原文链接：http://gishuangjun.blog.sohu.com/139347305.html
核心提示：arcEngine9.2中新增了一个新的特征，允许创建内存工作空间。
arcEngine9.2中新增了一个新的特征，允许创建内存工作空间。当你需要一个这样的图层时,这个图层的属性数据或者几何数据需要频繁的更新，而又不希望因此而带来效率上的问题，你就可以考虑使用内存图层。
内存图层的创建分为五步：
1、设置属性字段
2、设置空间参考和几何字段
3、创建内存工作空间
4、在内存工作空间中创建特征类
5、创建特征图层，并将上一步创建的特征类设置为这个特征的图层的特征类
请看以下完整的示例代码
/// <summary>
/// 在内存中创建图层
/// </summary>
/// <param name="DataSetName">数据集名称</param>
/// <param name="AliaseName">别名</param>
/// <param name="SpatialRef">空间参考</param>
/// <param name="GeometryType">几何类型</param>
/// <param name="PropertyFields">属性字段集合</param>
/// <returns>IfeatureLayer</returns>
public static IFeatureLayer CreateFeatureLayerInmemeory(string DataSetName, string AliaseName, ISpatialReference SpatialRef, esriGeometryType GeometryType, IFields PropertyFields)
{
IWorkspaceFactory workspaceFactory = new InMemoryWorkspaceFactoryClass();
ESRI.ArcGIS.Geodatabase.IWorkspaceName workspaceName = workspaceFactory.Create("", "MyWorkspace", null, 0);
ESRI.ArcGIS.esriSystem.IName name = (IName)workspaceName;
ESRI.ArcGIS.Geodatabase.IWorkspace inmemWor = (IWorkspace)name.Open();
IField oField = new FieldClass();
IFields oFields = new FieldsClass();
IFieldsEdit oFieldsEdit = null;
IFieldEdit oFieldEdit = null;
IFeatureClass oFeatureClass = null;
IFeatureLayer oFeatureLayer = null;
try
{
oFieldsEdit = oFields as IFieldsEdit;
oFieldEdit = oField as IFieldEdit;
for (int i = 0; i < PropertyFields.FieldCount; i++)
{
oFieldsEdit.AddField(PropertyFields.get_Field(i));
}
IGeometryDef geometryDef = new GeometryDefClass();
IGeometryDefEdit geometryDefEdit = (IGeometryDefEdit)geometryDef;
geometryDefEdit.AvgNumPoints_2 = 5;
geometryDefEdit.GeometryType_2 = GeometryType;
geometryDefEdit.GridCount_2 = 1;
geometryDefEdit.HasM_2 = false;
geometryDefEdit.HasZ_2 = false;
geometryDefEdit.SpatialReference_2 = SpatialRef;
oFieldEdit.Name_2 = "SHAPE";
oFieldEdit.Type_2 = esriFieldType.esriFieldTypeGeometry;
oFieldEdit.GeometryDef_2 = geometryDef;
oFieldEdit.IsNullable_2 = true;
oFieldEdit.Required_2 = true;
oFieldsEdit.AddField(oField);
oFeatureClass = (inmemWor as IFeatureWorkspace).CreateFeatureClass(DataSetName, oFields, null, null, esriFeatureType.esriFTSimple, "SHAPE", "");
(oFeatureClass as IDataset).BrowseName = DataSetName;
oFeatureLayer = new FeatureLayerClass();
oFeatureLayer.Name = AliaseName;
oFeatureLayer.FeatureClass = oFeatureClass;
}
catch
{
}
finally
{
try
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(oField);
System.Runtime.InteropServices.Marshal.ReleaseComObject(oFields);
System.Runtime.InteropServices.Marshal.ReleaseComObject(oFieldsEdit);
System.Runtime.InteropServices.Marshal.ReleaseComObject(oFieldEdit);
System.Runtime.InteropServices.Marshal.ReleaseComObject(name);
System.Runtime.InteropServices.Marshal.ReleaseComObject(workspaceFactory);
System.Runtime.InteropServices.Marshal.ReleaseComObject(workspaceName);
System.Runtime.InteropServices.Marshal.ReleaseComObject(inmemWor);
System.Runtime.InteropServices.Marshal.ReleaseComObject(oFeatureClass);
}
catch { }
GC.Collect();
}
return oFeatureLayer;
}
下面就是根据采集的坐标点创建点内存图层：
IFeatureLayer pFeatureLayer = new FeatureLayerClass();
IFieldsEdit curFileds = new FieldsClass();
IFieldEdit curField = new FieldClass();
curField = new FieldClass();
curField.Name_2 = "名称";
curField.Type_2 = esriFieldType.esriFieldTypeString;
curFileds.AddField(curField);
curField = new FieldClass();
curField.Name_2 = "经度";
curField.Type_2 = esriFieldType.esriFieldTypeDouble;
curFileds.AddField(curField);
curField = new FieldClass();
curField.Name_2 = "纬度";
curField.Type_2 = esriFieldType.esriFieldTypeDouble;
curFileds.AddField(curField);
pFeatureLayer = CreateFeatureLayerInmemeory("Position", "采集点", new UnknownCoordinateSystemClass(), esriGeometryType.esriGeometryPoint, curFileds as IFields);
p_axMap.AddLayer(pFeatureLayer as ILayer);
IFeatureCursor FeatureCursor;
IFeature pFeature;
IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;
pFeature = pFeatureClass.CreateFeature();
IQueryFilter pQueryFilter = new QueryFilterClass();
FeatureCursor = pFeatureClass.Search(pQueryFilter, true);
pQueryFilter.WhereClause = null;
pFeature = FeatureCursor.NextFeature();
pFeature.set_Value(0, str1);
pFeature.set_Value(1, x);
pFeature.set_Value(2, y);
IEnvelope pEnvelope = new EnvelopeClass();
//如果双击的对象是一个点，这样子才能够缩放到该点
pEnvelope.PutCoords(0, 0, 0.3, 0.3);//确定ｅｎｖｅｌｏｐｅ大小
IPoint xpoint = new PointClass();
xpoint.PutCoords(x, y);
pFeature.Shape = xpoint;
pFeature.Store();
//设置颜色
IRgbColor pcolor = new RgbColorClass();
pcolor.Red = 255;
pcolor.Green = 0;
pcolor.Blue = 0;
//设置图形
ISimpleMarkerSymbol psm = new SimpleMarkerSymbolClass();
psm.Style = esriSimpleMarkerStyle.esriSMSCircle;
psm.Size = 10;
psm.Color = pcolor;
(pFeatureLayer as IFeatureSelection).SelectionSymbol = (ISymbol)psm;
(pFeatureLayer as IFeatureSelection).SetSelectionSymbol = true;
(pFeatureLayer as IFeatureSelection).SelectionSet.Add(pFeature.OID);
pEnvelope.CenterAt(xpoint);//地图缩放到该点
p_axMap.Extent = pEnvelope;
p_axMap.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeography, pFeatureLayer, null);
p_axMap.ActiveView.ScreenDisplay.UpdateWindow();
