//featureClass是自己获取的featureClass，也可是sde中获取的。                  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;           }