Issue with Linq query syntax. Cannot convert to list

Question

I am getting an error when trying to convert my linq query to a list like I would normally do.

Here is my query:

var Services = (from sa in _ctx.ServiceAttrs
    join pp in _ctx.ProcessorProducts 
        on new { ServiceId = sa.ServiceID, PrsnPk = ActivePrsnPk } equals
        new { ServiceId = pp.ServiceID, PrsnPk = pp.PrsnPK } into tmp
            from PersonServices in tmp.DefaultIfEmpty()
                .Select(PersonServices => new ReviewerServiceDto()
                {
                    ServiceId = sa.ServiceID,
                    ServiceAliasDescription = sa.ServiceAlias,
                    IsSelected = (PersonServices.IsActivated == null) 
                        ? false
                        : true,
                }).OrderBy(dto => dto.ServiceAliasDescription).ToList();

I am getting redlined right at the ToList(). Tells me parenthesis can be removed, however when I remove them, it will no longer evoke the method to convert to list...

I thought I was missing a bracket somewhere but It looks good to me.

If I see it well, the first bracket does not have a closing pair (or can be remove that). — Tor
– Tor, Commented Jan 22, 2019 at 15:29
Is it redlined (error) or greenlined (warning) ? Post the exact message, including the error/warning number. — Henk Holterman
– Henk Holterman, Commented Jan 22, 2019 at 15:31
Note also that IsSelected = (PersonServices.IsActivated == null) ? false : true is equivalent to simply IsSelected = PersonServices.IsActivated != null. — Olivier Jacot-Descombes
– Olivier Jacot-Descombes, Commented Jan 22, 2019 at 15:32
If you broke the query up into multiple statements, rather than trying to force the whole thing into a single statement, the problem would either go away, or become apparent to you. Trying to force the whole query into a single statement is needlessly complicatin git. — Servy
– Servy, Commented Jan 22, 2019 at 15:41

Olivier Jacot-Descombes · Accepted Answer · 2019-01-22 16:01:55Z

1

Besides a missing bracket, you are mixing LINQ syntax with extension method syntax. In from PersonServices in tmp.DefaultIfEmpty() .Select the select cannot be an extension method call.

This should work

var Services = (
    from sa in _ctx.ServiceAttrs
    join pp in _ctx.ProcessorProducts
        on new { ServiceId = sa.ServiceID, PrsnPk = ActivePrsnPk }
        equals new { ServiceId = pp.ServiceID, PrsnPk = pp.PrsnPK }
        into tmp
    from PersonServices in tmp.DefaultIfEmpty()
    select new ReviewerServiceDto() {
        ServiceId = sa.ServiceID,
        ServiceAliasDescription = sa.ServiceAlias,
        IsSelected = PersonServices.IsActivated != null
    }
)
.OrderBy(dto => dto.ServiceAliasDescription)
.ToList();

A proper indentation helps in distinguishing the LINQ syntax part from the extension method part.

Btw.: the second from would have to be expressed as SelectMany in extension method syntax.

edited Jan 22, 2019 at 16:01

answered Jan 22, 2019 at 15:50

Olivier Jacot-Descombes

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1 Comment

Jacked_Nerd Over a year ago

Beautiful. Thank you.

static_cast · Accepted Answer · 2019-01-22 16:43:20Z

1

First of all, you are opening a bracket without closing it.

You are applying the OrderBy() and the ToList() to: tmp.DefaultIfEmpty().Select(..), if you want to do that on purpose, all you need is to add a select after that and close the bracket).

You need to add a select clause to tell what data you require from the query. This msdn article describes the basic query operation and structure.

  }).OrderBy(dto => dto.ServiceAliasDescription).ToList()   select something);

edited Jan 22, 2019 at 16:43

static_cast

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answered Jan 22, 2019 at 15:43

Martin Bonafede

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2 Comments

Jacked_Nerd Over a year ago

This is true, however if I close it, it will not recognize the sa alias. So I am not sure if there is a different way to structure this or not...

Jacked_Nerd Over a year ago

Also, I am needing to select all of it, not just something. My apologizes, I am a novice at linq. This does solve the issue however, but I really just want to shove it all into a list.

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