The following code example creates a MemoryRelationshipClass between the us_states featureclass and the us_counties featureclass. It then uses the MemoryRelationshipClass to print the counties that appear in the state of California.

[Visual Basic 6.0]
Private Sub MemRelClassExample(pUS_StatesCl As IObjectClass, pUS_CountyCl As IObjectClass)

  ' ++ Create a MemoryRelationshipClass between states and counties
  Dim pRelationshipClass As IRelationshipClass
  Dim pMemRelationshipClassFact As IMemoryRelationshipClassFactory
  Set pMemRelationshipClassFact = New MemoryRelationshipClassFactory
  Set pRelationshipClass = pMemRelationshipClassFact.Open("test", pUS_StatesCl, _
  "state_fips", pUS_CountyCl, "state_fips", "forward", "backward", esriRelCardinalityOneToMany)

  ' ++ Apply a filter to limit the return to just counties in California
  Dim pQFilter As IQueryFilter
  Set pQFilter = New QueryFilter
  pQFilter.WhereClause = """STATE_NAME"" = 'California'"
  Dim pFeatureClass As IFeatureClass
  Dim pFCursor As IFeatureCursor
  Dim pFeature As IFeature
  Set pFeatureClass = pUS_StatesCl
  Set pFCursor = pFeatureClass.Search(pQFilter, True)
  Set pFeature = pFCursor.NextFeature

  ' ++ List the counties that relate to California
  Dim pRelateSet As ISet
  Dim pRowBuff As IRowBuffer
  Set pRelateSet = pRelationshipClass.GetObjectsRelatedToObject(pFeature)
  Set pRowBuff = pRelateSet.Next
  Do While Not pRowBuff Is Nothing
    Debug.Print pRowBuff.Value(2)
    Set pRowBuff = pRelateSet.Next
  Loop
End Sub

[C#]
    //MemoryRelationshipClass Example
    //The following function creates a MemoryRelationshipClass between the us_states 
    //featureclass and the us_counties featureclass. It then uses the MemoryRelationshipClass
    //to print the counties that appear in the state of California.
    public void MemoryRelationshipClass_Example(IObjectClass usStatesClass, IObjectClass usCountyClass)
    {
        //create a MemoryRelationshipClass between states and counties
        IMemoryRelationshipClassFactory memoryRelClassFactory = new MemoryRelationshipClassFactoryClass();
        IRelationshipClass relationshipClass = memoryRelClassFactory.Open("test", usStatesClass, "state_fips",
            usCountyClass, "state_fips", "forward", "backward", esriRelCardinality.esriRelCardinalityOneToMany);
        //apply a filter to limit the return to just counties in California
        IQueryFilter queryFilter = new QueryFilterClass();
        queryFilter.WhereClause = "STATE_NAME = 'California'";
        //cast for IFeatureClass
        IFeatureClass featureClass = (IFeatureClass)usStatesClass;
        //open a cursor with the filter, recycling can be used because no updates will be made.
        IFeatureCursor featureCursor = featureClass.Search(queryFilter, true);
        IFeature feature = featureCursor.NextFeature();
        
        //list the counties that relate to California
        ESRI.ArcGIS.esriSystem.ISet relateSet = relationshipClass.GetObjectsRelatedToObject((IObject)feature);
        IRowBuffer rowBuffer = (IRowBuffer)relateSet.Next();
        int fieldIndex = rowBuffer.Fields.FindFieldByAliasName("County Name");
        while (rowBuffer != null)
        {
            Console.WriteLine("The county {0} is in California", rowBuffer.get_Value(fieldIndex));
            rowBuffer = (IRowBuffer)relateSet.Next();
        }
    }

[Visual Basic .NET, C++]
No example is available for Visual Basic .NET or C++. To view a Visual Basic 6.0 or C# example, click the Language Filter button in the upper-left corner of the page.