问个 Treeview 背景色的有关问题

问个 Treeview 背景色的问题，
我用下面的代码设置 TreeView 的背景色，但出现一片白色空白，

VB code

    Dim lngStyle As Long    lngStyle = GetWindowLong(tvwRptList.hWnd, GWL_STYLE)    Call SetWindowLong(tvwRptList.hWnd, GWL_STYLE, lngStyle - TVS_HASLINES)    Call SetWindowLong(tvwRptList.hWnd, GWL_STYLE, lngStyle)    '½Úµã    Dim i As Long    For i = 1 To tvwRptList.Nodes.count        tvwRptList.Nodes(i).BackColor = mTreeBackColor 'RGB(255, 0, 0) 'mTreeBackColor        tvwRptList.Nodes(i).EnsureVisible    Next i        Call SendMessage(tvwRptList.hWnd, TVM_SETBKCOLOR, 0, ByVal mTreeBackColor)