public IReadOnlyList<Row> GetRowsRelatedToOriginRows( 
   IEnumerable<long> originObjectIDs
)

public async Task GettingRowsRelatedByRelationshipClass()
{
  await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
  {
    using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
    using (RelationshipClass relationshipClass = geodatabase.OpenDataset<RelationshipClass>("LocalGovernment.GDB.luCodeViolationHasInspections"))
    using (FeatureClass violationsFeatureClass = geodatabase.OpenDataset<FeatureClass>("LocalGovernment.GDB.luCodeViolation"))
    using (Table inspectionTable = geodatabase.OpenDataset<Table>("LocalGovernment.GDB.luCodeInspection"))
    {
      List<Row> jeffersonAveViolations = new List<Row>();
      QueryFilter queryFilter = new QueryFilter { WhereClause = "LOCDESC LIKE '%Jefferson%'" };

      using (RowCursor rowCursor = violationsFeatureClass.Search(queryFilter, false))
      {
        while (rowCursor.MoveNext())
        {
          jeffersonAveViolations.Add(rowCursor.Current);
        }
      }

      IReadOnlyList<Row> relatedOriginRows = null;
      IReadOnlyList<Row> relatedDestinationRows = null;

      try
      {
        QueryFilter filter = new QueryFilter { WhereClause = "ACTION = '1st Notice'" };

        using (Selection selection = inspectionTable.Select(filter, SelectionType.ObjectID, SelectionOption.Normal))
        {
          relatedOriginRows = relationshipClass.GetRowsRelatedToDestinationRows(selection.GetObjectIDs());
        }

        bool containsJeffersonAve = relatedOriginRows.Any(row => Convert.ToString(row["LOCDESC"]).Contains("Jefferson"));

        List<long> jeffersonAveViolationObjectIds = jeffersonAveViolations.Select(row => row.GetObjectID()).ToList();

        relatedDestinationRows = relationshipClass.GetRowsRelatedToOriginRows(jeffersonAveViolationObjectIds);
        bool hasFirstNoticeInspections = relatedDestinationRows.Any(row => Convert.ToString(row["ACTION"]).Contains("1st Notice"));
      }
      finally
      {
        Dispose(jeffersonAveViolations);
        Dispose(relatedOriginRows);
        Dispose(relatedDestinationRows);
      }
    }
  });
}

private static void Dispose(IEnumerable<Row> rows)
{
  foreach (Row row in rows)
    row.Dispose();
}

public async Task DeletingARelationship()
{
  await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
  {
    using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
    using (RelationshipClass relationshipClass = geodatabase.OpenDataset<RelationshipClass>("LocalGovernment.GDB.luCodeViolationHasInspections"))
    using (FeatureClass violationsFeatureClass = geodatabase.OpenDataset<FeatureClass>("LocalGovernment.GDB.luCodeViolation"))
    {
      QueryFilter queryFilter = new QueryFilter { WhereClause = "LOCDESC LIKE '%Jefferson%'" };

      using (RowCursor rowCursor = violationsFeatureClass.Search(queryFilter, false))
      {
        if (!rowCursor.MoveNext())
          return;

        using (Row jeffersonAveViolation = rowCursor.Current)
        {
          IReadOnlyList<Row> relatedDestinationRows = relationshipClass.GetRowsRelatedToOriginRows(new List<long> { jeffersonAveViolation.GetObjectID() });

          try
          {
            EditOperation editOperation = new EditOperation();
            editOperation.Callback(context =>
            {
              foreach (Row relatedDestinationRow in relatedDestinationRows)
              {
                try
                {
                  relationshipClass.DeleteRelationship(jeffersonAveViolation, relatedDestinationRow);
                }
                catch (GeodatabaseRelationshipClassException exception)
                {
                  Console.WriteLine(exception);
                }
              }
            }, relationshipClass);

            bool editResult = editOperation.Execute();
          }
          finally
          {
            foreach (Row row in relatedDestinationRows)
              row.Dispose();
          }
        }
      }
    }
  });
}