Linq Containsfunction problem

I use Ria Service domainservice for data query.

In My database, there is a table People with firstname, lastname. Then I use EF/RIA services for data processing.

Then I create a Filter ViewModel to capture user inputs, based it the input, I construct a linq Query to access data.

At server side, the default DomainService query for person is:

 public IQueryable<Person> GetPerson()
   {
     return this.Context.Person;
   }

At client side, the linq Query for filter is something like(I use Contains function here):

if (!String.IsNullOrEmpty(this.LastName))
    q = q.Where(p => (p.LastName.Contains(this.LastName)));

The generated linq query is something like(when debugging,I got it):

MyData.Person[].Where(p => (p.LastName.Contains(value(MyViewModel.PersonFilterVM).LastName) || p.Person.LegalLastName.Contains(value(MyViewModel.PersonFilterVM).LastName)))

When I run the app, I put "Smith" for last name for sear开发者_如何学运维ch, but the result is totally irrelevant with "Smith"!

How to fix it?

I'm guessing here as to what your error is so this might not work for you.

In your 2nd code snippet you do the following.

q = q.Where(p => (p.LastName.Contains(this.LastName)));

This is where I think your error is. Linq does not evaluate the where clause until you iterate over it. Try changing the line to the following.

qWithData = q.Where(p => (p.LastName.Contains(this.LastName))).ToList();

The .ToList() call will load the query with data.

When you check in the debugger, does value(MyViewModel.PersonFilterVM).LastName evaluate to Smith at the time the query is resolved?

Recall that queries are not resolved until they are enumerated.