Changes between Initial Version and Version 1 of CodeSnippets/GetStaticExtents

Timestamp:

Oct 15, 2008, 10:02:02 AM (16 years ago)

Author:

jbirch

Comment:

--

CodeSnippets/GetStaticExtents

@@ +1 @@
+[[PageOutline]]
+
+This page is an FDO Code Snippet.  Visit the CodeSnippets page to view more!
+
+= Calculating Static Extents =
+
+Some providers require that you perform a !SelectAggregates on a dataset to determine its extents, specifiying the !SpatialExtents function as one of the properties to calculate.
+
+== C++ Example ==
+
+{{{
+#!cpp
+
+  FdoPtr<FdoISelectAggregates> agg = (FdoISelectAggregates*)con->CreateCommand(FdoCommandType_SelectAggregates);
+  agg->SetFeatureClassName(L"MyFeatureClass");
+  FdoPtr<FdoIdentifierCollection> props = agg->GetPropertyNames();
+
+  FdoPtr<FdoExpression> exp = FdoExpression::Parse(L"SpatialExtents(GEOMETRY)");
+  FdoPtr<FdoComputedIdentifier> se = FdoComputedIdentifier::Create(L"Extents", exp);
+  props->Add(se);
+
+  FdoPtr<FdoIDataReader> extrdr = agg->Execute();
+  extrdr->ReadNext();
+
+  FdoPtr<FdoByteArray> ba = extrdr->GetGeometry(L"Extents");
+  //ba contains the extents polygon, in FGF array form, use FdoIGeometry APIs to get the numbers out of it.
+
+}}}
+
+== C# Example ==
+
+{{{
+#!cpp
+
+  public IPolygon GetExtents()
+  {
+    IPolygon retpolygon;
+    ISelectAggregates pselagree = (ISelectAggregates)FDOConnection.CreateCommand(CommandType.CommandType_SelectAggregates);
+ 
+    pselagree.SetFeatureClassName(System.IO.Path.GetFileNameWithoutExtension(OpenedFile));
+    IFeatureReader FDOReader = pselagree.Execute();
+    FgfGeometryFactory GeoFac = new FgfGeometryFactory();
+
+    Byte[] Tmppts = FDOReader.GetGeometry("Geometry");
+
+    IGeometry Geo = GeoFac.CreateGeometryFromFgf(Tmppts);
+
+    retpolygon = (IPolygon)Geo;
+
+    return retpolygon;
+
+  }
+
+}}}
+
+
+== Contributors ==
+
+ * Traian Stanev
+ * Shaik Esu
+