FirstOrDefault inline null checking

LINQ and Entity Framework are used to check for null values in C# variables.

In your example, ...entry... will ...never... be ...null.... What you think of as ...null... is in fact an ...IEnumerable<Entry>... with no items....If you want to check if there is at least one entry with your criteria, you normally do something like:...var entries = myDB.Entries.Where(e => e.Email == entry.Email); if (entries.Any()) { // ... ...

In Entity Framework, check for null values in Linq queries.

You can only compare an ...int... to ...NULL... if the ...int... is ...nullable.... If not, the default value for ...int... will be ...0... and never ...null.......You define a nullable int property like this:...int? value { get; set; } ...And check it like this:...if ( value != null ) { int x = value.Value; } ...In the where clause of a Linq qu...

LINQ check if FirstOrDefault is null and use it

Just call ....Any(a => a.DateReturned == null)... to check whether there are any items that meet the condition....If you only want to check the latest assignment, add ....Take(1)... before the ....Any()....

How to check model string property for null in a razor view

I am working on an ...ASP.NET MVC 4... application. I use ...EF 5... with code first and in one of my entities I have :...public string ImageName { get; set; } public string ImageGUIDName { get; set; } ...those two properties which are part of my entity. Since I may not have image uploaded these values can be null but when I render the view passing...

OrderBy().FirstOrDefault(<condition>) vs. Where(<condition>).OrderBy().FirstOrDefault()

Not sure if that's the root cause of the problem, but there is a subtle difference between those two queries - the relative position of OrderBy and Where. In relational world, filter invalidates sorting done in the subquery. EF tries to compensate for this discrepancy by "lifiting" some of the orderbys after the filter, and perhaps is unable to lif...

How to handle NULL object property with FirstOrDefault using Linq

You need not to use ...Where... and the ...FirstOrDefault... in this case, you can specify the filter condition inside the ...FirstOrDefault... itself. But which will give you null if there are no records satisfying the condition(because in the absence of first value it will give you the default value, for reference type objects the default value i...

Effort- FirstOrDefault returns null when Faking Database

I'm trying to create some unit tests for my project, after much digging around I found Effort, the idea is great, it mocks the database instead of the dealing with faking the DBContext which by the way is really hard to get it right when using a complex schema....However I'm trying to get the Email of a user after I specifically added it to the in-...

How to fix FirstOrDefault returning Null in Linq

You're problem is because your DefaultIfEmpty is executed AsQueryable. Perform it ...AsEnumerable... and it will work:...// create the default element only once! static readonly ClinicalAssPatInVcm defaultElement = new ClinicalAssPatInVcm (); var result = <my big linq query> .Where(x => x.ClinicalAssetID == id) .AsEnumerable() .Default...

Check for null entities in EF statement

I have a statement like this:...AssignedCas AssignedCase in caseList.GroupBy(o => o.CaseBatch.CaseBatchName) .Select(g => g.First()).ToList() ...But at time ...o.CaseBatch.CaseBatchName... can be ...null..., in which case the above statement will not execute....Is there a way in the above statement to check if ..

Why EF6 LINQ does not generate proper "is null" SQL for null string variable comparison?

We have an EDMX-based EF6 application, where we'd like to run a LINQ query like this....string category = ... // comes from somewhere and equals to null context.Product.Where(e => e.Category == category).ToArray(); ...The problem I see is that the generated SQL contains a ...[table].[Category] = @p...... in the where clause, regardless of the varia...