Implementing extended criteria for some predefined schematic rules
PlantOnCableDiameter.cs
// Copyright 2012 ESRI
// 
// All rights reserved under the copyright laws of the United States
// and applicable international laws, treaties, and conventions.
// 
// You may freely redistribute and use this sample code, with or
// without modification, provided you include the original copyright
// notice and use restrictions.
// 
// See the use restrictions.
// 

namespace CustomExtCriteriaCS
{
  [System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)]
  [System.Runtime.InteropServices.Guid(PlantOnCableDiameter.GUID)]
  [System.Runtime.InteropServices.ProgId(PlantOnCableDiameter.PROGID)]
  public class PlantOnCableDiameter : ESRI.ArcGIS.Schematic.ISchematicNodeReductionExtended
  {
    public const string GUID = "28231119-7E86-4924-AC04-F5AE21858112";
    public const string PROGID = "CustomExtCriteriaCS.PlantOnCableDiameter";

    #region Component Category Registration
    [System.Runtime.InteropServices.ComRegisterFunction()]
    public static void Register(string regKey)
    {
      ESRI.ArcGIS.ADF.CATIDs.SchematicRulesExtendedCriteria.Register(regKey);
    }

    [System.Runtime.InteropServices.ComUnregisterFunction()]
    public static void Unregister(string regKey)
    {
      ESRI.ArcGIS.ADF.CATIDs.SchematicRulesExtendedCriteria.Unregister(regKey);
    }
    #endregion

    #region SchematicNodeReductionExtended Implementations
    //  Description of the new schematic node reduction criteria
    public string Name
    {
      get
      {
        return "Reduce if connected cable diameters are 8 (C#)";
      }
    }

    public bool SelectReduction(ESRI.ArcGIS.Schematic.ISchematicInMemoryFeatureNode node, ESRI.ArcGIS.Schematic.IEnumSchematicInMemoryFeature enumLink, ref ESRI.ArcGIS.Schematic.ISchematicInMemoryFeatureLink link)
    {
      // if enumLink is empty do nothing
      if (enumLink == null) return false;
      if (enumLink.Count == 0) return false;

      enumLink.Reset();

      ESRI.ArcGIS.Schematic.ISchematicInMemoryFeature schemAssociatedLink;
      schemAssociatedLink = enumLink.Next();

      // for each link in enumLink
      while (schemAssociatedLink != null)
      {
        // get cables
        ESRI.ArcGIS.Geodatabase.IFeature cablesFeature;
        cablesFeature = schemAssociatedLink.SchematicElement as ESRI.ArcGIS.Geodatabase.IFeature;

        if (cablesFeature == null) return false;

        // get cables class
        ESRI.ArcGIS.Geodatabase.IDataset cablesDataset;
        cablesDataset = (ESRI.ArcGIS.Geodatabase.IDataset)cablesFeature.Class;

        // if not the right class do nothing
        if (cablesDataset.Name.IndexOf("cables") == 0) return false;

        // get workspace
        ESRI.ArcGIS.Geodatabase.IFeatureWorkspace cablesWorkspace;
        cablesWorkspace = (ESRI.ArcGIS.Geodatabase.IFeatureWorkspace)cablesDataset.Workspace;

        // open table cables_attributes
        ESRI.ArcGIS.Geodatabase.ITable cablesTable;
        cablesTable = cablesWorkspace.OpenTable("cables_attributes");
        if (cablesTable == null) return false;

        // get diameter value
        object cableDiameter = cablesTable.GetRow(cablesFeature.OID).get_Value(1);

        if (cableDiameter.ToString() != "8") return false; //if not 8 do nothing

        schemAssociatedLink = enumLink.Next();
      }
      return true; // if this far
    }
    #endregion
  }
}