Skip to main content

Auto fluent mapping generation for OpenAccess/Telerik DataAccess through T4

There is two way to map code first with DB related entities. The first is data annotation which is like setting attributes and the other one is fluent mapping. Fluent mapping is very powerful and flexible approach to map entities. The only downside of fluent mapping is incompatibility with client side validation where as MVC has inbuilt functionality to validate on client side with data annotation.

We will look into basic fluent mapping generation along with data annotation if present. Default data annotation is not compatible with Telerik DataAccess/OpenAccess. This article does not gives information about how fluent mapping works or how to generate it but auto generation of fluent mapping by any give model.

Pre-requisites for fluent generation
I have took help of two different libraries to generate fluent mapping for OpenAccess.
- MultiOutput.ttinclude (https://github.com/subsonic/SubSonic-3.0-Templates/blob/master/ActiveRecord/MultiOutput.ttinclude) : This is to generate multiple files through single T4 file.
- VisualStudioAutomationHelper.ttinclude (https://github.com/PombeirP/T4Factories/blob/master/T4Factories.Testbed/CodeTemplates/VisualStudioAutomationHelper.ttinclude) : This will help us in reading existing models and refactoring through EnvDte library.

Guide to be followed for generation:

 Choose the path to include above files (In my case those are kept in T4Plugin):
<#@ include file="../../T4Plugin/VisualStudioAutomationHelper.ttinclude" #>

<#@ include file="../../T4Plugin/MultiOutput.ttinclude" #>

 White-listing and black listing properties
var whiteListPropertyTypes = new List<string>(){};

var blackListedPropertyNames = new List<string>();
In whiteListPropertyTypes list, we can specify the custom types that need to be included. Like some enumeration types. In same way some properties could be excluded by help of blackListedPropertyNames list.

Listing classes for generation of fluent mapping
var codeClass in allClasses.OfType<CodeClass2>()
        .Where(clas=> clas!=null && clas.FullName.StartsWith("T4FluentMapping.DomainModel") &&

        !clas.FullName.EndsWith("MetadataSource"))
This code will list up all classes starts with T4FluentMapping.DomainModel and excludes class ends with MetadataSource.

That is all needed to generate basic fluent mapping. Here the all code goes:
-----------------------------------------------------------------------------------------------
<#@ template  debug="true" hostSpecific="true" #>
<#@ output extension=".cs" #>
<#@ Assembly Name="EnvDTE" #>
<#@ Assembly Name="EnvDTE80" #>
<#@ Assembly name="System.ComponentModel.DataAnnotations" #>
<#@ import namespace="EnvDTE" #>
<#@ import namespace="EnvDTE80" #>
<#@ import namespace="System" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Collections" #>
<#@ import namespace="System.Collections.Generic" #> 
<#@ import namespace="System.ComponentModel.DataAnnotations" #>
<#@ import namespace="System.Text.RegularExpressions" #>
<#@ include file="../../T4Plugin/VisualStudioAutomationHelper.ttinclude" #>
<#@ include file="../../T4Plugin/MultiOutput.ttinclude" #>

 <#

     // get a reference to the project of this t4 template
    var project = VisualStudioHelper.CurrentProject;

     // get all class items from the code model
    var allClasses = VisualStudioHelper.GetAllCodeElementsOfType(project.CodeModel.CodeElements, EnvDTE.vsCMElement.vsCMElementClass, false);

     // TODO: Extra parameter type to get it listed
    // Ex: Model.Enumeration.DbOperation
var whiteListPropertyTypes = new List<string>(){};
var blackListedPropertyNames = new List<string>();

     // iterate all classes
    foreach(var codeClass in allClasses.OfType<CodeClass2>()
        .Where(clas=> clas!=null && clas.FullName.StartsWith("T4FluentMapping.DomainModel") &&
        !clas.FullName.EndsWith("MetadataSource")))
    {
        var fileName=codeClass.Name+"Mapping.Generated.cs";
        #>
namespace T4FluentMapping.Model.Mapping.FluentMapping
{
    //------------------------------------------------------------------------------
    // <auto-generated>
    //     This code was generated from a template and will be re-created if deleted
    //   with default values if executed.
    // </auto-generated>
    //------------------------------------------------------------------------------
    using Telerik.OpenAccess.Metadata;
    using Telerik.OpenAccess.Metadata.Fluent;

