BCB中如何下载HTTP服务器文件实现软件更新

 /*Unit1.cpp*/

void __fastcall TForm1::Button1Click(TObject *Sender)
{
　stream = new TIdMultiPartFormDataStream();
　IdHTTP1 = new TIdHTTP(NULL);
　 try{
　　stream->AddFormField("FieldName","file"); //file与处理input名称一致
　　 stream->AddFile("FiledName","C:\\1.gif","multipart/form-data");
　　 stream->Position = 0;
　　pbS->Position = 0;
　　pbS->Max =  stream->Size;
　　IdAntiFreeze1->OnlyWhenIdle = false;
　　 Timer1->Enabled = true;
　　IdHTTP1->Request->ContentType = "multipart/form-data";
　　Edit1->Text = IdHTTP1->Post("http://127.0.0.1/scripts/index.jsp",stream);
　　Timer1->Enabled = false;
　}__finally{
　　stream->Free();
　　IdHTTP1->Free();
　}

}

//---------------------------------------
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
　　 pbS->Position = stream->Position;
　　Edit1->Text = IntToStr(pbS->Position)+"\/"+pbS->Max;
}