ArcObjects Library Reference (NetworkAnalyst)

NAClassDefinition CoClass

Defines how fields should be mapped as inputs and outputs of analysis functions.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server. Requires Network Analyst Extension.

Interfaces

Interfaces	Description
IClone (esriSystem)	Provides access to members that control cloning of objects.
INAClassDefinition	Provides access to properties common to all network analyst class definitions.
INAClassDefinition2	Provides access to properties common to all network analyst class definitions.
INAClassDefinitionEdit	Provides access to editable properties common to all network analyst class definitions.
IPersistStream (esriSystem)
IXMLSerialize (esriSystem)	Provides access to members that XML serialize and deserialize an object to/from XML.

Remarks

The NAClassDefinition is created and maintained by the network solver. The NAClassDefinition holds information about how the NAClass fields should be created when the solver creates the NAContext and corresponding NAClass objects. It also holds additional information about the fields of the NAClass that cannot be found on the IField interface. This information is used by the solver and the Network Analyst Tools.

There are three ways to obtain NAClassDefinition objects:

A NAClassDefinition object can also be obtained from the NAClass object via the INAClass.ClassDefinition property. The NAClass objects are obtained from a NAContext object via the INAContext.NAClasses property. In this case, the class definitions are associated with a NAContext's NAClass, and therefore have some properties populated that wouldn't be otherwise. In C#:
            INASolver naSolver = new NARouteSolverClass();

            INAContext naContext = naSolver.CreateContext(deNetworkDataset, "My Context");

            INamedSet naClasses = naContext.NAClasses;

            INAClass naClass = naClasses.get_ItemByName("Stops") as INAClass;

            INAClassDefinition naClassDefinition = naClass.ClassDefinition;
A set of NAClassDefinitions can be obtained from a NASolver object, via the INASolver.ClassDefinitions property. In this case, the class definitions are a kind of template or default that is not associated with a live NAClass involved in analysis. Some properties, like CandidateFieldNames and the network dataset specific Fields, will not be populated. In C#:
            INASolver naSolver= new NARouteSolverClass();

            INamedSet naClassDefinitions = naSolver.ClassDefinitions;

            INAClassDefinition naClassDefinition = naClassDefinitions.get_ItemByName("Stops") as INAClassDefinition;
The NAClassDefinition object can be CoCreated manually. In this case, the properties will be empty. This might be done, for example, to create your own class definitions for use with a custom solver. In C#:
INAClassDefinition naClassDef = new NAClassDefinitionClass ();