Support LINQ Where/First operators in GridifyMapper

[uxohotteixo]

Hi @alirezanet!

In addition to using .Select and .SelecyMany for nested collections (which works really fine) I've tried the following expressions:

First:

var query = new QueryBuilder<Entity>()
                  .UseEmptyMapper()
                  .AddMap("model", t => t.SubCollection.Where(sc => sc.Prop == "1").Select(s => s.Entity2.Name))
                  .AddCondition("model=someFilterValue")
                  .BuildFilteringExpression();

Second:

var query = new QueryBuilder<Entity>()
                  .UseEmptyMapper()
                  .AddMap("model", t => t.SubCollection
                      .Where(sb => sb.State == States.InUse)
                      .OrderBy(s => s.Order)
                      .Select(s => s.Entity1.Entity2.Description)
                      .First())
                  .AddCondition("model=someFilterValue")
                  .BuildFilteringExpression();

In Linq such expressions work as expected but when I try to insert this into GridifyMapper I get various internal exceptions. I can provide those as well if required.

[uxohotteixo]

Now I know the only working approach here is to make a projection (for subcollections too) then filter and sort the projection in Gridify. But projection before filtering in EF seems to be a bad solution and will affect the quality of queries

[alirezanet]

Hi @uxohotteixo,
In the AddMap method, you can't use any filtering or Where clause since it just maps a string to the related properties. otherwise, mapping doesn't make sense.
but you can use the mapped properties in the AddConidtion method to set a default filtering on your data.
so basically according to your first example, you can map sc.Prop to something like AddMap("myProp" , ...) and use it in AddCondition method like .AddCondition("myprop=1")

[alirezanet]

The second way that comes to my mind in this scenario is to add your hard query to your collection and then use Gridify to filter it out.

var query = queriableCollection.Where(sc => sc.Any(x.Prop == "1")).ApplyFiltering(gridifyQuery);

[uxohotteixo]

@alirezanet Thank you! So I decided to move the interfering hard LINQ in the AutoMapper projection and use GridifyMapper as it should be! :)