MapX常用功能代码逻辑

本文主要是介绍MapX常用功能代码逻辑，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

例程参见DET中的CMapXOP类和CRoadAttrCompReplaceDlg类。

1. 创建控件

   if ( !CMapX::Create( lpszWindowName , dwStyle , rect ,pParentWnd , nID , pPersist , bStorage , bstrLicKey ) )
return FALSE;
CMapX::SetMapUnit( miUnitMeter );
CMapX::SetAreaUnit( miUnitSquareMeter );
CMapX::SetDefaultConversionResolution(100);
CMapX::SetMousewheelSupport( miFullMousewheelSupport );
CMapX::GetLayers().RemoveAll();
CMapXCoordSys cs = CMapX::GetDisplayCoordSys();
double y = cs.GetOriginLatitude();
double x = cs.GetOriginLongitude();
short s = cs.GetType();
CMapXRectangle Rect;
CMapXCoordSys CurrentCoordsys;
COptionalVariant vEmpty; 
VARIANT MapUnit,MapBounds;
if(!Rect.CreateDispatch(Rect.GetClsid()))
{
TRACE0("Could not Create object"); 
} 
if(!CurrentCoordsys.CreateDispatch(CurrentCoordsys.GetClsid())) 
{
TRACE0("Could not Create object"); 
} 
MapUnit.vt=VT_I4;
MapUnit.lVal=miUnitMeter; 
//设置坐标范围(MBR).为求一致，这里取当GeosetManager中设置为non-earth(meters)时,
//gst文件中的参数"\GEOSET\MBR\LOWERLEFT" ,"\GEOSET\MBR\UPPERRIGHT"。
Rect.Set( 0,0,180,90 );
MapBounds.vt=VT_DISPATCH;
MapBounds.pdispVal=Rect.m_lpDispatch;
MapBounds.pdispVal->AddRef(); 
// 经纬度投影
CMapXDatum datum;
datum.CreateDispatch( datum.GetClsid() );
datum.Set( 28,0,0,0,0,0,0,0,0 );
CurrentCoordsys.Set( miLongLat, datum,MapUnit,
vEmpty, vEmpty, vEmpty,vEmpty, vEmpty, 
vEmpty, vEmpty, vEmpty, vEmpty,MapBounds, vEmpty);
CMapX::SetNumericCoordSys(CurrentCoordsys.m_lpDispatch);
CMapX::SetDisplayCoordSys(CMapX::GetNumericCoordSys().m_lpDispatch); 
CMapX::SetTitleText( _T("") );

2.加载图层

    CMapXLayer lyrTemp = CMapX::GetLayers().Add( tcsTbFile );
    VARIANT vr;
    vr.vt = VT_DISPATCH;
    vr.pdispVal = lyrTemp;
    CMapX::GetDatasets().Add( miDataSetLayer , vr , lyrTemp.GetName() );

3.卸载图层

m_pMapXOP->GetDatasets().Remove(_T("navi_arc"));
m_pMapXOP->GetLayers().Remove(_T("navi_arc"));

4.读取属性值

(1) 整型字段值

       //cd traffic flow
       VARIANT var = rowvlus_cd.Item(_T("TrafficFlo")).GetValue();
       int iTrfcFlw = var.dblVal;

(2)字符串型字段值
      //sw direction
       VARIANT var1 = rowvlus_sw.Item(_T("Direction")).GetValue();
       string strdir = m_StringOp.ConverVariantToMBCS(var1);

5.更新属性值

(1) 获取到要更新的图层的rowvalues

CMapXRowValues rowvlus_cd = dstNavi_cd.GetRowValues(k);

(2)更新相应的字段值

rowvlus_cd.Item(_T("TrafficFlo")).SetValue( COleVariant(long(iTrfcFlw)) );
ftr_cd.Update( true, rowvlus_cd );

6.创建新表

 //创建空字段对象

CMapXFields Flds;
if(!Flds.CreateDispatch(Flds.GetClsid()))
{
TRACE0("failed to create Flds");
return 0;
}

 //根据字段类型在空对象中加入字段
switch( fieldType )
{
case miTypeString:
{
int width = appendField.fieldWidth;
Flds.AddStringField( lpszFileName , width );
break;
}
case miTypeNumeric:
{
Flds.AddNumericField( lpszFileName , 11 , 2 );
break;
}
case miTypeDate:
{
Flds.AddDateField( lpszFileName );
break; 
}
case miTypeInteger:
case miTypeSmallInt:
{
Flds.AddIntegerField( lpszFileName );
break;
}
case miTypeFloat:
{
Flds.AddFloatField( lpszFileName );
break;
}
case miTypeLogical:
{
Flds.AddLogicalField( lpszFileName );
break;
}

  CMapXLayerInfo LayerInfo;
if(!LayerInfo.CreateDispatch(LayerInfo.GetClsid()))
{
TRACE0("Failed to create LayerInfo");
return 0;
}

  LayerInfo.SetType( miLayerInfoTypeNewTable );
lpszFileName = pStringOp->ConvertMcbsToWideChar( lpBuffer );
LayerInfo.AddParameter( _T("FileSpec"),COleVariant( lpszFileName ));
lpszFileName = pStringOp->ConvertMcbsToWideChar( ptcsElemName );
LayerInfo.AddParameter(_T("Name"),COleVariant( lpszFileName ) );

  VARIANT vtFlds;
vtFlds.vt = VT_DISPATCH;
vtFlds.pdispVal = Flds.m_lpDispatch;

  LayerInfo.AddParameter(_T("Fields"),vtFlds);
  //UnloadMap();
lyr = CMapX::GetLayers().Add(LayerInfo.m_lpDispatch);
vr.pdispVal = lyr;   
CMapX::GetDatasets().Add( miDataSetLayer,vr,lpszFileName );

7.紧缩表

（1）、将以下申明加入例子自带的MapX.h，位置在CMapXLayer类申明的Operations之Public:中即可
BOOL SupportsPack(long PackType);//sdy080520
void Pack(long PackType);//sdy080520

（2）、将以下声明加入例子自带的MapX.h的对应位置（最上边有一处是专门声明enum的，放在那个位置即可）
enum LayerPackConstants
{
               miPackGraphics = 1,
miRebuildGraphics = 2,
miPackIndex = 4,
miPackRebuildIndex = 8,
miPackData = 16,
miPackCompactDB = 32,
miPackAll = 21 //miPackGraphics & miPackIndex & miPackData;
};   //sdy080520

（3）、将以下代码加入例子自带的MapX.cpp
BOOL CMapXLayer::SupportsPack(long PackType)//sdy080520
{
BOOL result;
static BYTE parms[] =
   VTS_I4;
InvokeHelper(0x35, DISPATCH_METHOD, VT_BOOL, (void*)&result, parms,
   PackType);
return result;
}
void CMapXLayer::Pack(long PackType)//sdy080520
{
static BYTE parms[] =
   VTS_I4;
InvokeHelper(0x36, DISPATCH_METHOD, VT_EMPTY, NULL, parms,
   PackType);
}

（4）、使用方式
CMapXLayer layer = m_ctrlMapX.GetLayers().Item(index);
layer.Pack(miPackAll);