终于在TreeView里加进了背景！！！

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
Graphics::TBitmap *bmp;
TWndMethod ms;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
bmp=new Graphics::TBitmap();
bmp->LoadFromFile("E:\\Gif\\071_03.BMP");
TV->Canvas->Brush->Bitmap=bmp;
ms=TV->WindowProc;
TV->WindowProc=proc;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::proc(TMessage &msg)
{
if(msg.Msg==WM_ERASEBKGND) return;
if(msg.Msg==WM_PAINT)
{
TRect ARect=TV->ClientRect;
int W=ARect.Width();
int H=ARect.Height();

HDC memdc=CreateCompatibleDC(TV->Canvas->Handle);
HBITMAP membmp=CreateCompatibleBitmap(TV->Canvas->Handle,W,H);
SelectObject(memdc,membmp);
ms(msg);
BitBlt(memdc,0,0,W,H,TV->Canvas->Handle,0,0,SRCCOPY);

HDC maskdc=CreateCompatibleDC(TV->Canvas->Handle);
HBITMAP maskbmp=CreateBitmap(W,H,1,1,NULL);
SelectObject(maskdc,maskbmp);
BitBlt(maskdc,0,0,W,H,memdc,0,0,SRCCOPY);

TV->Canvas->FillRect(ARect);

SetBkColor(memdc,RGB(0,0,0));
SetTextColor(memdc,RGB(255,255,255));
BitBlt(memdc,0,0,W,H,maskdc,0,0,SRCAND);

SetBkColor(TV->Canvas->Handle,RGB(255,255,255));
SetTextColor(TV->Canvas->Handle,RGB(0,0,0));

BitBlt(TV->Canvas->Handle,0,0,W,H,maskdc,0,0,SRCAND);
BitBlt(TV->Canvas->Handle,0,0,W,H,memdc,0,0,SRCPAINT);

DeleteObject(memdc);
DeleteObject(membmp);
DeleteObject(maskdc);
DeleteObject(maskbmp);
}
else
ms(msg);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormDestroy(TObject *Sender)
{
delete bmp;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::TVExpanded(TObject *Sender, TTreeNode *Node)
{
TV->Repaint();
}
//---------------------------------------------------------------------------