Dynamically generating Entity Framework Include based on $expand?

[NetTecture]

This is a documentation request.

I can not wrap my head around this and do not find any relevant documentation.

Depending on the $expand clause, I must generate a set of dynamic .Include clauses for Entity Framework.

Is there any current example on how to analyze the $expand statement as I can get from the ODataQueryOptions?

I manage to get to this:

       var se = queryOptions.SelectExpand;
        foreach (var selectedItem in se.SelectExpandClause.SelectedItems) {
            if (selectedItem.GetType() == typeof(ExpandedNavigationSelectItem)) {
                ExpandedNavigationSelectItem navigationProperty = (ExpandedNavigationSelectItem)selectedItem;

but I am unable to get the last cast working. Examples seem to be outdated. This is the set of includes:

using System.Data.Entity; using System.Linq; using System.Web.OData; using System.Web.OData.Routing; using System.Web.OData.Query;

using Microsoft.Data.OData.Query; using Microsoft.Data.OData.Query.SemanticAst;

Part of the problem may well be that I am using AutoMapper ProjectTo - but this just is needed to hide the entities from the API level and allow efficient querying. Anyone has an example how to get the necessary expand paths (as strings)?

[mtroth-microsoft]

Did you try posting your question on stack overflow? Git hub issues is more likely to get focus in the context of a PR you are submitting to address a problem or add a feature. Questions are generally best circulating through the stack overflow community.

[PabloMR92]

I was in the same spot as you, so I wrote a this as a helper:

private static List<string> GetIncludesFromExpandClause(SelectExpandQueryOption clause)
        {
            var includes = Enumerable.Empty<string>().ToList();

            var includeText = clause != null ? clause.RawExpand : null;
            if (!string.IsNullOrEmpty(includeText))
            {
                foreach (var item in clause.SelectExpandClause.SelectedItems)
                {
                    includes.AddRange(GetExpandedForAutomapper(((ExpandedNavigationSelectItem)item)));
                }
            }

            return includes;
        }

private static List<string> GetExpandedForAutomapper(ExpandedNavigationSelectItem node)
        {
            List<string> automapperGroupIncludes = new List<string>(),
                    automapperSingleIncludes = new List<string>();

            if (node.SelectAndExpand.SelectedItems.Count() > 0)
                foreach (var item in node.SelectAndExpand.SelectedItems)
                {
                    automapperSingleIncludes = GetExpandedForAutomapper((ExpandedNavigationSelectItem)item);
                    foreach (var automapperSingleInclude in automapperSingleIncludes)
                    {
                        automapperGroupIncludes.Add(string.Join(".", new string[] { node.NavigationSource.Name, automapperSingleInclude }));
                    }

                }
            if (automapperGroupIncludes.Count == 0)
                automapperGroupIncludes.Add(node.NavigationSource.Name);

            return automapperGroupIncludes;
        }

Hope it helps!