CODEWITHSUNDEEP
c#linq-to-entities
user2740190
user2740190

Reputation:

Conditionally adding one more condition to a LINQ statement

I have something like this:

public Assignments GetAssignmentsForProider(string provider_k, string recordType)
{
    if (recordType == "A")
    {
       var query = from ea in this.Context.Assignments
            where ea.Provider_K == provider_k
                  && ea.Active == true
                  && ea.RecordType == "A"
            select ea;
        return query.FirstOrDefault();
    }
    else if (recordType == "E")
    {
       var query = from ea in this.Context.Assignments
            where ea.Provider_K == provider_k
                  && ea.RecordType == "E"
            select ea;
        return query.FirstOrDefault();
    }
}

Two problems:

  1. It doesn't compile! because it needs a default return statement too and I am not sure what to return really but in my program it will never happen that none of those if conditions happen. I am always in the first one or second one.

  2. Really all they are different in is in first one we check for Active == true and in second one we don't. So is there a better way of writing this too?

Upvotes: 1

Views: 329

Answers (3)

Mashton
Mashton

Reputation: 6415

One way to chain your conditions ...

public Assignments GetAssignmentsForProider(string provider_k, string recordType)
{
    var query = from ea in this.Context.Assignments
                where ea.Provider_K == provider_k
                select ea;

    if (recordType == "A")
    {
       query = from q in query
               where q.Active == true
                  && q.RecordType == "A"
               select q;
    }
    else if (recordType == "E")
    {
       query = from q in query
               where q.RecordType == "E"
               select q;    
    }

    return query;
}

But Bjarke Søgaard has the better method for filtering on record type, because your criteria parameter directly matches on the query data ... so you could just use it directly.

Upvotes: 1

Magnus
Magnus

Reputation: 46909

I would probably write it like this:

public Assignments GetAssignmentsForProider(string provider_k, string recordType)
{
    var query = from ea in this.Context.Assignments
                where ea.Provider_K == provider_k &&
                      ea.RecordType == recordType
                select ea;

    if (recordType == "A")
        return query.Where(ea => ea.Active).FirstOrDefault();
    else if (recordType == "E")
        return query.FirstOrDefault();

    return null;
}

Upvotes: 1

Falgantil
Falgantil

Reputation: 1310

Something like this?

public Assignments GetAssignmentsForProider(string provider_k, string recordType)
{
    var query = from ea in this.Context.Assignments
        where ea.Provider_K == provider_k
                && ea.RecordType == recordType
                && (recordType == "E" ? true : ea.Active)
            select ea;
        return query.FirstOrDefault();
}

This should satisfy your need.

Upvotes: 2

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