XAML without the .xaml.cs code behind files

Question

I'm using WPF with the Model-View-ViewModel pattern. Thus, my code behind files (.xaml.cs) are all empty, except for the constructor with a call to InitializeComponent. Thus, for every .xaml file I have a matching, useless, .xaml.cs file.

I swear I read somewhere that if the code behind file is empty except for the constructor, there is a way to delete the file from the project altogether. After searching the net, it seems that the appropriate way to do this is to use the 'x:Subclass' attribute:

<UserControl
    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"
    mc:Ignorable="d"
    xmlns:toolkit="http://schemas.microsoft.com/wpf/2008/toolkit"
    x:Class="MyNamespace.MyClass"
    x:Subclass="UserControl"
    d:DesignWidth="700" d:DesignHeight="500">

This does the following in the generated .g.cs file:

1. Removes the 'partial' class modifier on MyClass.
2. Adds the class 'UserControl' in to its subclass list.

Seems perfect. Indeed, if you still have the .xaml.cs file in the build, it no longer compiles because of the missing partial--so I'm thinking this must be correct. However, if I remove the superfluous file from the build and run, the control does not get initialized correctly (it is blank). This is, I presume, because InitializeComponent() is not getting called. I see InitializeComponent is not virtual, so it seems there would be no way for the base class to call it (short of using reflection).

Am I missing something?

Thanks!

Eric

Answer 1

As another option, if you don't want to go all the way to using DataTemplates, here is an alternate approach for UserControls:

Use the x:Code attribute to embed the constructor call in the XAML:

<x:Code><![CDATA[ public MyClass() { InitializeComponent(); }]]></x:Code>

Eric