Generic Repository Specification Pattern - Adding Filtering

One of the drawbacks about using the specification pattern is that we lose some of the functions provided by Entity Framework. Filtering the result is one of them and we will see how we can manually create the feature with the specification pattern.

Creating a Generic Repository Pattern

Relational DB - Getting Data including Data from Other Entities (Generic Repository Pattern)

 

Go to the individual specification class under the core folder and add parameters to filter (in this example, 'targetId' and 'typeId') and add the code that implement the where clause in the base as shown below

: base(x => 
  (!targetId.HasValue || x.ItemTargetId == targetId) &&
  (!typeId.HasValue || x.ItemTypeId == typeId)
)

Go to the controller and add filtering parameters and pass that parameters to the individual specification class

Run

Move to the API folder

cd /API

And run the app

dotnet watch

In this writing, we have seen one of ways to add filtering with the specification pattern.