ArcGIS Engine开发（1）：从零开始

ArcGIS Engine开发

• 一、要素的类型 esriFeatureType 二、esriFeatureType与esriGeometryType的区别与联系 三、Arcgis Engine 接口说明（转） 四、esriFieldType 要素字段类型 五、读取FeatureClass的字段 六、获取Feature的点集 七、读取FeatureClass的字段 八、复制字段名称

适合新入门小白查看，花了1周时间理解ArcGIS Engine内部工作空间、要素工作空间、要素 类  、要素等关系，还有GDB、MDB、Shapefile的读取与写入。

一、要素的类型 esriFeatureType

//pFeatureClass为IFeatureClass对象，获取要素类型
esriFeatureType type = pFeatureClass.FeatureType;
public enum esriFeatureType
    {
        esriFTSimple = 1,
        esriFTSimpleJunction = 7,
        esriFTSimpleEdge = 8,
        esriFTComplexJunction = 9,
        esriFTComplexEdge = 10,
        esriFTAnnotation = 11,
        esriFTCoverageAnnotation = 12,
        esriFTDimension = 13,
        esriFTRasterCatalogItem = 14
}

二、esriFeatureType与esriGeometryType的区别与联系

1. esriFeatureType通常用来表示数据的存储结构，即物理层；
2. esriGeometryType通常用来表示数据的几何形状，即表现层。构成了图形的基本类型。

esriGeometryType枚举类型 详解

看图：

三、Arcgis Engine 接口说明（转）

链接: 接口说明。

四、esriFieldType 要素字段类型

namespace ESRI.ArcGIS.Geodatabase
{
    [Guid("4CA2D959-5A38-11D2-AABD-00C04FA37585")]
    public enum esriFieldType
    {
        esriFieldTypeSmallInteger = 0,
        esriFieldTypeInteger = 1,
        esriFieldTypeSingle = 2,
        esriFieldTypeDouble = 3,
        esriFieldTypeString = 4,
        esriFieldTypeDate = 5,
        esriFieldTypeOID = 6,
        esriFieldTypeGeometry = 7,
        esriFieldTypeBlob = 8,
        esriFieldTypeRaster = 9,
        esriFieldTypeGUID = 10,
        esriFieldTypeGlobalID = 11,
        esriFieldTypeXML = 12
    }
}

五、读取FeatureClass的字段

FeatureClass中存储字段名称，Feature中存储字段值，字段值是每个Feature的属性。

   IFields fieldsSrc = pFeatureCls.Fields;
  string mf = "";
  string mf2 = "";
  for (int ii = 0; ii < fieldsSrc.FieldCount; ii++)
  {
      mf += fieldsSrc.Field[ii].Name + "\r\n";  //第几个参数
      mf2 += fieldsSrc.Field[ii].AliasName + "\r\n";  //第几个参数
  }

获取要素字段值
int cnt = pFeature.Fields.FieldCount;
  for (int ii = 0; ii < fieldsSrc.FieldCount; ii++)
  {
      textboxLogShow(pFeature.get_Value(ii).ToString());
  }

六、获取Feature的点集

1. 获取要素的图形

   IGeometry pGeo = pFeature.ShapeCopy;

• 点

IPoint ptSrc = pGeo as IPoint;
IPointCollection pc = pGeo as IPointCollection;

• 线:

pointCollection = new PolylineClass();
IPolyline polyline = pGeo as IPolyline;
pointCollection = polyline as IPointCollection;

• 面:
  ：这种方法只适用于只有一个的面，即只有1个面，面内没有被挖去的部分，面外也没有其他的填充面，也就是说只有一个外部Ring。

IGeometry pGeo = pFeatureClass.ShapeCopy;
  pointCollection = pGeo as IPointCollection;
  //坐标转换
  for (int j2 = 0; j2 < pointCollection.PointCount; j2++)
  {
      ptSrc = new PointClass();
      pointCollection.QueryPoint(j2, ptSrc);
      /*
      Work!
      */
      pointCollection.UpdatePoint(j2, ptCal);
  }
  pGeo = ClsArcGIS.GetPolygonGeometry(pointCollection);
  pFeature.Shape = pGeo;

