在要素数据集中创建要素类

public IFeatureClass IFeatureDataset__CreateFeatureClass(IFeatureDataset featureDataset, String nameOfFeatureClass)

{



// This function creates a new feature class in a supplied feature dataset by building all of the

// fields from scratch. IFeatureClassDescription (or IObjectClassDescription if the table is 

  // created at the workspace level) can be used to get the required fields and are used to 

  // get the InstanceClassID and ExtensionClassID.

// Create new fields collection with the number of fields you plan to add. Must add at least two fields

// for a feature class: Object ID and Shape field.

IFields fields = new FieldsClass();

IFieldsEdit fieldsEdit = (IFieldsEdit)fields;

fieldsEdit.FieldCount_2 = 3;



// Create Object ID field.

IField fieldUserDefined = new Field();



IFieldEdit fieldEdit = (IFieldEdit)fieldUserDefined;

fieldEdit.Name_2 = "OBJECTID";

fieldEdit.AliasName_2 = "OBJECT ID";

fieldEdit.Type_2 = esriFieldType.esriFieldTypeOID;

fieldsEdit.set_Field(0, fieldUserDefined);



// Create Shape field.

fieldUserDefined = new Field();

fieldEdit = (IFieldEdit)fieldUserDefined;



// Set up geometry definition for the Shape field.

// You do not have to set the spatial reference, as it is inherited from the feature dataset.

IGeometryDef geometryDef = new GeometryDefClass();

IGeometryDefEdit geometryDefEdit = (IGeometryDefEdit)geometryDef;

geometryDefEdit.GeometryType_2 = ESRI.ArcGIS.Geometry.esriGeometryType.esriGeometryPolyline;



// By setting the grid size to 0, you are allowing ArcGIS to determine the appropriate grid sizes for the feature class. 

// If in a personal geodatabase, the grid size is 1,000. If in a file or ArcSDE geodatabase, the grid size

// is based on the initial loading or inserting of features.

geometryDefEdit.GridCount_2 = 1;

geometryDefEdit.set_GridSize(0, 0);

geometryDefEdit.HasM_2 = false;

geometryDefEdit.HasZ_2 = false;



// Set standard field properties.

fieldEdit.Name_2 = "SHAPE";

fieldEdit.Type_2 = esriFieldType.esriFieldTypeGeometry;

fieldEdit.GeometryDef_2 = geometryDef;

fieldEdit.IsNullable_2 = true;

fieldEdit.Required_2 = true;

fieldsEdit.set_Field(1, fieldUserDefined);



// Create a field of type double to hold some information for the features.

fieldUserDefined = new Field();



 fieldEdit = (IFieldEdit)fieldUserDefined;

fieldEdit.Name_2 = "Avg_income";

fieldEdit.AliasName_2 = "Average income for 1999-2000";

fieldEdit.Editable_2 = true;

fieldEdit.IsNullable_2 = false;

fieldEdit.Precision_2 = 2;

fieldEdit.Scale_2 = 5;

fieldEdit.Type_2 = esriFieldType.esriFieldTypeDouble;

fieldsEdit.set_Field(2, fieldUserDefined);



// Create a feature class description object to use for specifying the CLSID and EXTCLSID.

IFeatureClassDescription fcDesc = new FeatureClassDescriptionClass();

IObjectClassDescription ocDesc = (IObjectClassDescription)fcDesc;



return featureDataset.CreateFeatureClass(nameOfFeatureClass, fields, ocDesc.InstanceCLSID, ocDesc.ClassExtensionCLSID, esriFeatureType.esriFTSimple, "SHAPE", "");



}