LINQ and ArcObjects

Wed, 12 Sep 2012 15:20:00 +0200

Motivation

LINQ (language integrated query) is a component of the Microsoft. NET Framework since version 3.5. It allows a SQL-like query to various data sources such as SQL, XML etc.

Like SQL also LINQ to SQL provides a declarative notation of problem solving – i.e. you don’t need describe in detail how a task could be solved, you describe what to be solved at all. This frees the developer from error-prone iterator constructs.

F# and ArcObjects, Part 2

Thu, 25 Mar 2010 14:49:00 +0100

After accessing one feature now i iterate through all features of a feature class:

open System;;

#I "C:\Program Files\ArcGIS\DotNet";;
#r "ESRI.ArcGIS.System.dll";;
#r "ESRI.ArcGIS.DataSourcesGDB.dll";;
#r "ESRI.ArcGIS.Geodatabase.dll";;
open ESRI.ArcGIS.esriSystem;;
open ESRI.ArcGIS.DataSourcesGDB;;
open ESRI.ArcGIS.Geodatabase;;

let aoInitialize = new AoInitializeClass();;

let status = aoInitialize.Initialize(esriLicenseProductCode.esriLicenseProductCodeArcEditor);;

let workspacefactory = new SdeWorkspaceFactoryClass();;

let connection = "SERVER=okul;DATABASE=p;VERSION=sde.default;INSTANCE=sde:sqlserver:okul;USER=s;PASSWORD=g";;

let workspace = workspacefactory.OpenFromString(connection, 0);;

let featureWorkspace = (box workspace) :?> IFeatureWorkspace;;

let featureClass = featureWorkspace.OpenFeatureClass("Praxair.SFG.BP_L_ROHR");;

let queryFilter = new QueryFilterClass();;

let featureCursor = featureClass.Search(queryFilter, true);;

let featureCursorSeq (featureCursor : IFeatureCursor) = 
 let actualFeature = ref (featureCursor.NextFeature())
 seq {
 while (!actualFeature) <> null do
 yield actualFeature
 do actualFeature := featureCursor.NextFeature()
 };;


featureCursorSeq featureCursor
 |> Seq.iter (fun feature -> Console.WriteLine ((!feature).OID));;

IFeatureCursor on Marko Apfel

LINQ and ArcObjects

Motivation

F# and ArcObjects, Part 2