Cannot implicitly convert type 'bool?' to 'bool' in a LinQ query?

Question

My where statement fails obviously, but all I can find are samples on how to convert it outside of a LinQ query. The closest I can come is:

&& rdoNoPhone.Checked ? d.PHONE!= null : true

But, I am not quite sure how that works in my case. I understand the my SQL field called Active allows 3 values, trues, false and null and I am guessing that my answer is all in that little question mark.

LinQtoSQLDataContext db = new LinQtoSQLDataContext();
                   var query = from a in db.Admins
                               where a.Active = true
                               orderby a.Name
                               select new { a.Name, a.LoginName};

I should also ask how it is possible to use an SQL IN statement in a LinQ query. For example, changing the following into LinQ:

Select Field1, Field2, Level
From Table
Where Level IN (1,2,5)

Both questions have been answered before. You're looking for `nullableBool.HasValue && nullableBool.Value == true` and for your second question `new[] {1, 2, 5}.Contains(value)`. — CodeCaster, Nov 13 '14 at 16:15
That worked: nullableBool.HasValue && nullableBool.Value == true — Lore, Nov 13 '14 at 17:04
possible duplicate of [checking if a nullable bool is null or not](http://stackoverflow.com/questions/13304676/checking-if-a-nullable-bool-is-null-or-not) — Dour High Arch, Nov 13 '14 at 17:12

score 4 · Accepted Answer · answered Nov 13 '14 at 17:09

I believe your equal sign in the line where a.Active = true should actually be two equal signs (to mean a comparison rather than an assignment). In fact, because you're comparing a bool to true, you don't even need a comparison operator. You can just write a.Active.Value.

LinQtoSQLDataContext db = new LinQtoSQLDataContext();
                   var query = from a in db.Admins
                               where a.Active.HasValue && a.Active.Value
                               orderby a.Name
                               select new { a.Name, a.LoginName};

For your second question, you can use Contains(value) to address this. For example:

int[] Levels = new int[] { 1, 2, 5 };
int Level = 2;
if (Levels.Contains(Level))
{
    // Level was found in Levels
}

Cannot implicitly convert type 'bool?' to 'bool' in a LinQ query?

1 Answers1