：面对象是一个，面中外部Ring方向是顺时针，内部Ring方向是逆时针，不存在面积为0的Ring.所以获取面对象 坐标 ，就要获取面的内部和外部所有Ring对象即可。

//遍历找出面的内外部Ring:
  Dictionary<IRing, List<IRing>> dicRings = new Dictionary<IRing, List<IRing>>();
  IGeometry pShape = null;
  esriGeometryType pGeoType = pGeo.GeometryType;

  try
  {
      IPolygon4 polygon = pGeo as IPolygon4;
      //外环个数
      int exRingCount = polygon.ExteriorRingCount;
      IGeometryBag exteriorRings = polygon.ExteriorRingBag;

      //For each exterior rings find the interior rings associated with it 
      IEnumGeometry exteriorRingsEnum = exteriorRings as IEnumGeometry;
      exteriorRingsEnum.Reset();
      IRing currentExteriorRing = exteriorRingsEnum.Next() as IRing;
      
      while (currentExteriorRing != null)
      {
          if (!dicRings.ContainsKey(currentExteriorRing))
          {
    dicRings[currentExteriorRing] = new List<IRing>();
          }
          
          IGeometryBag interiorRings = polygon.get_InteriorRingBag(currentExteriorRing);
          IEnumGeometry interiorRingsEnum = interiorRings as IEnumGeometry;
          interiorRingsEnum.Reset();
          IRing currentInteriorRing = interiorRingsEnum.Next() as IRing;
          while (currentInteriorRing != null)
          {
    dicRings[currentExteriorRing].Add(currentInteriorRing);
    currentInteriorRing = interiorRingsEnum.Next() as IRing;
          }
          currentExteriorRing = exteriorRingsEnum.Next() as IRing;
      }

七、读取FeatureClass的字段

FeatureClass中存储字段名称，Feature中存储字段值，字段值是每个Feature的属性。

  IFields fieldsSrc = pFeatureCls.Fields;
  string mf = "";
  string mf2 = "";
  for (int ii = 0; ii < fieldsSrc.FieldCount; ii++)
  {
      mf += fieldsSrc.Field[ii].Name + "\r\n";  //第几个参数
      mf2 += fieldsSrc.Field[ii].AliasName + "\r\n";  //第几个参数
  }

//获取要素字段值
int cnt = pFeature.Fields.FieldCount;
  for (int ii = 0; ii < fieldsSrc.FieldCount; ii++)
  {
      textboxLogShow(pFeature.get_Value(ii).ToString());
  }

八、复制字段名称

：首先获取要素类的字段集合，然后遍历字段，添加到新的IFields中。

 #region 获取属性字段 Method 1
 IGeometryDefEdit geomDefEdit = null;
 IFields pFields = pFeatCls.Fields;
 IFields pNewFields = new FieldsClass();
 IFieldsEdit pNewFieldsEdit = pNewFields as IFieldsEdit;

 //保证源要素类与新要素类的字段结构一致，但空间范围不一样，即自己手动设计Geometry字段
 for (int i = 0; i < pFields.FieldCount; i++)
 {
     pField = pFields.get_Field(i);
     if (pField.Type != esriFieldType.esriFieldTypeGeometry)
     {
         pNewFieldsEdit.AddField(pField);
     }
     else
     {
         pGeoField = pField;
         geomDefEdit = pGeoField.GeometryDef as IGeometryDefEdit;
         geomDefEdit.SpatialReference_2 = pSpatialReference;
         pNewFieldsEdit.AddField(pGeoField);
     }
 }
 #endregion

：通过字段IFieldChecker ，获得原有要素类的所有字段。

 #region 获取属性字段 Method 2
 //属性信息
 // 创建字段检查对象
 IWorkspace pTWorkspace = pWorkspace as IWorkspace;
 IFieldChecker pFieldChecker = new FieldCheckerClass();
 IEnumFieldError pEnumFieldError = null;
 IFields fieldsTar;
 pFieldChecker.ValidateWorkspace = pTWorkspace;
 pFieldChecker.Validate(pFeatCls.Fields, out pEnumFieldError, out fieldsTar);
 #endregion



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