Binaryworld - CTreeViewEdit - A class for enhanced treeview node editing ... [ VB -> Controls-TreeView ]

'-------------------------------------------------------
' The CTREEVIEWEDIT Class module
'
' This class lets you use a regular TextBox control to
' edit a treeview node's label. All you have to do to
' use this class is adding a TextBox control to the same
' form that hosts the TreeView control, and initialize
' an instance of the class from inside the form's Load
' event. In the following example we have a treeview
' control named tvwHierarchy and a support textbox control
' named txtSupport

' Dim TVEdit As New CTreeViewEdit
'
' Private Sub Form_Load()
'   TVEdit.Init tvwHierarchy, txtSupport
' End Sub

' You can then write code in the event procs of txtSupport,
' as you would do with a regular textbox. For example you
' can filter out invalid keys. You can also terminate the
' edit mode by invoking the class's EndLabelEdit method
' (pass True to accept the new value, False to reject it)

'Private Sub txtSupport_KeyPress(KeyAscii As Integer)
'  If KeyAscii >= 48 And KeyAscii <= 57 Then
'    ' filter out numeric keys
'    KeyAscii = 0
'  ElseIf KeyAscii = 8 Then
'    ' the backspace cancels the operation
'    TVEdit.EndLabelEdit False
'  End If
'End Sub
'-------------------------------------------------------

'-------------------------------------------------------
' API Declares
'-------------------------------------------------------
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal _
  hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _
  lParam As Any) As Long
Private Declare Function GetClientRect Lib "user32" (ByVal hWnd As Long, _
  lpRect As RECT) As Long
Private Declare Function SetCapture Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function ReleaseCapture Lib "user32" () As Long

Private Type RECT
  Left As Long
  Top As Long
  Right As Long
  Bottom As Long
End Type

Private Const TV_FIRST = &H1100
Private Const TVM_GETITEMRECT = (TV_FIRST + 4)
Private Const TVM_GETNEXTITEM = (TV_FIRST + 10)
Private Const TVGN_CARET = 9

'-------------------------------------------------------
' module variables
'-------------------------------------------------------

' the TreeView control
Dim WithEvents TreeView As TreeView
' the hidden textbox control
Dim WithEvents TextBox As TextBox
' the parent form (can be anything)
Dim Parent As Object

' these variables are active when the user is editing the node label
' the previous value of the Node's Text property
Dim saveText As String
' the control that had Default = True
Dim defaultCtrl As Object
' the control that had Cancel = True
Dim cancelCtrl As Object

' Initialize this instance

Sub Init(TView As TreeView, TBox As TextBox)
  Set TreeView = TView
  Set TextBox = TBox
  Set Parent = TextBox.Parent
  TextBox.Visible = False
End Sub

'-------------------------------------------------------
' event procedures
'-------------------------------------------------------

' when the user clicks on a treeview's item
' this procedure gets the control and cancels
' the default operation

Private Sub TreeView_BeforeLabelEdit(Cancel As Integer)
  Cancel = True
  StartLabelEdit
End Sub

' when the user types in the textbox, grow or shrink it

Private Sub TextBox_Change()
  Dim saveFont As StdFont
  Dim wi As Single
  Dim borderWidth As Single

  ' temporarily change the parent form's font,
  ' to use its TextWidth method
  Set saveFont = Parent.Font
  Set Parent.Font = TextBox.Font
  wi = Parent.TextWidth(TextBox.Text) + Parent.ScaleX(20, vbPixels, _
    Parent.ScaleMode)
  Set Parent.Font = saveFont
  ' this is the Treeview's border, in the same coordinate
  ' system as the parent form
  borderWidth = Parent.ScaleX(2, vbPixels, Parent.ScaleMode)

  ' don't let the textbox grow larger than the treeview
  If TextBox.Left + wi > TreeView.Left + TreeView.Width - borderWidth Then
    wi = TreeView.Left + TreeView.Width - TextBox.Left - borderWidth
  End If

  TextBox.Width = wi

End Sub

' terminate the edit mode when the user types
' Enter or Escape keys

Private Sub TextBox_KeyPress(KeyAscii As Integer)
  Select Case KeyAscii
    Case 13
      EndLabelEdit True
      KeyAscii = 0
    Case 27
      EndLabelEdit False
      KeyAscii = 0
  End Select
End Sub

' terminate the edit mode when the user clicks
' outside of the textbox control

Private Sub TextBox_MouseDown(Button As Integer, Shift As Integer, X As Single, _
  Y As Single)
  If X < 0 Or Y < 0 Or X > TextBox.Width Or Y > TextBox.Height Then
    EndLabelEdit True
  End If
End Sub

'-------------------------------------------------------
' Support routines
'-------------------------------------------------------

' enter edit mode

Private Sub StartLabelEdit()
  ' get the edit rectangle for the selected item
  Dim lpRect As RECT, lpClientRect As RECT
  Dim hNode As Long

  ' get the handle of the selected node
  hNode = SendMessage(TreeView.hWnd, TVM_GETNEXTITEM, TVGN_CARET, ByVal 0&)
  ' get the bounding rectangle for this node
  ' the function expects in input the handle of the item
  ' at the beginning of the RECT structure
  lpRect.Left = hNode
  If SendMessage(TreeView.hWnd, TVM_GETITEMRECT, True, lpRect) = 0 Then
    ' a zero value means error
    Exit Sub
  End If

  ' convert coordinates into form coordinates
  With lpRect
    .Left = TreeView.Left + Parent.ScaleX(.Left, vbPixels, Parent.ScaleMode)
    .Top = TreeView.Top + Parent.ScaleY(.Top, vbPixels, Parent.ScaleMode)
    .Right = TreeView.Left + Parent.ScaleX(.Right, vbPixels, _
      Parent.ScaleMode)
    .Bottom = TreeView.Top + Parent.ScaleY(.Bottom, vbPixels, _
      Parent.ScaleMode)
  End With

  ' move the textbox in front of the TreeView
  With TextBox
    ' move the textbox in the right position
    .Move lpRect.Left, lpRect.Top, lpRect.Right - lpRect.Left + 200, _
      lpRect.Bottom - lpRect.Top
    .ZOrder

    ' transfer the node's text to the TextBox control
    .Text = TreeView.SelectedItem.Text
    .SelStart = 0
    .SelLength = Len(.Text)
    Set .Font = TreeView.Font

    ' make the textbox visible and give it the focus
    .Visible = True
    .SetFocus

    ' grab the mouse capture
    SetCapture .hWnd

    ' disable any button with Default or Cancel property
    ' this is necessary because we want to trap the Enter
    ' and Cancel keys while the user is editing the
    ' node's label.
    Set defaultCtrl = Nothing
    Set cancelCtrl = Nothing
    Dim ctrl As Control

    On Error Resume Next

    For Each ctrl In Parent.Controls
      If ctrl.Default = False Then
        ' not supported or Default = False
      Else
        Set defaultCtrl = ctrl
        ctrl.Default = False
      End If
      If ctrl.Cancel = False Then
        ' not supported or Cancel = False
      Else
        Set cancelCtrl = ctrl
        ctrl.Cancel = False
      End If
    Next

    ' save node's text, then clear it - this is necessary to avoid the
    ' original
    ' text appears if the editing textbox shrinks
    saveText = TreeView.SelectedItem.Text
    TreeView.SelectedItem.Text = ""

  End With

End Sub

' this procedure is called from TextBox event procs
' or by the client application

Sub EndLabelEdit(AcceptIt As Boolean)
  If