Chaining / building LINQ query with an OR instead of AND

Question

Edited to be clearer.

If for example I have this IQueryable:

DateTime theDate = new DateTime(2015, 09, 30);

var query = from org in Organisations
            where org.DisableOrganisation == false &&
              org.DisableReports == false
            select new
            {
                OrganisationId = org.OrganisationId
            };

and later in the method I want to add an OR to it, e.g.

// Check to see if the date is the last day of the month.
if (theDate.AddDays(1).Day == 1)
{
    // The following statement introduces an AND but I want to make this an OR.
    query = query.Where(x => x.Frequency == "M");
}

This effectively makes my query...

var query = from org in Organisations
            where org.DisableOrganisation == false &&
              org.DisableReports == false &&
              org.Frequency == "M"
            select new
            {
                OrganisationId = org.OrganisationId
            };

but I want to make it...

var query = from org in Organisations
            where (org.DisableOrganisation == false &&
              org.DisableReports == false) ||
              org.Frequency == "M"
            select new
            {
                OrganisationId = org.OrganisationId
            };

How do I go about making this an OR instead of an AND ?

P.S. Cannot use PredicateBuilder as it is essentially LinqKit which has a dependency of EntityFramework (≥ 6.0.2), I'm stuck using EF 4.3.1

SOLVED: Thanks to D Stanley (To be honest I had used this form of solution before, I simply forgot about it).

DateTime theDate = new DateTime(2015, 09, 30);
bool isEndOfMonth = theDate.AddDays(1).Day == 1;

var query = from org in Organisations
            where (org.DisableOrganisation == false &&
              org.DisableReports == false) ||
              (isEndOfMonth &&
               pr.ProfileType == "L" && 
               pr.Frequency == "M")
            select new
            {
                OrganisationId = org.OrganisationId
            };

possible duplicate of [LINQ WHERE with OR](http://stackoverflow.com/questions/4136116/linq-where-with-or) — TomDoesCode, Sep 30 '15 at 12:33
@TomDoesCode It in essence duplicates that question, but that question is 4 years old... is there a newer solution? — Paul Zahra, Sep 30 '15 at 12:35
@TomDoesCode The possible duplicate points to LinqKit... which has a dependency of EntityFramework (≥ 6.0.2), I'm using EF 4.3.1 — Paul Zahra, Sep 30 '15 at 12:38

score 2 · Answer 1 · answered Sep 30 '15 at 12:38

2

To combine conditions with OR instead of AND, use the PredicateBuilder:

predicate = predicate.Or(p => p.Description.Contains (temp));
return dataContext.Products.Where(predicate);

answered Sep 30 '15 at 12:38

Ilya Chumakov

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LinqKit... which has a dependency of EntityFramework (≥ 6.0.2), I'm using EF 4.3.1 – Paul Zahra Sep 30 '15 at 12:39
source code is open, maybe it is possible to extract functionality you need. https://github.com/scottksmith95/LINQKit – Ilya Chumakov Sep 30 '15 at 12:43

D Stanley · Accepted Answer · 2015-09-30T12:40:19.180

You can't do it by chaining - you'll have to use some sort of expression builder, or just build that in your original filter:

var day = theDate.AddDays(1).Day;

var query = from org in Organisations
            where (org.DisableOrganisation == false &&
                   org.DisableReports == false) ||
                  (day == 1 &&
                   org.ProfileType == "L" && 
                   org.Frequency == "M")
            select new
            {
                OrganisationId = org.OrganisationId
            };

Chaining / building LINQ query with an OR instead of AND

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