Using OsmSharp i wrote some code but it seems to not working as i expected :( But i dont know why :(

The funniest part is that there are some relations that eg.

<waynode> <city/> <name>Otto-Reutter-Straße</name> <type>residential</type> <areas> <arearelation> <nodeid>430112483</nodeid> <name>Dotzheim</name> <type>boundary</type> <boundary>administrative</boundary> <adminlevel>9</adminlevel> </arearelation> <arearelation> <nodeid>430112483</nodeid> <name>Schierstein</name> <type>boundary</type> <boundary>administrative</boundary> <adminlevel>9</adminlevel> </arearelation> </areas> </waynode>

but i most cases (output xml contains 16.868.559 lines of text) Ways(count 3.369.198) are not connected in Relation(count 2.818) whole file contain: Nodes: 331.798.468 Ways: 54.132.981 Relations: 666.231 and i dont use Node's at all at current implementation.

using (var fileStream = File.OpenRead(@".\germany-latest.osm.pbf"))
        {
            // create source stream.
            var source = new PBFOsmStreamSource(fileStream);

            var relationNodes = source
                .Where(w => 
                    w.Type == OsmGeoType.Relation
                    && w.Tags.ContainsKey("boundary")
                    && w.Tags.ContainsKey("admin_level"))
                .SelectMany(s => (s as Relation)?.Members
                            .Where(wm => wm.Type == OsmGeoType.Way)
                            .Select(sm => new AreaRelation()
                            {
                                NodeId = sm.Id,
                                Name = s.Tags.GetValue("name"),
                                Type = s.Tags.GetValue("type"),
                                Boundary = s.Tags.GetValue("boundary"),
                                AdminLevel = s.Tags.GetValue("admin_level")
                            })
                            .OrderBy(o => o.AdminLevel))
                .ToList();

            var relationNodesGroupedByNodeId = relationNodes.GroupBy(k => k.NodeId, v => v).ToDictionary(k => k.Key, v => v);

            var wayNodes = source
                .Where(w =>
                    w.Type == OsmGeoType.Way
                    && w.Tags.ContainsKey("highway")
                    && w.Tags.ContainsKey("name"))
                .Select(s =>
                    new WayNode()
                    {
                        City = s.Tags.GetValue("is_in:city"),
                        Name = s.Tags.GetValue("name"),
                        Type = s.Tags.GetValue("highway"),
                        Areas = (s.Id.HasValue && relationNodesGroupedByNodeId.ContainsKey(s.Id.Value)) 
                            ? relationNodesGroupedByNodeId[s.Id.Value].ToList() 
                            : null
                    })
                .Distinct().ToList();

            XmlSerializer x = new XmlSerializer(wayNodes.GetType());

            var path = @".\GermanyWays2.xml";
            FileStream file = System.IO.File.Create(path);

            x.Serialize(file, wayNodes);
            file.Close();
}

What are you actually trying to accomplish?

I have to extract all streets for Germany with their administration bouderies. So if street is in Berlin i have to get street name and collection of areas e.g. level 2: Germany level 4: Berlin level 9: Mitte level 10: Moabit (i took areas names and leves from www.osm-boundaries.com)