C++ Builder中實現MAPX的Feature

昨天試了一天的Feature,現在還存在的問題有：
1)無法將CMapX***Disp 轉換成 tagVariant, 例如例子中，創建線及區域時， 無論你寫成下面的任何一種，都創建不成功， 
      Map1->Layers->_Item(Variant(1))->CreateRegion(points, EmptyParam);//編譯失敗
      Map1->Layers->_Item(Variant(1))->CreateRegion(Variant((IUnknown *)points), EmptyParam);//運行創建不成功      
應該寫爲：
    Map1->Layers->_Item(Variant(1))->CreateRegion(Variant((CMapXPoints*)points), EmptyParam);//運行創建不成功

而只好改用下面的兩行代碼：
      feature = Map1->FeatureFactory->CreateRegion(EmptyParam, EmptyParam);
      feature->Parts->Add(points);
2)下面的示例中保留了一個錯誤，就是用 下面的代碼創建Feature時，程序退出會拋出異常。現在還沒找到解決的方法，也只好改用其它的方法，如 CreateRegion中使用的方法    
        CMapXFeatureDisp line;
      line.Bind(StringToOleStr("MapX.Feature.5"));
      line.Attach(Map1->OleObject);
3)文本顯示不能顯示在層上(已解決)：.
將原來的Variant("文本圖元")改爲Variant(WideString("文本圖元"))就可以了，但如果有中文，則沒了後面的四個字節，只顯示“文本”。
示例代碼：
void __fastcall TfrmFeature::Map1MouseUp(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{ //只向 動畫層中加圖元
  if((Button != mbLeft) || (placeFeatureId == -1)) return;
  if(Map1->Layers->Count == 0 ){
    log("日誌", "沒有圖層或動畫圖層， 不能完成添加Feature的工作");
    placeFeatureId = -1;
    return;
  }
  //動作名稱
  String strFeature;
  CMapXPointDisp point;
  //生成的圖元
  CMapXFeature * feature = NULL;

  point.Bind(StringToOleStr("MapX.Point.5"));
  point = Map1->ConvertCoordP(Variant(X), Variant(Y), miScreenToMap);

  switch (placeFeatureId)
  {
    case 0:{
      CMapXPointDisp p1;
      CMapXPointDisp p2;
      p1.Bind(StringToOleStr("MapX.Point.5"));
      p2.Bind(StringToOleStr("MapX.Point.5"));
      p1.Set_(point.get_X() -1.0, point.get_Y() + 0.2);
      p2.Set_(point.get_X() + 0.4, point.get_Y() -0.4);
      feature = Map1->FeatureFactory->CreateArc(p1, p2, EmptyParam, EmptyParam, EmptyParam, EmptyParam);
      Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);
      strFeature = "形似弧的線圖元";}
      break;
    case 1:{
      feature = Map1->FeatureFactory->CreateCircularRegion(miCircleTypeMap, point, Variant(30),  EmptyParam, Variant(99), EmptyParam);
      Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);
      strFeature = "似圓的區域";}
      break;
    case 2: {
      //這樣做， 在退出程序時，會報異常
      CMapXFeatureDisp line;
      line.Bind(StringToOleStr("MapX.Feature.5"));
      line.Attach(Map1->OleObject);
      line.Type = miFeatureTypeLine;
      line.Style = Map1->DefaultStyle;

      CMapXPointsDisp points;
      points.Bind(StringToOleStr("MapX.Points.5"));
      double x =  point.get_X();
      double y =  point.get_Y();
      points.AddXY(x - 1, y - 0.5);
      points.AddXY(x - 0.5, y + 0.5);
      points.AddXY(x, y);
      points.AddXY(x + 0.5, y - 0.5);
      points.AddXY(x + 1, y + 0.5);
      line.Parts->Add(points);

      //feature = Map1->FeatureFactory->CreateLine(EmptyParam, EmptyParam);
      Map1->Layers->_Item(Variant(1))->AddFeature(line, EmptyParam);
      line->Attach(NULL);
      strFeature = "線, 退出會異常，請用添加區域的方法";}
      break;
    case 3: {
      CMapXPointsDisp points;
      points.Bind(StringToOleStr("MapX.Points.5"));
      double x =  point.get_X();
      double y =  point.get_Y();
      points.AddXY(x - 1, y - 0.5);
      points.AddXY(x - 0.2, y + 0.7);
      points.AddXY(x + 0.3, y - 0.1);
      points.AddXY(x + 0.8, y + 0.6);

      feature = Map1->FeatureFactory->CreateRegion(EmptyParam, EmptyParam);
      feature->Parts->Add(points);
      Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);
      strFeature = "區域圖元";}
      break;
    case 4: {
      feature = Map1->FeatureFactory->CreateSymbol(EmptyParam, EmptyParam);
      feature->set_Point(point);
      Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);
      strFeature = "點圖元";}
      break;
    case 5: {
      Variant caption = "文本圖元abcdefg";
     caption.ChangeType(0x8);
     feature = Map1->FeatureFactory->CreateText(EmptyParam, caption, EmptyParam, EmptyParam);
      feature->set_Point(point);
      Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);
      strFeature = "文本圖元";}
      break;

    default:
    ;
  }
  placeFeatureId = -1;
  log("日誌", strFeature + "位置 x:" + String(point.get_X()) + " y:" + String(point.get_Y()) +( feature == NULL ?" faile":" secc"));