     /// <summary>
    /// Fluent mapping for <see cref="<#=            codeClass.FullName#>"/>
    /// </summary>
    public partial class <#=            codeClass.Name#>Mapping
   : MappingConfiguration<<#=            codeClass.FullName #>>
    {
        /// <summary>
        /// Initializes a basic fluent mappings for <see cref="<#=            codeClass.FullName#>" />
        /// </summary>
   public void InitializeBasicMappings()
   {
   this.MapType(map => new
   {
<#
        // iterate all properties
        var allProperties = VisualStudioHelper.GetAllCodeElementsOfType(codeClass.Members, EnvDTE.vsCMElement.vsCMElementProperty, true);
        foreach(EnvDTE.CodeProperty property in allProperties
.Where(prop=>(prop as CodeProperty2).ReadWrite == vsCMPropertyKind.vsCMPropertyKindReadWrite))
        {
            // for excluding property
            var commentForFieldValue = ((property.Name == "FieldValue" && codeClass.Name == "SystemDataField" )
|| blackListedPropertyNames.Any(propName=>propName == property.Name)
)?"//":String.Empty;
            if (IsPrimitive(property.Type) || whiteListPropertyTypes.Contains(property.Type.AsFullName))
            {
        #>
                <#=commentForFieldValue#>map.<#=property.Name #>,
<#          
            }
            #>
<#
        }
        #>
            }).ToTable("<#= codeClass.Name #>");

 // Data annotation mappings
<#
// For data annotation attribute mapping
foreach(EnvDTE.CodeProperty property in allProperties)
{
if(IsType(property.Type,typeof(bool)))
{
#>this.HasProperty(model => model.<#=property.Name#>).HasColumnType("bit");
<#
}

 foreach(var attribute in GetAttributes(property))
{
if(attribute.Name == "Required")
{
#>this.HasProperty(model => model.<#=property.Name#>).IsNotNullable();
<#
}
if(attribute.Name == "MaxLength")
{
#>this.HasProperty(model => model.<#=property.Name#>).HasColumnType("varchar").HasLength(<#=attribute.Value#>);
<#
}
if(attribute.Name == "StringLength")
{
#>this.HasProperty(model => model.<#=property.Name#>).HasColumnType("varchar").HasLength(<#=attribute.Value#>);
<#
}
}
if(whiteListPropertyTypes.Contains(property.Type.AsFullName))
{
#>this.HasProperty(model => model.<#=property.Name#>);
<#
}
if(IsNullable(property.Type))
{
#>this.HasProperty(model => model.<#=property.Name#>).IsNullable();
<#
}
}#>
}
    }
}
<#
    SaveOutput(fileName);
DeleteOldOutputs();
    }
#>

 <#+
    // Support C# and VB syntax
    private static readonly Regex _unwrapNullableRegex = new Regex(@"^System.Nullable(<|\(Of )(?<UnderlyingTypeName>.*)(>|\))$");

 private static Type[] _primitiveList;

 private static void InitializePrimitives()
{
if(_primitiveList == null)
{
var types = new[]
{
typeof (Enum),
typeof (String),
typeof (Char),

 typeof (Boolean),
typeof (Byte),
typeof (Int16),
typeof (Int32),
typeof (Int64),
typeof (Single),
typeof (Double),
typeof (Decimal),

 typeof (SByte),
typeof (UInt16),
typeof (UInt32),
typeof (UInt64),

 typeof (DateTime),
typeof (DateTimeOffset),
typeof (TimeSpan),
};
var nullTypes = from t in types
where t.IsValueType
select typeof (Nullable<>).MakeGenericType(t);

 _primitiveList = types.Concat(nullTypes).ToArray();
}
}
   /// <summary>
    /// Determines whether the supplied CodeTypeRef represents a primitive .NET type, e.g.,
    /// byte, bool, float, etc.
    /// </summary>
    public static bool IsPrimitive(CodeTypeRef codeTypeRef)
    {
InitializePrimitives();
return _primitiveList.Any(item => item.FullName == codeTypeRef.AsFullName || _unwrapNullableRegex.Match(codeTypeRef.AsFullName).Success);
    }

 public static bool IsNullable(CodeTypeRef codeTypeRef)
    {
return _unwrapNullableRegex.Match(codeTypeRef.AsFullName).Success;
    }

 public static IEnumerable<CodeAttribute> GetAttributes(CodeProperty codeProperty)
{
return codeProperty.Attributes.OfType<CodeAttribute>().ToList();
}

     public static bool IsType<T>(CodeTypeRef codeTypeRef)
    {
        return IsType(codeTypeRef , typeof(T));
    }
 
public static bool IsType(CodeTypeRef codeTypeRef, Type type)
    {
return codeTypeRef.AsFullName == type.ToString() || codeTypeRef.AsFullName == "System.Nullable<"+ type.ToString()+ ">";
    }
 #>
-----------------------------------------------------------------------------------------------



