Merge pull request #7 from SpatialFocus/feat/enum-description

Added Enum description for lookup #6

Author: pergerch

samples/SpatialFocus.EntityFrameworkCore.Extensions.SQLiteDemo/Entities/SpecialOccasion.cs

@@ -5,16 +5,23 @@
 
 namespace SpatialFocus.EntityFrameworkCore.Extensions.SQLiteDemo.Entities
 {
+	using System.ComponentModel;
+
 	public enum SpecialOccasion
 	{
+		[Description("Your birth anniversary")]
 		Birthday = 1,
 
+		[Description("Jesus' birth anniversary")]
 		Christmas,
 
+		[Description("Jesus' resurrection anniversary")]
 		Easter,
 
+		[Description("Florist holiday")]
 		Valentines,
 
-		Wedding,
+		[Description("Marriage anniversary")]
+		WeddingDay,
 	}
 }

src/SpatialFocus.EntityFrameworkCore.Extensions/EnumLookupExtension.cs

@@ -7,7 +7,9 @@ namespace SpatialFocus.EntityFrameworkCore.Extensions
 {
 	using System;
 	using System.Collections.Generic;
+	using System.ComponentModel;
 	using System.Linq;
+	using System.Reflection;
 	using Microsoft.EntityFrameworkCore;
 	using Microsoft.EntityFrameworkCore.Metadata;
 	using Microsoft.EntityFrameworkCore.Metadata.Builders;
@@ -36,9 +38,26 @@ public static void ConfigureEnumLookup(this ModelBuilder modelBuilder, EnumLooku
 
 				IMutableEntityType entityType = property.DeclaringEntityType;
 
-				Type concreteType = enumOptions.UseNumberLookup
-					? typeof(EnumWithNumberLookup<>).MakeGenericType(propertyType.GetEnumOrNullableEnumType())
-					: typeof(EnumWithStringLookup<>).MakeGenericType(propertyType.GetEnumOrNullableEnumType());
+				Dictionary<int, string> enumValueDescriptions = Enum.GetValues(propertyType.GetEnumOrNullableEnumType())
+					.Cast<Enum>()
+					.ToDictionary(Convert.ToInt32, GetEnumDescription);
+
+				bool usesDescription = enumValueDescriptions.Values.Any(x => x != null);
+
+				Type concreteType;
+				if (usesDescription)
+				{
+					concreteType = enumOptions.UseNumberLookup
+						? typeof(EnumWithNumberLookupAndDescription<>).MakeGenericType(propertyType.GetEnumOrNullableEnumType())
+						: typeof(EnumWithStringLookupAndDescription<>).MakeGenericType(propertyType.GetEnumOrNullableEnumType());
+				}
+				else
+				{
+					concreteType = enumOptions.UseNumberLookup
+						? typeof(EnumWithNumberLookup<>).MakeGenericType(propertyType.GetEnumOrNullableEnumType())
+						: typeof(EnumWithStringLookup<>).MakeGenericType(propertyType.GetEnumOrNullableEnumType());
+				}
+
 				EntityTypeBuilder enumLookupBuilder = modelBuilder.Entity(concreteType);
 
 				string typeName = propertyType.GetEnumOrNullableEnumType().Name;
@@ -54,8 +73,7 @@ public static void ConfigureEnumLookup(this ModelBuilder modelBuilder, EnumLooku
 				{
 					modelBuilder.Entity(concreteType).HasIndex(nameof(EnumWithNumberLookup<Enum>.Name)).IsUnique();
 				}
-
-				if (!enumOptions.UseNumberLookup)
+				else
 				{
 					Type converterType = typeof(EnumToStringConverter<>).MakeGenericType(propertyType.GetEnumOrNullableEnumType());
 					ValueConverter valueConverter = (ValueConverter)Activator.CreateInstance(converterType, new object[] { null });
@@ -82,10 +100,22 @@ public static void ConfigureEnumLookup(this ModelBuilder modelBuilder, EnumLooku
 						{
 							concreteType.GetProperty(nameof(EnumWithNumberLookup<object>.Id)).SetValue(instance, x);
 							concreteType.GetProperty(nameof(EnumWithNumberLookup<object>.Name)).SetValue(instance, x.ToString());
+
+							if (usesDescription)
+							{
+								concreteType.GetProperty(nameof(EnumWithNumberLookupAndDescription<object>.Description))
+									.SetValue(instance, enumValueDescriptions[(int)x]);
+							}
 						}
 						else
 						{
 							concreteType.GetProperty(nameof(EnumWithStringLookup<object>.Id)).SetValue(instance, x);
+
+							if (usesDescription)
+							{
+								concreteType.GetProperty(nameof(EnumWithNumberLookupAndDescription<object>.Description))
+									.SetValue(instance, enumValueDescriptions[(int)x]);
+							}
 						}
 
 						return instance;
@@ -96,6 +126,15 @@ public static void ConfigureEnumLookup(this ModelBuilder modelBuilder, EnumLooku
 			}
 		}
 
+		public static string GetEnumDescription(Enum value)
+		{
+			FieldInfo fieldInfo = value.GetType().GetField(value.ToString());
+
+			DescriptionAttribute attribute = (DescriptionAttribute)fieldInfo.GetCustomAttribute(typeof(DescriptionAttribute), true);
+
+			return attribute?.Description;
+		}
+
 		private static Type GetEnumOrNullableEnumType(this Type propertyType)
 		{
 			if (!propertyType.IsEnumOrNullableEnumType())

src/SpatialFocus.EntityFrameworkCore.Extensions/EnumWithNumberLookupAndDescription.cs

@@ -0,0 +1,22 @@
+// <copyright file="EnumWithNumberLookupAndDescription.cs" company="Spatial Focus">
+// Copyright (c) Spatial Focus. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+// </copyright>
+
+namespace SpatialFocus.EntityFrameworkCore.Extensions
+{
+	public class EnumWithNumberLookupAndDescription<T> : EnumWithNumberLookup<T>
+	{
+		public EnumWithNumberLookupAndDescription()
+			: base()
+		{
+		}
+
+		public EnumWithNumberLookupAndDescription(T value)
+			: base(value)
+		{
+		}
+
+		public string Description { get; set; }
+	}
+}

src/SpatialFocus.EntityFrameworkCore.Extensions/EnumWithStringLookupAndDescription.cs

@@ -0,0 +1,22 @@
+// <copyright file="EnumWithStringLookupAndDescription.cs" company="Spatial Focus">
+// Copyright (c) Spatial Focus. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+// </copyright>
+
+namespace SpatialFocus.EntityFrameworkCore.Extensions
+{
+	public class EnumWithStringLookupAndDescription<T> : EnumWithStringLookup<T>
+	{
+		public EnumWithStringLookupAndDescription()
+			: base()
+		{
+		}
+
+		public EnumWithStringLookupAndDescription(T value)
+			: base(value)
+		{
+		}
+
+		public string Description { get; set; }
+	}
+}