Merge pull request #23 from dmacko/master

Fix for issue #22

Sieve/Services/SieveProcessor.cs

@@ -127,10 +127,12 @@ namespace Sieve.Services
                     var converter = TypeDescriptor.GetConverter(property.PropertyType);
                     var parameter = Expression.Parameter(typeof(TEntity), "e");
 
-                    dynamic filterValue = Expression.Constant(
-                        converter.CanConvertFrom(typeof(string)) ?
-                        converter.ConvertFrom(filterTerm.Value) :
-                        Convert.ChangeType(filterTerm.Value, property.PropertyType));
+                    
+                    dynamic constantVal = converter.CanConvertFrom(typeof(string))
+                                              ? converter.ConvertFrom(filterTerm.Value)
+                                              : Convert.ChangeType(filterTerm.Value, property.PropertyType);
+
+                    Expression filterValue = GetClosureOverConstant(constantVal);
 
                     dynamic propertyValue = Expression.PropertyOrField(parameter, property.Name);
 
@@ -201,6 +203,14 @@ namespace Sieve.Services
             return result;
         }
 
+        //Workaround to ensure that the filter value gets passed as a parameter in generated SQL from EF Core
+        //See https://github.com/aspnet/EntityFrameworkCore/issues/3361
+        private Expression GetClosureOverConstant<T>(T constant)
+        {
+            Expression<Func<T>> closure = () => constant;
+            return closure.Body;
+        }
+
         private IQueryable<TEntity> ApplySorting<TEntity>(
             ISieveModel<IFilterTerm, ISortTerm> model, 
             IQueryable<TEntity> result,

SieveTests/Entities/Post.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq;
 using System.Threading.Tasks;
 using Sieve.Attributes;
@@ -21,5 +22,9 @@ namespace SieveTests.Entities
 
         [Sieve(CanFilter = true, CanSort = true)]
         public DateTimeOffset DateCreated { get; set; } = DateTimeOffset.UtcNow;
+
+        [Sieve(CanFilter = true, CanSort = true)]
+        [Column(TypeName = "datetime")]
+        public DateTime DateLastViewed { get; set; } = DateTime.UtcNow;
     }
 }

SieveTests/Migrations/20180522013323_AddDateLastViewedColumn.Designer.cs

@@ -0,0 +1,47 @@
+// <auto-generated />
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage;
+using Microsoft.EntityFrameworkCore.Storage.Internal;
+using SieveTests.Entities;
+using System;
+
+namespace SieveTests.Migrations
+{
+    [DbContext(typeof(ApplicationDbContext))]
+    [Migration("20180522013323_AddDateLastViewedColumn")]
+    partial class AddDateLastViewedColumn
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "2.0.1-rtm-125")
+                .HasAnnotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);
+
+            modelBuilder.Entity("SieveTests.Entities.Post", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("CommentCount");
+
+                    b.Property<DateTimeOffset>("DateCreated");
+
+                    b.Property<DateTime>("DateLastViewed")
+                        .HasColumnType("datetime");
+
+                    b.Property<int>("LikeCount");
+
+                    b.Property<string>("Title");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Posts");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

SieveTests/Migrations/20180522013323_AddDateLastViewedColumn.cs

@@ -0,0 +1,26 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+using System;
+using System.Collections.Generic;
+
+namespace SieveTests.Migrations
+{
+    public partial class AddDateLastViewedColumn : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<DateTime>(
+                name: "DateLastViewed",
+                table: "Posts",
+                type: "datetime",
+                nullable: false,
+                defaultValue: new DateTime(1, 1, 1, 0, 0, 0, 0, DateTimeKind.Unspecified));
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "DateLastViewed",
+                table: "Posts");
+        }
+    }
+}

SieveTests/Migrations/ApplicationDbContextModelSnapshot.cs

@@ -29,6 +29,9 @@ namespace SieveTests.Migrations
 
                     b.Property<DateTimeOffset>("DateCreated");
 
+                    b.Property<DateTime>("DateLastViewed")
+                        .HasColumnType("datetime");
+
                     b.Property<int>("LikeCount");
 
                     b.Property<string>("Title");