風過無痕 原文? arcengine,深入理解游標Cursors，實現數據的快速查找，插入，刪除，更新

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深入理解游標Cursors，實現數據的快速查找，插入，刪除，更新

1、查找數據Search Cursors

//by yl landgis@126.com yanleigis@21cn.com 2008.7.7

IEnvelope envelope = new EnvelopeClass(); envelope.PutCoords(508786, 681196, 513033, 684341); ISpatialFilter spatialFilter = new SpatialFilterClass(); spatialFilter.Geometry = envelope; String shpFld = featureClass.ShapeFieldName; spatialFilter.GeometryField = shpFld; spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects; IQueryFilter queryFilter = new QueryFilterClass(); queryFilter = (IQueryFilter)spatialFilter;IFeatureCursor searchCursor = featureClass.Search(queryFilter, true);//只查詢，true快一些 IFeature feature = searchCursor.NextFeature(); int n = 0; while (feature != null){n++;feature = baseCursor.NextFeature(); }

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2、插入數據Insert Cursors—目前數據插入最快的方法 ??

//by yl landgis@126.com yanleigis@21cn.com 2008.7.7

IFeatureBuffer featureBuffer = featureClass.CreateFeatureBuffer(); IFeatureCursor featureCursor = featureClass.Insert(true); object featureOID; featureBuffer.set_Value(featureBuffer.Fields.FindField("InstBy"), "B Pierce");for (int ic = 0; ic < 99; ic++) { featureBuffer.Shape = geometryfeatureOID = featureCursor.InsertFeature(featureBuffer); }featureBuffer.set_Value(featureBuffer.Fields.FindField("InstBy"), "K Johnston");for (int ic = 0; ic < 99; ic++) {featureBuffer.Shape = geometryfeatureOID = featureCursor.InsertFeature(featureBuffer); }featureCursor.Flush();

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3、 數據刪除 delete ??

//by yl landgis@126.com yanleigis@21cn.com 2008.7.7

IFeatureClass featureClass = featureWorkspace.OpenFeatureClass("Parcels");IQueryFilter queryFilter = new QueryFilterClass(); queryFilter.WhereClause = "ZONING_S = 'R'"; IFeatureCursor updateCursor = featureClass.Update(queryFilter, false);IFeature feature = updateCursor.NextFeature();int m = 0; while (feature != null) {m++;updateCursor.DeleteFeature(feature);feature = updateCursor.NextFeature(); }

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4、數據更新 update ??

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//by yl landgis@126.com yanleigis@21cn.com 2008.7.7 IFeatureClass featureClass = featureWorkspace.OpenFeatureClass("Parcels");// restrict the number of features to be updated. IQueryFilter queryFilter = new QueryFilterClass(); queryFilter.WhereClause = "ZONING_S = 'U'";// use IFeatureClass::Update to populate IFeatureCursor IFeatureCursor updateCursor = featureClass.Update(queryFilter, false); int fieldindex = featureClass.FindField("ZONING_S"); IFeature feature = updateCursor.NextFeature();int m = 0; while (feature != null) {m++;feature.set_Value(fieldindex, "X");updateCursor.UpdateFeature(feature);feature = updateCursor.NextFeature(); }

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轉載于:https://www.cnblogs.com/arxive/p/6114330.html

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