Scroll Treeview Ketika Sedang Drag And Drop Sebuah Node

Option Explicit

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

Dim mfX As Single
Dim mfY As Single
Dim moNode As node
Dim m_iScrollDir As Integer
Dim mbFlag As Boolean

Private Sub Form_DragOver(Source As Control, x As Single, y As Single, State As Integer)
    If Source.Name = "TreeView1" Then
        Timer1.Enabled = False
    End If
End Sub

Private Sub Form_Load()
    Dim i As Integer
    Dim n As Integer
    Timer1.Enabled = False
    Timer1.Interval = 200
    TreeView1.Style = tvwTreelinesPlusMinusPictureText
    TreeView1.ImageList = ImageList1
    For i = 1 To 50
        TreeView1.Nodes.Add Text:="Node " & i, Image:=1, SelectedImage:=2
    Next i
    For i = 1 To 50
        For n = 1 To 5
            TreeView1.Nodes.Add Relative:=i, Relationship:=tvwChild, Text:="Child Node " & n, Image:=1, SelectedImage:=2
        Next n
    Next i
End Sub

Private Sub Timer1_Timer()
    Set TreeView1.DropHighlight = TreeView1.HitTest(mfX, mfY)
    If m_iScrollDir = -1 Then
        SendMessage TreeView1.hwnd, 277&, 0&, vbNull
    Else
        SendMessage TreeView1.hwnd, 277&, 1&, vbNull
    End If
End Sub

Private Sub TreeView1_DragDrop(Source As Control, x As Single, y As Single)
    If Not TreeView1.DropHighlight Is Nothing Then
        MsgBox moNode.Text & " was dropped on " & TreeView1.DropHighlight.Text
    End If
    Set TreeView1.DropHighlight = Nothing
    Set moNode = Nothing
    Timer1.Enabled = False
End Sub

Private Sub TreeView1_DragOver(Source As Control, x As Single, y As Single, State As Integer)
    Set TreeView1.DropHighlight = TreeView1.HitTest(x, y)
    mfX = x
    mfY = y
    If y > 0 And y < 100 Then
        m_iScrollDir = -1
        Timer1.Enabled = True
    ElseIf y > (TreeView1.Height - 200) And y < TreeView1.Height Then
        m_iScrollDir = 1
        Timer1.Enabled = True
    Else
        Timer1.Enabled = False
    End If
End Sub

Private Sub TreeView1_MouseUp(Button As Integer, Shift As Integer, x As Single, y As Single)
    Timer1.Enabled = False
End Sub

Private Sub TreeView1_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
    TreeView1.DropHighlight = TreeView1.HitTest(x, y)
    If Not TreeView1.DropHighlight Is Nothing Then
        TreeView1.SelectedItem = TreeView1.HitTest(x, y)
        Set moNode = TreeView1.SelectedItem
    End If
    Set TreeView1.DropHighlight = Nothing
End Sub

Private Sub TreeView1_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
    If Button = vbLeftButton Then
        TreeView1.DragIcon = TreeView1.SelectedItem.CreateDragImage
        TreeView1.Drag vbBeginDrag
    End If
End Sub