IFeatureLayerDefinition接口实现IFeatureLayer图层显示过滤，图层全范围视图的获取

 public void FilterAndZoomToLayer(IFeatureClass featureClass)
          {
                    IFeatureLayer featureLayer = new FeatureLayerClass();
                    featureLayer.FeatureClass = featureClass;
                    IFeatureLayerDefinition featureLayerDefinition = featureLayer as IFeatureLayerDefinition;
                    //获取符合条件的图层要素
                    featureLayerDefinition.DefinitionExpression = "XZQDM like '" + xz_xzqdm + "%'";
                    IFeatureLayer newFeatureLayer = featureLayerDefinition.CreateSelectionLayer(featureClass.AliasName, false, null, featureLayerDefinition.DefinitionExpression);
                  
                     ILayer newLayer = newFeatureLayer as ILayer;
                     mcView.AddLayer(newLayer);
 
                    //实现过滤后的图层，缩放到图层
                    IEnvelope envelope = new EnvelopeClass();
                    ILayer layer = mcView.get_Layer(0);
                    IFeatureLayer featureLayer = layer as IFeatureLayer;
                    IQueryFilter queryFilter = new QueryFilterClass();
                    queryFilter.WhereClause = "";
                    IFeatureCursor featureCursor = featureLayer.FeatureClass.Search(queryFilter, true);
                    IFeature feature = featureCursor.NextFeature();
                    while (feature != null)
                    {
                        IGeometry geometry = feature.Shape;
                        IEnvelope featureExtent = geometry.Envelope;
                        envelope.Union(featureExtent);
                        System.Runtime.InteropServices.Marshal.ReleaseComObject(feature);
                        feature = featureCursor.NextFeature();
                    }
                    mcView.ActiveView.FullExtent  = envelope;
           } public void FilterAndZoomToLayer(IFeatureClass