TreeView BUG! Why?!

[behzad]

Hello All
I have a ListView with MultiSelect=False.
I found that SelectedIndexChanged event for ListViews raised twice for each selection except firs selection.
Firs for unselecting the selected item and Second for selecting the new item. So I should put the folowing code in SelectedIndexChanged event to prevent some excpetions when there is no item selected:

If ListView1.SelectedItems.Count = 0 Then Exit Sub

Next , I have 3 items in my listview and i want to change the selection to "Item 3" when "Item 1" have selected.So I have putted the following codes in SelectedIndexChanged event:

        MsgBox(ListView1.SelectedItems(0).Text)
        If ListView1.SelectedItems(0).Index = 0 Then
            ListView1.Items(2).Selected = True
        End If

As you see, I have added a message box that shows the selected item text.
Now, What is the BUG?
When I select "Item 1" (index=0) , it should show "Item 1" , then select "Item 3" (index=2) and show "Item 3", But this will occur twice ?! ( 4 MessageBox ) ! Why?

This is the complete code :

Public Class frmListViewTest
    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

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

    '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.
    Friend WithEvents ListView1 As System.Windows.Forms.ListView
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Dim ListViewItem1 As System.Windows.Forms.ListViewItem = New System.Windows.Forms.ListViewItem("Item 1")
        Dim ListViewItem2 As System.Windows.Forms.ListViewItem = New System.Windows.Forms.ListViewItem("Item 2")
        Dim ListViewItem3 As System.Windows.Forms.ListViewItem = New System.Windows.Forms.ListViewItem("Item 3")
        Me.ListView1 = New System.Windows.Forms.ListView
        Me.SuspendLayout()
        '
        'ListView1
        '
        Me.ListView1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.ListView1.Items.AddRange(New System.Windows.Forms.ListViewItem() {ListViewItem1, ListViewItem2, ListViewItem3})
        Me.ListView1.Location = New System.Drawing.Point(0, 0)
        Me.ListView1.MultiSelect = False
        Me.ListView1.Name = "ListView1"
        Me.ListView1.Size = New System.Drawing.Size(292, 266)
        Me.ListView1.TabIndex = 0
        Me.ListView1.View = System.Windows.Forms.View.List
        '
        'frmListViewTest
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Controls.Add(Me.ListView1)
        Me.Name = "frmListViewTest"
        Me.Text = "frmListViewTest"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub ListView1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListView1.SelectedIndexChanged
        If ListView1.SelectedItems.Count = 0 Then Exit Sub
        MsgBox(ListView1.SelectedItems(0).Text)
        If ListView1.SelectedItems(0).Index = 0 Then
            ListView1.Items(2).Selected = True
        End If
    End Sub
End Class

[behzad]

why ?????

[fret]

the SelectedIndexChange always trigger everytime you select the items in the listview that's why i think it appear many times in your messagebox. Maybe you can do a different twist like this one:

Private Sub ListView1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListView1.MouseDown
        Dim li As ListViewItem = ListView1.GetItemAt(e.X, e.Y)
        If li.SubItems(0).Text = "Item 1" Then
            li = ListView1.Items(li.Index + 2)
            li.Selected = True
        End If
        MessageBox.Show(li.SubItems(0).Text)
    End Sub

EDIT: BTW your topic is not a treeview its a listview

[kleinma]

you are creating a recursive loop because when you call the line

ListView1.Items(2).Selected = True

you then fire the selectedindex change event again... and it shows that message box before it comes back and finishes the first full run through the subroutine... set a break point on the line

Private Sub ListView1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListView1.SelectedIndexChanged

and run the code and step through line by line and you will see what is happening