学步园

1. 大家可能在平时开发中可能会遇到按行政区加载图层数据的需求，比方说整个国土资源部有某一类型专题数据有若干图层，每个图层数据的范围是整个中国，这时国土资源部开发一套系统可能有这个需求，每个省只能加载本省的数据。以下函数即为按按行政区范围创建行政区范围的图层。   
2. 比方说我想获取河南省的数据只需传入行政区图层中河南省图元的Geometry即可。另外如果如果遇到行政区层必须用 esriSpatialRelEnum.esriSpatialRelContains这个参数，否则行政区这个图层就不能只获取河南这个省份，它会把河南省的周围省份，河北，湖北，安徽，陕西，山东，山西等省份的图元也添加创建到新图层。   
3.         /// <summary>   
4.         /// 按行政区范围创建行政区范围的图层   
5.         /// </summary>   
6.         /// <param name="pFeatureLayer">源数据图层</param>   
7.         /// <param name="pGeometry">行政区范围</param>   
8.         /// <param name="bXZQ">图层是否为行政区</param>   
9.         /// <returns>新创建的图层</returns>   
10.         private IFeatureLayer  GetSelectionLayer(IFeatureLayer pFeatureLayer, IGeometry pGeometry,bool bXZQ)   
11.         {   
12.             try  
13.             {   
14.                 if (pFeatureLayer != null && pGeometry != null)   
15.                 {   
16.                     IQueryFilter pQueryFilter;   
17.                     ISpatialFilter pSpatialFilter = new SpatialFilterClass();   
18.                     IFeatureSelection pFeatureSelection = pFeatureLayer as IFeatureSelection;   
19.                     pSpatialFilter.GeometryField = pFeatureLayer.FeatureClass.ShapeFieldName;   
20.                     pFeatureSelection.Clear();                     
21.                     if (!bXZQ)   
22.                     {   
23.                         pSpatialFilter.Geometry = pGeometry;                         
24.                         pSpatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects;   
25.                         pQueryFilter = pSpatialFilter;                          
26.                         pFeatureSelection.SelectFeatures(pQueryFilter, esriSelectionResultEnum.esriSelectionResultNew, false);   
27.                     }   
28.                     else  
29.                     {   
30.                         pSpatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelContains;   
31.                         pQueryFilter = pSpatialFilter;                          
32.                         if(pGeometry is IGeometryCollection)   
33.                         {   
34.                             for (int i = 0; i < (pGeometry as IGeometryCollection).GeometryCount; i++)   
35.                             {   
36.                                 pSpatialFilter.Geometry = (pGeometry as IGeometryCollection).get_Geometry(i);    
37.                                 pFeatureSelection.SelectFeatures(pQueryFilter, esriSelectionResultEnum.esriSelectionResultAdd, false);   
38.                             }   
39.                         }   
40.                     }                    
41.                     IFeatureLayerDefinition pFLDefinition = pFeatureLayer as IFeatureLayerDefinition;   
42.                     IFeatureLayer pNewFeatureLayer = pFLDefinition.CreateSelectionLayer(pFeatureLayer.Name ,true, null, null);   
43.                     pNewFeatureLayer.MaximumScale = pFeatureLayer.MaximumScale;   
44.                     pNewFeatureLayer.MinimumScale = pFeatureLayer.MinimumScale;   
45.                     pNewFeatureLayer.Selectable = pFeatureLayer.Selectable;   
46.                     pNewFeatureLayer.Visible = pFeatureLayer.Visible;   
47.                     pNewFeatureLayer.ScaleSymbols = pFeatureLayer.ScaleSymbols;   
48.                     return pNewFeatureLayer;   
49.                 }   
50.                 else  
51.                 {   
52.                     return null;   
53.                 }   
54.             }   
55.             catch (Exception Err)   
56.             {   
57.                 MessageBox.Show(Err.Message, "获取SelectionLayer", MessageBoxButtons.OK, MessageBoxIcon.Information);   
58.                 return null;   
59.             }   
60.         }   
61.            
62.     }