风过无痕原文 arcengine,深入理解游标Cursors,实现数据的快速查找,插入,删除,更新
深入理解游标Cursors,实现数据的快速查找,插入,删除,更新
1、查找数据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);//只查询,true快一些
IFeature feature = searchCursor.NextFeature();
int n = 0;
while (feature != null){
n++;
feature = baseCursor.NextFeature();
}
2、插入数据Insert Cursors—目前数据插入最快的方法
//by yllandgis@126.com yanleigis@21cn.com2008.7.7
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 = geometry
featureOID = featureCursor.InsertFeature(featureBuffer);
}
featureBuffer.set_Value(featureBuffer.Fields.FindField("InstBy"), "K Johnston");
for (int ic = 0; ic < 99; ic++)
{
featureBuffer.Shape = geometry
featureOID = featureCursor.InsertFeature(featureBuffer);
}
featureCursor.Flush();
3、数据删除delete
//by yllandgis@126.com yanleigis@21cn.com2008.7.7
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();
}
4、数据更新update
//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();
}
原文链接: https://www.cnblogs.com/arxive/p/6114330.html
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