C++ Builder中实现MAPX的Feature

昨天试了一天的Feature,现在还存在的问题有：

1)无法将CMapX***Disp 转换成 tagVariant, 例如例子中，创建线及区域时， 无论你写成下面的任何一种，都创建不成功，

Map1->Layers->_Item(Variant(1))->CreateRegion(points, EmptyParam);//编译失败

Map1->Layers->_Item(Variant(1))->CreateRegion(Variant((IUnknown *)points), EmptyParam);//运行创建不成功

而只好改用下面的两行代码：

feature = Map1->FeatureFactory->CreateRegion(EmptyParam, EmptyParam);

feature->Parts->Add(points);

2)下面的示例中保留了一个错误，就是用 下面的代码创建Feature时，程序退出会抛出异常。现在还没找到解决的方法，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);

示例代码：

void __fastcall TfrmFeature::Map1MouseUp(TObject *Sender,

TMouseButton Button, TShiftState Shift, int X, int Y)

{ //只向 动画层中加图元

if((Button != mbLeft) || (placeFeatureId == -1)) return;

if(Map1->Layers->Count == 0 ){

log("日志", "没有图层或动画图层， 不能完成添加Feature的工作");

placeFeatureId = -1;

return;

}

//动作名称

String strFeature;

CMapXPointDisp point;

//生成的图元

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 = "形似弧的线图元";}

break;

case 1:{

feature = Map1->FeatureFactory->CreateCircularRegion(miCircleTypeMap, point, Variant(30), EmptyParam, Variant(99), EmptyParam);

Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);

strFeature = "似圆的区域";}

break;

case 2: {

//这样做， 在退出程序时，会报异常

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 = "线, 退出会异常，请用添加区域的方法";}

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 = "区域图元";}

break;

case 4: {

feature = Map1->FeatureFactory->CreateSymbol(EmptyParam, EmptyParam);

feature->set_Point(point);

Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);

strFeature = "点图元";}

break;

case 5: {

feature = Map1->FeatureFactory->CreateText(EmptyParam, Variant("Hello"), EmptyParam, EmptyParam);

feature->set_Point(point);

Map1->Layers->_Item(Variant(1))->AddFeature(feature, EmptyParam);

strFeature = "文本图元";}

break;

default:

;

}

placeFeatureId = -1;

log("日志", strFeature + "位置 x:" + String(point.get_X()) + " y:" + String(point.get_Y()) +( feature == NULL ?" faile":" secc"));