.Net al punto - Juan Francisco Morales Larios

Fluent MVVM

• QuickStart
• Auto ViewModel
• ViewBag Property
• Easy events commands
• Messenger
• Multi IoC
• Self Loading

AutoViewModel

AutoViewModel is a Fluent MVVM features to auto instantiate our ViewModels classes. Its objective is simplified as far as possible ViewModels classes with same performance and stability.
AutoViewModelmark> isn’t mandatory, so that we can use any other technique.
AutoViewModelmark> has a basic rule that showing the following image.

The View class name and the ViewModel class name have to be the same preceded by suffix View for the View class and ViewModel for the ViewModel class.

• SameNameClass[View].xaml / cs
• SameNameClass[ViewModel].cs

A Example

• MyView.xaml / cs
• MyViewModel.cs

We will add our ViewModel class following the general autoInstace rule so that, its name will be MyViewModel.cs.

AutoViewModel Class

AutoViewModel.cs class is a Fluent MVVM ViewModel instance control class. It is in MoralesLarios.FluentMVVM.Infrastructure namespace and is a static class with 2 AttachDependency properties.

• IsAutoMaticViewModelInstance
• Is a bool property, false is its default value. If this property is true, AutoViewModel engine will try to instantiate its ViewModel class referred (this class must comply with the previous main nomenclature rule). If is false, it will do nothing.


• ViewModelClassName
• Is a string property. If your ViewModelClass doesn’t follow the main nomenclature rule, you set the ViewModelClass name in this property.

Internal Class Search Rule

When AutoViewModel engine search ViewModelClass to instantiate, follow the next rule:
In the case we have added an IoC in our project, this will be the first place to search. If there isn’t IoC or ViewModelClas isn’t in the IoC configurations types, The AutoViewModel engine search in all project. This rule is valid to two different searches (IsAutoMaticViewModelInstance and ViewModelClassName).

Important: If you don’t setup your ViewModel class in IoC, your ViewModel class a constructor without parameters.

Examples

This are 4 types AutoViewModel configuration. We will create an example for each.

Our example has an initial Fluent MVVM configuration only with nuget package and IoC configuration. For more info QuickStart and Multi IoC sections.
We will build 2 Views and 2 ViewModels, a couple for those who comply with nomemclature rules and another for those who don’t comply.
Will change IoC configuration to demonstrate it has preference over another project classes.
We show IoC Fluent MVVM configuration with empty instances registered.

using Autofac;
using MoralesLarios.FluentMVVM.Infrastructure.IoC;
using System;

namespace FluentMVVMExamplesDesc.AutoViewModelApp.IoC
{
    class BootStrapper : IContainerIoCWorker
    {
        public IContainer Container { get; private set; }

        public void RegisterTypes()
        {
            var builder = new ContainerBuilder();

            // Empty

            Container = builder.Build();
        }

        public object ResolveObject(Type type)
        {
           if (type == null) return null;
           
            object result = null;
            
            result = Container.TryResolve(type, out result);

            return result;
        }

        public T ResolveType<T>()
        {
            if (type == null) return null;
           
            T result = default(T);
            
            Container.TryResolve<T>(out result);

            return result;
        }


    }
}

Example 1: ViewModel class with nomenclature rule without IoC

• The first step is add a simple WPF Window View WithRuleView.xaml .
  
• The second step is add ViewModel WithRuleViewModel.xaml .

AS we can check it meets naming rule.



WithRuleViewModel.cs code.





namespace FluentMVVMExamplesDesc.AutoViewModelApp.ViewModels
{
    using MoralesLarios.FluentMVVM;

    public class WithRuleViewModel : ViewModelBase
    {

        public WithRuleViewModel()
        {

        }

    }
}




• Add MoralesLarios.FluentMVVM namespace
• We have inhherited from ViewModelBase
• Add a constructor to check in debug.



• Completed code in WithRuleView.xaml .
  