Labels:

Comments

Post a Comment

Popular posts from this blog

Using Redis distributed cache in dotnet core with helper extension methods

Redis cache is out process cache provider for a distributed environment. It is popular in Azure Cloud solution, but it also has a standalone application to operate upon in case of small enterprises application. How to install Redis Cache on a local machine? Redis can be used as a local cache server too on our local machines. At first install, Chocolatey https://chocolatey.org/ , to make installation of Redis easy. Also, the version under Chocolatey supports more commands and compatible with Official Cache package from Microsoft. After Chocolatey installation hit choco install redis-64 . Once the installation is done, we can start the server by running redis-server . Distributed Cache package and registration dotnet core provides IDistributedCache interface which can be overrided with our own implementation. That is one of the beauties of dotnet core, having DI implementation at heart of framework. There is already nuget package available to override IDistributedCache i...
3 comments
Read more

Kendo MVC Grid DataSourceRequest with AutoMapper - Advance

The actual process to make DataSourceRequest compatible with AutoMapper was explained in my previous post  Kendo MVC Grid DataSourceRequest with AutoMapper , where we had created custom model binder attribute and in that property names were changed as data models. In this post we will be looking into using AutoMapper's Queryable extension to retrieve the results based on selected columns. When  Mapper.Map<RoleViewModel>(data)  is called it retrieves all column values from table. The Queryable extension provides a way to retrieve only selected columns from table. In this particular case based on properties of  RoleViewModel . The previous approach that we implemented is perfect as far as this article ( 3 Tips for Using Telerik Data Access and AutoMapper ) is concern about performance where it states: While this functionality allows you avoid writing explicit projection in to your LINQ query it has the same fatal flaw as doing so - it prevents the qu...
Post a Comment
Read more

C# Response files

Response files are similar to batch files, having some specific instruction. On execution they perform some predefined task based on instruction. Response file contains instruction to compile programs. If we have to build complex program through command line then response files are really helpful in development process. rsp is an extension for response files. By default, csc.rsp file exists under "Framework" folder Ex: C:\Windows\Microsoft.NET\Framework\v4.0.30319. csc.rsp contains long list of system references (dlls). Some contents under csc.rsp # Reference the common Framework libraries /r:Accessibility.dll /r:Microsoft.CSharp.dll /r:System.Configuration.dll /r:System.Configuration.Install.dll /r:System.Core.dll /r:System.Data.dll /r:System.Data.DataSetExtensions.dll /r:System.Data.Linq.dll .......... In same way we can have our own response file defined which might include some third party dll. Let's see an example. Suppose we have to create an appli...
Post a Comment
Read more

Trim text in MVC Core through Model Binder

Trimming text can be done on client side codes, but I believe it is most suitable on MVC Model Binder since it would be at one place on infrastructure level which would be free from any manual intervention of developer. This would allow every post request to be processed and converted to a trimmed string. Let us start by creating Model binder using Microsoft.AspNetCore.Mvc.ModelBinding; using System; using System.Threading.Tasks; public class TrimmingModelBinder : IModelBinder { private readonly IModelBinder FallbackBinder; public TrimmingModelBinder(IModelBinder fallbackBinder) { FallbackBinder = fallbackBinder ?? throw new ArgumentNullException(nameof(fallbackBinder)); } public Task BindModelAsync(ModelBindingContext bindingContext) { if (bindingContext == null) { throw new ArgumentNullException(nameof(bindingContext)); } var valueProviderResult = bindingContext.ValueProvider.GetValue(bin...
2 comments
Read more

MongoDB navigation property or making it behave as ORM in .Net

This is an implementation to make models to have  navigation properties work like ORM does for us. What actually happens in ORM to make navigation properties work? Entity Framework has proxy classes implementation to allow lazy loading and eager loading implementation. While creating proxy classes it also changes definitions for actual classes to make navigation properties work to get values based on Model's for navigation properties. Most of ORMs work in same fashion like Telerik DataAccess has enhancer tool which changes class definition at compile time to enable navigation properties. In this implementation, we would retain the original class but we would have extension methods to allow initializing properties to have navigation proprieties work. Let's first create desire model on which we need to implement. I am picking up simple one-to-many relationship example from Person to Address. public class Person { public int PersonId { get; set; } ...
Post a Comment
Read more

