Develop Reference

Select JOIN table using Linq and QueryExpression

I have this:
QueryExpression query = new QueryExpression("entity1");
query.ColumnSet = new ColumnSet(true);
LinkEntity accountLink = query.AddLink("entity2", "entity1id", "entity1id", JoinOperator.Inner);
accountLink.Columns = new ColumnSet(true);
accountLink.EntityAlias = "e2";
...
EntityCollection entities = service.RetreiveMultiple(query);
Lets say there is more joins and conditions in the query, but for us is important just this JOIN.
Now I want to get IEnumerable<Entity> with entity2 instances from query. How can I do it? I'm thinking about using Linq, but I dont know how excatly write the command. I want something like this:
IEnumerable<Entity> entities2 = from entity in entities.Entities
?? e2 ???
select ??;

Here's an example D365 LINQ query including joins with late bound entities:
public JsonResult Offices()
{
var connectionString = #"SET YOUR CONNECTION STRING";
var svc = new CrmServiceClient(connectionString);
var list = new List<KeyValuePair<Guid, string>>();
using (var context = new Microsoft.Xrm.Sdk.Client.OrganizationServiceContext(svc))
{
var result = (from a in context.CreateQuery("account")
join o in context.CreateQuery("opportunity")
on a.GetAttributeValue<Guid>("accountid") equals o.GetAttributeValue<Guid>("new_igoffice")
where a.GetAttributeValue<OptionSetValue>("statecode").Value == 0
where o.GetAttributeValue<Guid>("parentaccountid") != Guid.Empty
orderby a.GetAttributeValue<string>("name")
select new KeyValuePair<Guid, string>(a.GetAttributeValue<Guid>("accountid"), a.GetAttributeValue<string>("name")))
.Distinct();
list.AddRange(result);
}
return Json(list, JsonRequestBehavior.AllowGet);
}

How do I find all collections with a certain string in the name in my MongoDB database?

I've got a database containing several collections. Some has got a name like "carpenter_title_year_version". Others has got a name like "plumber_title_year_version". How do I set up a filter to retrieve all collections where the string "carpenter" is in the collectionname?
I'm thinking something like:
var filterBuilder = Builders<GroupEntity>.Filter;
var projectionBuilder = Builders<GroupEntity>.Projection;
var collection = Database.GetCollection<GroupEntity>("dbname");
var filter = filterBuilder.ElemMatch("carpenter..., ?"); //<--- ???
var projection = projectionBuilder.Exclude("_id");
var list = await collection.Find(filter).Project(projection).ToListAsync();

There's (and an async version of it)
IAsyncCursor<MongoDB.Bson.BsonDocument> IMongoDatabase.ListCollections(ListCollectionsOptions options = null, CancellationToken cancellationToken = null);
You can use the filter from the collection options to match the collection name.
// <CAPS INSIDE> are wildcards
var _client = new MongoClient(#"connection string");
var _database = _client.GetDatabase("<DATABASE NAME>");
var bre = new BsonRegularExpression("<YOUR REGEX PATTERN>");
var copt = new ListCollectionsOptions{ Filter =
Builders<BsonDocument>.Filter.Regex ("name", bre )
};
var collectionsWithMatchingNames = _database.ListCollections(copt).ToList().Select (col => col["name"]);
Only then you get your particular collection, like:
foreach (var x in collectionsWithMatchingNames)
var collection = _database.GetCollection<BsonDocument>(x);

Mongo DB $near query in c#?

var query ="{'Geo':{'$near': {'$geometry': {'type': 'Point' ,'coordinates':[]} }}}";
var parsing = BsonDocument.Parse(query);
var qwithcoor = parsing["Geo"]["$near"]["$geometry"]["coordinates"].AsBsonArray;
qwithcoor.AddRange(coordinates);
parsing["Geo"]["$near"].AsBsonDocument.Add("$maxDistance", radius);
var collection = database.GetCollection<BsonDocument>("mycollection");
var documents = await collection.Find(parsing).ToListAsync();
I want to do this with Builders<BsonDocument>.Filter. Like this:
var query=Builders<BsonDocument>.Filter.Near();
var documents=await collection.Find(query).ToListAsync();
do I use Near after the Filter? What are the Near parameters?

