[Entity Framework 6] DB First - Create Metadata class and services with T4

 C#   Entity Framework   Code-first

▌Introduction

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This articles was inspired by WASICHRIS’ article:

[Entity Framework] 利用T4快速建立Entity Data Model之MetaData類別

Since I have a UOW (Unit of work) pattern on my Entity Framework 6 library, every POCO entity should inherits the base entity class and has its own CRUD service class as following,

PS. We need to create a Partial class which inherits UowEntity in DB-first.

However the time for creating the Partial classes and Service classes for a whole new DB-first data model (ADO.NET Entity Data Model) is expensive, so that we will use T4 to generate them automatically.

▋Related articles

[Entity Framework 6] Use MetadataType to define the attribure of DAO properties

[Visual Studio 2015] Create and distribute a Poject Template with Wizard (1)

[Visual Studio 2015] Create and distribute a Poject Template with Wizard (2)

▌Environment

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▋Visual Studio 2017 community

▋Entity Framework 6.1.3

▌Implement

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▋T4 for Models

OK, the code is complex and I won’t give too much explanation on it.

The flow is,

1.  Load .edmx and get all entity types (EntityType) from it

2.  For every EntityType, generate a .cs file with same class name (if not exists)

3.  Write namespaces and partial class structure into the .cs file

Gist for EdmxModel-metadata.tt

Gist for EdmxModel-simple.tt





The difference between EdmxModel-metadata.tt and EdmxModel-simple.tt:

1.   The partial class created from EdmxModel-metadata.tt inherits UowEntity and defines the MetadataType

2.   The partial class created from EdmxModel-simple.tt only inherits UowEntity

Assume that there is a POCO: MyModel in EDMX, the above T4 will generate:

1.  MyModels.cs (by EdmxModel-simple.tt)

2.  MyModelsMetadata.cs (by EdmxModel-metadata.tt)

And their contents:

▋MyModels.cs

namespace JB.Infra.Util.EF.Models

{

    using System;

    using System.Collections.Generic;

   

    public partial class MyModels

    {

        public int Id { get; set; }

        public string Name { get; set; }

        public string Department { get; set; }

    }

}

▋MyModelsMetadata.cs

using System;

using System.ComponentModel;

using System.ComponentModel.DataAnnotations;

using JB.Infra.Util.EF.Entity;

namespace JB.Infra.Utility.EF.DbFirst.UnitTest.Models

{

    /// <summary>

    /// MyModels class

    /// </summary>

    [Description("My Models")]

    [MetadataType(typeof(MyModelsMetadata))]

    public partial class MyModels : UowEntity

    {

    }

    /// <summary>

    /// MyModels Metadata class

    /// </summary>

    internal class MyModelsMetadata

    {

        /// <summary>

        /// Id

        /// </summary>       

        [DisplayName("Id")]

        [Description("Id")]

        [Required(ErrorMessage = "Id is required")]

        public int Id { get; set; }

        /// skip ...

▋T4 for Services

Same process on generating CRUD Service class.

Notice the relative path of .edmx is updated to “../Models”

Gist for EdmxService.tt

Result:

▌Reference

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▋ [Entity Framework] 利用T4快速建立Entity Data Model之MetaData類別