BeforeNavigate2内的代码如下。为什么网页从cache里面读取呢，必须手工刷新一下才读取正确的页面？

void __fastcall TFormBrowser::WebBrowserBeforeNavigate2(TObject *Sender,
LPDISPATCH pDisp, Variant *URL, Variant *Flags,
Variant *TargetFrameName, Variant *PostData, Variant *Headers,
VARIANT_BOOL *Cancel)
{
if (((String)*URL).Pos("client=G") < 1)
{//注入定制客户端标志
String Path = ((String)*URL);
if (Path.Pos("?") > 0)
Path += "&client=G";
else
Path += "?client=G";
*Cancel = (VARIANT_BOOL)true;
WebBrowser->Navigate(WideString(Path).c_bstr());
}
else
{
String FullPath = ((String)*URL);
long Pos = FullPath.Pos("//");
if (Pos > 0) FullPath = FullPath.SubString(Pos+2, FullPath.Length());
Pos = FullPath.Pos("/");
if (Pos <= 0)
FullPath = "/";
else
FullPath = FullPath.SubString(Pos, FullPath.Length());

*Cancel = (VARIANT_BOOL)LoadModules(FullPath.LowerCase());
}
}