Using Base Specification Class (#56)

* Ardalis/upgrade1 (#44)

* Upgrading to netcore 2.0
Updating repository to support async options and refactoring to use it.

* Starting work on tracking customer orders feature.

* Cleaning up some bugs
Working on basket view component implementation

* Fixing up styles, especially for basket in header.

* Adding Order Features (#47)

* Working on order model binding from checkout page - WIP

* Small layout tweaks (#43)

* Updating quantities implemented.

* Fixed basket widget count

* Order History (#49)

* working on creating and viewing orders.
* Working on wiring up listing of orders
* List orders page works as expected. Needed to support ThenInclude scenarios. Currently using strings.

* Remove non-icon basket link from header
Add comments to EF query logic

* Refactoring to use base specification type

* minor cleanup

src/ApplicationCore/Specifications/BaseSpecification.cs

@@ -0,0 +1,27 @@
+using ApplicationCore.Interfaces;
+using System;
+using System.Linq.Expressions;
+using System.Collections.Generic;
+
+namespace ApplicationCore.Specifications
+{
+    public abstract class BaseSpecification<T> : ISpecification<T>
+    {
+        public BaseSpecification(Expression<Func<T, bool>> criteria)
+        {
+            Criteria = criteria;
+        }
+        public Expression<Func<T, bool>> Criteria { get; }
+        public List<Expression<Func<T, object>>> Includes { get; } = new List<Expression<Func<T, object>>>();
+        public List<string> IncludeStrings { get; } = new List<string>();
+
+        protected virtual void AddInclude(Expression<Func<T, object>> includeExpression)
+        {
+            Includes.Add(includeExpression);
+        }
+        protected virtual void AddInclude(string includeString)
+        {
+            IncludeStrings.Add(includeString);
+        }
+    }
+}