Kendo MVC Grid DataSourceRequest with AutoMapper

Kendo Grid does not work directly with AutoMapper but could be managed by simple trick using mapping through ToDataSourceResult. The solution works fine until different filters are applied. The problems occurs because passed filters refer to view model properties where as database model properties are required after AutoMapper is implemented. So, the plan is to intercept DataSourceRequest  and modify names based on database model. To do that we are going to create implementation of  CustomModelBinderAttribute to catch calls and have our own implementation of DataSourceRequestAttribute from Kendo MVC. I will be using same source code from Kendo but will replace column names for different criteria for sort, filters, group etc. Let's first look into how that will be implemented. public ActionResult GetRoles([MyDataSourceRequest(GridId.RolesUserGrid)] DataSourceRequest request) { if (request == null) { throw new Argume...
Post a Comment
Read more

Dependency Injection through XML configuration and XML transformation through SlowCheetah

Dependency Injection (DI) is a design pattern to change definition by substituting object without changing code for the application. The most popular DI type is to construct classes based on certain interface and pass actual object on constructor level. What are we trying to do? We will be looking into a way to achieve dependency injection through XML configuration based on  build selection . The implemented classes derived through interface will get switched based on build selection. Where to use it? I really hate making dependencies with something specific which can be changed later on. In my case, Azure environment. I believe Azure is more like a platform where we can host the application rather then integrating the application with Azure. What if client decided to switch to other hosting environment, in that case we got to change every piece of code wherever Azure SDKs are referred. The above one is merely an example. We can use this approach on many other item as wel...
Post a Comment
Read more

Blazor 0.5.0 Interop JavaScript from C# and C# to JavaScript call

Blazor provides two-way communication from JS to C# and C# to JS which is called Interop. The version upgrade to Blazor 0.5.0 changed the approach in interactions between cshtml and JS files. The newer version simplifies JS calling by avoiding pre-registration of JS function. In this article, we would see how to call a JS method by passing multiple parameters from cshtml and parameterized call from JS to cshtml. The scenario that is used in this article has a Kendo AutoComplete to search book and populate information based on the selection. An example of a call to JS from cshtml await JSRuntime.Current.InvokeAsync<string>( "searchBook.Init", "#SearchTitle", new DotNetObjectRef(this)); Takeaways from the above example: - JSRuntime.Current give environment to execute out-process JS. - InvokeAsync is a function that would allow executing the JS function. - The searchBook.Init is a JS function call, we would see it in details in the second sec...
Post a Comment
Read more

Architecture solution composting Repository Pattern, Unit Of Work, Dependency Injection, Factory Pattern and others

Project architecture is like garden, we plant the things in certain order and eventually they grow in similar manner. If things are planted well then they will all look(work) great and easier to manage. If they grow as cumbersome it would difficult to maintain and with time more problems would be happening in maintenance. There is no any fixed or known approach to decide project architecture and specially with Agile Methodology. In Agile Methodology, we cannot predict how our end products will look like similarly we cannot say a certain architecture will fit well for entire development lifespan for project. So, the best thing is to modify the architecture as per our application growth. I understand that it sounds good but will be far more problematic with actual development. If it is left as it is then more problems will arise with time. Just think about moving plant vs a full grown tree. Coming to technical side, In this article, I will be explaining about the various techniques ...
Post a Comment
Read more

Making FluentValidation compatible with Swagger including Enum or fixed List support

FluentValidation is not directly compatible with Swagger API to validate models. But they do provide an interface through which we can compose Swagger validation manually. That means we look under FluentValidation validators and compose Swagger validator properties to make it compatible. More of all mapping by reading information from FluentValidation and setting it to Swagger Model Schema. These can be done on any custom validation from FluentValidation too just that proper schema property has to be available from Swagger. Custom validation from Enum/List values on FluentValidation using FluentValidation.Validators; using System.Collections.Generic; using System.Linq; using static System.String; /// <summary> /// Validator as per list of items. /// </summary> /// <seealso cref="PropertyValidator" /> public class FixedListValidator : PropertyValidator { /// <summary> /// Gets the valid items /// <...
1 comment
Read more