Custom ContentControl in WPF

Question

I think I'm asking for a lecture on the proper application of WPF here but I'm going to take my chances since I'm at my wit's end. I think this is probably largely a result of my lethargy in fully embracing WPF templates and styles so I'm happy to listen to any such lectures.

I'm writing a sort of audio editor / event orchestrator. I've got a track editor that I'm fairly happy with. However, I built it largely out of custom controls (I know, this is probably a WPF sin). In keeping with that theme, I want to make a standard header for the tracks but I want the individual track "types" to be able to define what goes in that header. I thought a control that defines a sort of "grip" on the edge and then allowed the implementer to "fill in" the substance would work well. However, I have no idea how to do this in WPF without using styles and even if I end up using styles, I would like to understand this.

This probably comes down to wanting a sort of exemplar implementation of a simple ContentControl control (e.g. a button) and not being able to find one (other than AvalonDock, which ultimately uses - correctly i'm sure - templates for this). In my head, the xaml looks something like this:

<ContentControl x:Class="TestArea.CustomContentControl2"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="100"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <TextBlock Text="Hello"/>
    <ContentPresenter Grid.Column="1"/>
</Grid>

But of course, that doesn't work. I'm fairly sure I could pull the same thing off by playing tricks with overloads behind the scenes, but it would be nice if I could do something like this. Do I really have to put all my terrible, procedural ways behind me and use these styles you speak of? If so, can someone at least tell me what that button looks like down in the framework?

Answer 1

Here is a complete example of deriving from ContentControl to accomplish what you want: Creating Customized UserControls (Deriving from ContentControl) in WPF 4

Pete's ContentPresenter is doing the same thing as it does in your example.

Answer 2

Using styles allows you to seperate functionality of a control with representation of a control; such as the Button.

Think as a control at the start as nothing more then functionality. A simple class containing predefined events, properties, etc... Once that control takes on the job of becoming part of a visual tree it now needs a visual identity. It didn't need one previously; however now it does. Defining a default style allows that control to now have a visual representation which it did not need prior as it was not living within the visual tree.

Ignoring styles would be like ignoring CSS when making use of HTML.