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  <b>bool</b> path_set;
  TNotifyEvent FOnChangeFile;&nbsp;&nbsp;&nbsp;&nbsp;<font color="#0000AA"><i>//Change event</i></font>
  TDirectoryThread *thrd;&nbsp;&nbsp;&nbsp;&nbsp;<font color="#0000AA"><i>//Monitoring thread</i></font>
  AnsiString FPath;
  <b>void</b> <b>__fastcall</b> SetPath(String path);
  <b>void</b> <b>__fastcall</b> PopulateFileList();
<b>protected</b>:
<b>public</b>:
  <b>__fastcall</b> TActiveListBox(TComponent* Owner);
  <b>__fastcall</b> ~TActiveListBox();
  <b>void</b> <b>__fastcall</b> UpdateNotify();
  <b>void</b> <b>__fastcall</b> Restart();
<b>__published</b>:
  <b>__property</b> AnsiString MonitorPath = {read=FPath,write=SetPath};
  <b>__property</b> TNotifyEvent OnDirectoryChange = {read=FOnChangeFile,write=FOnChangeFile};
};
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<font color="202020">#endif</font></pre> 
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<tr bgcolor=blue><td><font face="Arial" color=white>ActiveListBox.cpp</font></td></tr> 
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<pre>
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>

<font color="202020">#include &lt;vcl.h&gt;</font>
<font color="202020">#pragma hdrstop</font>

<font color="202020">#include &quot;ActiveListBox.h&quot;</font>
<font color="202020">#pragma package(smart_init)</font>
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<font color="#0000AA"><i>// ValidCtrCheck is used to assure that the components created do not have</i></font>
<font color="#0000AA"><i>// any pure virtual functions.</i></font>
<font color="#0000AA"><i>//</i></font>

static <b>inline</b> <b>void</b> ValidCtrCheck(TActiveListBox *)
{
  <b>new</b> TActiveListBox(NULL);
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>__fastcall</b> TActiveListBox::TActiveListBox(TComponent* Owner)
  : TListBox(Owner)
{
  path_set=<b>false</b>;                     <font color="#0000AA"><i>//boolean to check if path has been set</i></font>
  FPath=<font color="#0000FF">&quot;&quot;</font>;
  FOnChangeFile=NULL;
  thrd = <b>new</b> TDirectoryThread(<b>this</b>);  <font color="#0000AA"><i>//create thread</i></font>
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>__fastcall</b> TActiveListBox::~TActiveListBox()
{
  thrd-&gt;Terminate();
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TActiveListBox::SetPath(String path)
{
  FPath = path;
  PopulateFileList();
  thrd-&gt;SetMonitorPath(FPath);
  <b>if</b> (!path_set)                <font color="#0000AA"><i>//if the path hasn't been set yet...</i></font>
  {
    path_set=true;
    thrd-&gt;Resume();             <font color="#0000AA"><i>//start the thread</i></font>
  }
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TActiveListBox::UpdateNotify() <font color="#0000AA"><i>//notify the listbox of changes</i></font>
{
  PopulateFileList();
  <b>if</b> (FOnChangeFile)
    FOnChangeFile(<b>this</b>);
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TActiveListBox::PopulateFileList() <font color="#0000AA"><i>//fill list box w/ files</i></font>
{
  TSearchRec sr;
  Items-&gt;Clear();
  <b>if</b> (FPath == <font color="#0000FF">&quot;&quot;</font>) <b>return</b>;
  FindFirst(FPath+<font color="#0000FF">&quot;*.*&quot;</font>,faAnyFile,sr);
  <b>do</b> {
    Items-&gt;Add(sr.Name);
  } <b>while</b> (!FindNext(sr));
  FindClose(sr);
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TActiveListBox::Restart()
{
  path_set=<b>false</b>;
  thrd = <b>new</b> TDirectoryThread(<b>this</b>);
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>namespace</b> Activelistbox
{
  <b>void</b> <b>__fastcall</b> PACKAGE <b>Register</b>()
  {
     TComponentClass classes[1] = {<b>__classid</b>(TActiveListBox)};
     RegisterComponents(<font color="#0000FF">&quot;Samples&quot;</font>, classes, 0);
  }
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>__fastcall</b> TDirectoryThread::TDirectoryThread(TActiveListBox *ctrl)
  : TThread(true)
{
  control = ctrl;
  path = <font color="#0000FF">&quot;&quot;</font>;
  FreeOnTerminate = true;
  OnTerminate = ThreadFinish;
  hNotify = INVALID_HANDLE_VALUE;
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TDirectoryThread::Execute()
{
  <b>if</b> (path.IsEmpty() || (hNotify == INVALID_HANDLE_VALUE))
  {
    control-&gt;Restart();
    <b>throw</b> Exception(<font color="#0000FF">&quot;couldn't start&quot;</font>);
  }
  <b>bool</b> to=true;  <font color="#0000AA"><i>//time-out check</i></font>
  <font color="#0000AA"><i>//while we're still going...</i></font>
  <b>while</b> (!Terminated &amp;&amp; (hNotify != INVALID_HANDLE_VALUE))
  {
    <font color="#0000AA"><i>//while we're still timed out...</i></font>
    <b>while</b> (to &amp;&amp; !Suspended &amp;&amp; !Terminated)
    {
      <b>unsigned</b> <b>long</b> stat = WaitForSingleObject(hNotify,2000);
      <font color="#0000AA"><i>//our call to WaitForSingleObject has a 2 second timeout to avoid thread-lock</i></font>
      <b>if</b> (stat == WAIT_OBJECT_0) <font color="#0000AA"><i>//if it got signalled</i></font>
      {
        to=true;
        Synchronize(Update());  <font color="#0000AA"><i>//update list box</i></font>
        <font color="#0000AA"><i>//use Synchronize to keep it thread-safe</i></font>
        <b>if</b> (!FindNextChangeNotification(hNotify)) <font color="#0000AA"><i>//renew the handle</i></font>
        {
          to=<b>false</b>;
          <b>break</b>;
        }
      }
      <b>else</b> <b>if</b> (stat == WAIT_TIMEOUT)      <font color="#0000AA"><i>//just keep going</i></font>
        to=true;
      <b>else</b> {
        to=<b>false</b>;
        <b>break</b>;
      }
    }
  }
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TDirectoryThread::SetMonitorPath(String Path)
{
  <b>if</b> (path != Path)
  {
    path = Path;
    <b>if</b> (hNotify != INVALID_HANDLE_VALUE)    <font color="#0000AA"><i>//close our old handle</i></font>
      FindCloseChangeNotification(hNotify);

    hNotify = FindFirstChangeNotification(path.c_str(),<b>false</b>,dwFlags);
    <font color="#0000AA"><i>//get the handle to the event object</i></font>
    <b>if</b> (hNotify == INVALID_HANDLE_VALUE)
      <b>throw</b> Exception(<font color="#0000FF">&quot;couldn't make handle&quot;</font>);
  }
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TDirectoryThread::ThreadFinish(TObject *Sender)
{
  FindCloseChangeNotification(hNotify); <font color="#0000AA"><i>//cleanup</i></font>
}
<font color="#0000AA"><i>//---------------------------------------------------------------------------</i></font>
<b>void</b> <b>__fastcall</b> TDirectoryThread::Update()
{
  control-&gt;UpdateNotify();
}
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