls to a form.
Set the AllowDrop property of each ListView control to true.
Set the MultiSelect property of each ListView control to true.
Set the View property of each ListView control to List.

Private Sub ListView_ItemDrag(ByVal sender As Object, _ 
                              ByVal e As System.Windows.Forms.ItemDragEventArgs) , _ 
                              Handles ListView1.ItemDrag, ListView2.ItemDrag 

    Dim myItem As ListViewItem 
    Dim myItems(sender.SelectedItems.Count - 1) As ListViewItem 
    Dim i As Integer = 0 

     ' Loop though the SelectedItems collection for the source.
    For Each myItem In sender.SelectedItems 
        ' Add the ListViewItem to the array of ListViewItems.
        myItems(i) = myItem 
        i = i + 1 
    Next 
    ' Create a DataObject containg the array of ListViewItems.
    sender.DoDragDrop(New DataObject("System.Windows.Forms.ListViewItem()", myItems), DragDropEffects.Move) 
    
End Sub 

The ListView and TreeView controls have an ItemDrag event that facilitates dragging.
A single ItemDrag event handler covers both controls; they are listed in the Handles clause. The sender parameter represents whichever control is initiating the drag.
The ItemDrag code creates an array of the type ListViewItem and populates it by looping through the SelectedItems collection.

Private Sub ListView_DragEnter(ByVal sender As Object, _ 
                               ByVal e As System.Windows.Forms.DragEventArgs) _ 
                               Handles ListView1.DragEnter, ListView2.DragEnter 

    ' Check for the custom DataFormat ListViewItem array.
    If e.Data.GetDataPresent("System.Windows.Forms.ListViewItem()") Then 
        e.Effect = DragDropEffects.Move 
    Else 
        e.Effect = DragDropEffects.None 
    End If 
End Sub 

Private Sub ListView_DragDrop(ByVal sender As Object, _ 
                              ByVal e As System.Windows.Forms.DragEventArgs) _ 
                              Handles ListView1.DragDrop, ListView2.DragDrop 

    Dim myItem As ListViewItem 
    Dim myItems() As ListViewItem = e.Data.GetData("System.Windows.Forms.ListViewItem()") 
    Dim i As Integer = 0 

    For Each myItem In myItems 
        ' Add the item to the target list.
        sender.Items.Add(myItems(i).Text) 
        ' Remove the item from the source list.
        If sender Is ListView1 Then 
            ListView2.Items.Remove(ListView2.SelectedItems.Item(0)) 
        Else 
            ListView1.Items.Remove(ListView1.SelectedItems.Item(0)) 
        End If 
        i = i + 1 
    Next 
End Sub 

Because the DataFormats class does not include a member of type ListViewItem, the data must be passed as a system Type instead. In the DoDragDrop method, a new DataObject is created and populated with the array. This same technique can be used to drag and drop any system Type.

In the DragDrop event, the array is copied from the DataObject into a new ListViewItem array, and each ListViewItem is added to the Items collection of the target ListView control.

Sorting

ListViewItemSorter Property

You can use this property to provide custom sorting, for example, when a column header is clicked in the details view.
First create a class that implements the IComparer interface and provides a constructor that accepts the index of a column to sort by.
This sorting will then be performed when you call the Sort method or when items are added to the list.
When you set the ListViewItemSorter property to the new instance, the ListView control is automatically sorted using the specified object.
Subsequent calls to the Sort method use the same object.
Note that items are not sorted automatically when their label text changes.

Add a ColumnClick Event Handler

Include the total number of columns and how you want each one to be sorted.

Private Sub lsvListView_ColumnClick 
   Private Sub lsvDatabase_ColumnClick(ByVal sender As Object, _ 
                                       ByVal e As System.Windows.Forms.ColumnClickEventArgs) _ 
                                       Handles lsvDatabase.ColumnClick 

         Select Case e.Column 
            Case 0 : Call clsListView.ColumnSort(lsvListView, "Number", e.Column) 
            Case 1 : Call clsListView.ColumnSort(lsvListView, "String", e.Column) 
            Case 2 : Call clsListView.ColumnSort(lsvListView, "String", e.Column) 
            Case 3 : Call clsListView.ColumnSort(lsvListView, "Number", e.Column) 
         End Select 

   End Sub 

ImageLists

LargeImageList - used for the images in Large Icon view
SmallImageList - used for the images in Small Icon, List and Details view

Files in a Folder

Public Shared FolderToListView(sFolderPath As String) 
   Dim objdirectoryinfo As System.IO.DirectoryInfo 
   Dim objfileinfo As System.IO.FileInfo 
   Dim objlistviewitem As System.Windows.Forms.ListViewItem 

   objdirectoryinfo = New System.IO.DirectoryInfo(sFolderPath) 

   Me.ListView.BeginUpdate 
   For Each objfileinfo In objdirectoryinfo.GetFiles() 

   objlistviewitem = Me.ListView.Items.Add(objfileinfo.Name). 

   objlistviewitem.SubItems.Add(objfileinfo.Length) 
   objlistviewitem.SubItems.Add(objfileinfo.CreationTime) 
   objlistviewitem.SubItems.Add(objfileinfo.LastWriteTime) 
   objlistviewitem.SubItems.Add(objfileinfo.LastAccessTime) 

   Next objfileinfo 

   Me.ListView.EndUpdate 
End Sub