I solve this with
var gp =new GeoJsonPoint<GeoJson2DGeographicCoordinates>(new GeoJson2DGeographicCoordinates(coordinates[0], coordinates[1]));
var query=Builders<BsonDocument>.Filter.Near("Geo",gp,radius);
var result = await col.Find(query).ToListAsync();

How to get result of rollup query for a custom entity

When trying to get the records I get this error
The 'Rollup' method does not support entities of type 'new_X'.
This is my code
RollupRequest req = new RollupRequest();
QueryExpression qe = new QueryExpression();
qe.EntityName = "new_x";
qe.ColumnSet = new ColumnSet(true);
req.Query = qe;
req.Target = new EntityReference("new_newpost", new Guid("xxxxxxxxxxxxxxxxxxxxxxxxxxxxx"));
req.RollupType = RollupType.Related;
RollupResponse resp = (RollupResponse)xrm.Execute(req);
How can I get the results of rollup query
Thanks in advance
For custom entities you can do the fallowing
var rollupQuery = xrm.GoalRollupQuerySet.Where(c => c.Id == x.new_RecordstoRun.Id).First();
var result = xrm.RetrieveMultiple(new FetchExpression(rollupQuery.FetchXml));
But - How can I add a 'Skip' or 'Take' Linq to this?

You can only use the RollupRequest on a certain set of entities described on the MSDN.
So this will never work for "new_x" or "new_newpost".
This article has a correct demonstration of the RollupRequest using opportunity and account.
I would suggest just creating your own custom QueryExpression to retrieve all "new_x" and then link to "new_newpost" with LinkEntities.

Here is my code so get the results of RollupQuery
List<Guid> GetAllResultsFromRollupQuery(XrmServiceContext xrm, Guid rollupQueryId)
{
var rollupQuery = xrm.GoalRollupQuerySet.Where(v => v.Id == rollupQueryId).First();
var qa = GetQueryExpression(xrm, rollupQuery.FetchXml);
qa.PageInfo.Count = 1000;
qa.ColumnSet.AddColumn(rollupQuery.QueryEntityType + "id");
var result = new List<Guid>();
EntityCollection ec = null;
do
{
ec = xrm.RetrieveMultiple(qa);
ec.Entities.ToList().ForEach(v => result.Add((Guid)v.Attributes[rollupQuery.QueryEntityType + "id"]));
qa.PageInfo.PageNumber += 1;
} while (ec.MoreRecords == true);
return result;
}
QueryExpression GetQueryExpression(XrmServiceContext xrm, string fetchXml)
{
var req = new FetchXmlToQueryExpressionRequest { FetchXml = fetchXml };
var result = (FetchXmlToQueryExpressionResponse)xrm.Execute(req);
return result.Query;
}

Select all rows but only specific columns

Whats the linq+lambada expression to select all records in a table but only specific columns.
I tried something like the following which didnt work:
var Dc = new MyDataContext();
var mydata = Dc.TableA;
var newdata = mydata.Select(d => d (new {d.columnA,d.columnB,d.columnC}));

You were close - you have to project to an anonymous types with the columns you want:
var mydata = Dc.TableA.Select(d => new {d.columnA,d.columnB,d.columnC});

I think the issue you've got is a minor error in your code (in the example at least)
var Dc = new MyDataContext();
var mydata = Dc.TableA;
var newdata = mydata.Select(d => new {d.columnA,d.columnB,d.columnC});

var Dc = new MyDataContext();
var newdata = Dc.TableA.Select(d => new {d.columnA,d.columnB,d.columnC});