vb.net - Converting VB Linq to C# -

i'm in process of teaching myself c# converting existing project , stuck converting following vb linq code:

dim outstuff = tt in (from t in products.selectmany(function(p) if(p.tags isnot nothing, p.tags, new observablecollection(of tagmodel)))                group tagname = t.name,                                   v = (aggregate p in products if(p.tags isnot nothing, p.tags.contains(t), nothing) sum(p.views)),                                   nl = (aggregate p in products if(p.tags isnot nothing, p.tags.contains(t), nothing) sum(p.num_likes))                g = group, count())                group name = tt.tagname count = sum(tt.count), viewstotal = sum(tt.v), num_likestotal = sum(tt.nl)                select name, count, viewstotal, num_likestotal 

where products observablecollection(of productmodel)

i've mananged convert far:

var x =  products.selectmany(p => (p.tags != null) ? p.tags : new observablecollection<tagmodel>()); var tags = t in x group t t.name g select new { tagname=g.first().name}; 

the 'group by's has me stumped. great...

your query little convoluted , hard follow, let me try describe think looking for. have list of products, each of may have 1 or more tags; , want list of of tags, count of how many products have tag, total number of views of products tag, , total number of "likes" of product tag. if case, following should trick:

// may want add toarray() here filter not executed multiple times during subsequent query var productswithtags = products.where(p => p.tags != null); var outstuff = t in (from p in productswithtags                t in p.tags                select t).distinct()                let matchingproducts = productswithtags.where(p => p.tags.contains(t))                select new { name = t.name,                             count = matchingproducts.count(),                             viewstotal = matchingproducts.sum(p => p.views),                               num_likestotal = matchingproducts.sum(p => p.num_likes)                           };