DTDMVVM

A view-model binder for WPF which operates on data templates and uses a naming convention for locating views (Data-Template-Driven Model-View-ViewModel).

Through WPF's implicit data template application, a view-model first approach to MVVM can easily be realized. Implicit data templates have their DataType set to the type of object they should be applied to. This micro-framework automates the process of creating such templates, hooking up view-models with views (commonly sub-classes of UserControl).

Usage

The method DataTemplateCreator.CreateViewModelDataTemplates(Assembly) iterates the types of the given assembly, looking for a match to the naming convention ViewModel ⇒ View, i.e. the name of the view-model must contain ViewModel and all instances of the phrase will be replaced with View to locate the corresponding view class. (View model and view must be public.)

An example of matching namespace/class names:

MyApp.ViewModels.Menu:FileMenuViewModel
MyApp.Views.Menu:FileMenuView

(Replacing ViewModel in ViewModels, conveniently yields Views.)

The DataTemplate that would be created would look something like this:

<DataTemplate xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:vm="clr-namespace:MyApp.ViewModels.Menu;assembly=MyApp"
              DataType="{x:Type vm:FileMenuViewModel}">
    <v:FileMenuView xmlns:v="clr-namespace:MyApp.Views.Menu;assembly=MyApp"/>
</DataTemplate>

There are no explicit bindings set up, so the DataContext inside the view will be the view-model.

The CreateViewModelDataTemplates method returns a ResourceDictionary, which can, for example, be added to the MergedDictionaries of the Application.Resources:

using System;
using System.Reflection;
using System.Windows;
using DTDMVVM;

public partial class App : Application
{
  protected override void OnStartup(StartupEventArgs e)
  {
    var assembly = Assembly.GetAssembly(typeof(App));
    var templates = DataTemplateCreator.CreateViewModelDataTemplates(assembly);
    Resources.MergedDictionaries.Add(templates);
  }
}

These templates are then automatically applied when e.g. a ContentPresenter.Content is bound to a view model instance, or an ItemsControl.ItemsSource is bound to a view model list.

Special Cases

Hierarchical Data Templates

For controls like the TreeView, a HierarchicalDataTemplate may be required. To make the template creator handle this, there is a HierarchicalViewAttribute which takes as argument the name of the property, the HierarchicalDataTemplate.ItemsSource should bind to.

Generics

Sadly, generics are currently not supported. The implicit data template application mechanism does not seem to apply templates to generic type instances.

Utilities

The DTDMVVM.Utility namespace provides two simple utility classes:

• ViewModelBase: Base class implementing INotifyPropertyChanged and IDataErrorInfo.
• Command: A delegate-based ICommand implementation.