在通常情況下，treeview的背景色是不可以修改的，我們可以通過API實現，源碼如下

Option Explicit

Private Declare Function SendMessage Lib "User32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Long) As Long
Private Declare Function GetWindowLong Lib "User32" Alias "GetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "User32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Private Const GWL_STYLE = -16&
Private Const TVM_SETBKCOLOR = 4381&
Private Const TVM_GETBKCOLOR = 4383&
Private Const TVS_HASLINES = 2&

Private Sub Form_Load()

Dim nodex As Node
Dim i As Integer
Dim lStyle As Long

Call SendMessage(TreeView1.hWnd, TVM_SETBKCOLOR, 0, ByVal RGB(255, 0, 0))
lStyle = GetWindowLong(TreeView1.hWnd, GWL_STYLE)
Call SetWindowLong(TreeView1.hWnd, GWL_STYLE, lStyle - TVS_HASLINES)
Call SetWindowLong(TreeView1.hWnd, GWL_STYLE, lStyle)

TreeView1.Style = tvwTreelinesPlusMinusPictureText
TreeView1.BorderStyle = ccFixedSingle
With TreeView1.Nodes
Set nodex = .Add(, , "R", "Root")
nodex.BackColor = RGB(255, 0, 0)
For i = 1 To 10
Set nodex = .Add("R", tvwChild, "C" & i, "Child " & i)
nodex.BackColor = RGB(255, 0, 0)
nodex.EnsureVisible
Next
End With

End Sub