  
  

  <Window x:Class="FluentMVVMExamplesDesc.AutoViewModelApp.WithRuleView"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
          xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
          xmlns:local="clr-namespace:FluentMVVMExamplesDesc.AutoViewModelApp"
          xmlns:fluent="clr-namespace:MoralesLarios.FluentMVVM.Infrastructure;assembly=MoralesLarios.FluentMVVM"
          fluent:AutoViewModelClass.IsAutomaticViewModelInstance="True"
          mc:Ignorable="d"
          Title="WithRuleView" Height="359" Width="602">
      <Grid>
  
      </Grid>
  </Window>
  

  
  

  • Add MoralesLarios.FluentMVVM.Infraestructure xaml namespace
  • Add a AutoViewModelClass.IsAutomaticViewModelInstance to true value.

  
  

With these simple steps, Fluent MVVM already be ready to auto instantiate ViewModel class automatically.

Result.

When we auto instantiate non IoC setup classes, these classes have to be parameterless constructor, otherwise, they will throw an exception.

All process in video.

Example 2: ViewModel class with nomenclature rule with IoC

To give more value to example, we will add a dependency injection in our ViewModel.

public class WithRuleViewModel : ViewModelBase
{
    private readonly IMyInjection _myInjection;

    public WithRuleViewModel(IMyInjection myInjection)
    {
        _myInjection = myInjection;
    }

}

IMyInjection is my dependency injection.

In this moment will add our WithRuleViewModel and MyInjection classes in IoC configuration. With this action

public void RegisterTypes()
{
    var builder = new ContainerBuilder();

    builder.RegisterType<WithRuleViewModel>().AsSelf();

    builder.RegisterType<MyInjection>().As<IMyInjection>();

    Container = builder.Build();
}

This method is part of BootStraper.cs.

Result.

All process in video.

Example 3: ViewModel class without nomenclature rule with IoC

It’s time to add a new View and a new ViewModel. For these new examples don’t must not comply the nomenclature rule.

• The first step is add a simple WPF Window View WithoutRuleView.xaml .
  
• The second step is add ViewModel NoRuleViewModel.xaml .

AS we can check it don't meets naming rule.



WithoutRuleViewModel.cs code.





namespace FluentMVVMExamplesDesc.AutoViewModelApp.ViewModels
{
    using MoralesLarios.FluentMVVM;

    public class WithoutRuleViewModel : ViewModelBase
    {

        public WithoutRuleViewModel()
        {

        }

    }
}




• Add MoralesLarios.FluentMVVM namespace
• We have inhherited from ViewModelBase
• Add a constructor to check in debug.



• Completed code in WithoutRuleView.xaml .
  

  
  

  <Window x:Class="FluentMVVMExamplesDesc.AutoViewModelApp.WithRuleView"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
          xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
          xmlns:local="clr-namespace:FluentMVVMExamplesDesc.AutoViewModelApp"
          xmlns:fluent="clr-namespace:MoralesLarios.FluentMVVM.Infrastructure;assembly=MoralesLarios.FluentMVVM"
          fluent:AutoViewModelClass.ViewModelClassName="NoRuleViewModel"
          mc:Ignorable="d"
          Title="WithoutRuleView" Height="359" Width="602">
      <Grid>
  
      </Grid>
  </Window>
  

  
  

  • Add MoralesLarios.FluentMVVM.Infraestructure xaml namespace
  • Add a AutoViewModelClass.ViewModelClassName to NoRuleViewModel value. Our ViewModel class name without extension.

  
  

With these simple steps, Fluent MVVM already be ready to auto instantiate ViewModel class automatically.

Result.

When we auto instantiate non IoC setup classes, these classes have to be parameterless constructor, otherwise, they will throw an exception.

All process in video.

Example 4: ViewModel class without nomenclature rule with IoC

Same as in Example 2, to give more value to example, we will add a dependency injection in our ViewModel.

public class NoRuleViewModel : ViewModelBase
{
    private readonly IMyInjection _myInjection;

    public NoRuleViewModel(IMyInjection myInjection)
    {
        _myInjection = myInjection;
    }

}

IMyInjection is my dependency injection.

In this moment will add our WithRuleViewModel and MyInjection classes in IoC configuration. With this action

public void RegisterTypes()
{
    var builder = new ContainerBuilder();

    builder.RegisterType<WithRuleViewModel>().AsSelf();
    
    builder.RegisterType<NoRuleViewModel>().AsSelf();

    builder.RegisterType<MyInjection>().As<IMyInjection>();
    
    

    Container = builder.Build();
}

This method is part of BootStraper.cs.

Result.

All process in video.




Download AutoViewModel (AutoViewModel proyect) Code