Binding usercontrol property to custom class

Question

In my application I\'m using a usercontrol called \"ChannelControls\" which I instance 6 times, on the mainwindow.

public partial class Channel         


        

Answer 1

A UserControl should never have an "own" instance of a view model. Instead, it should have dependency properties that are bound to properties of an "external" view model.

Your ChannelsControl would declare a property like this (where I suppose that string is not an appropriate type for a count):

public partial class ChannelsControl : UserControl
{
    public static readonly DependencyProperty SpriteCountProperty =
        DependencyProperty.Register(
            nameof(SpriteCount), typeof(string), typeof(ChannelsControl));

    public string SpriteCount
    {
        get { return (string)GetValue(SpriteCountProperty); }
        set { SetValue(SpriteCountProperty, value); }
    }

    ...
}

In ChannelsControl's XAML, you would bind it like this:

<CMiX:Counter Count="{Binding SpriteCount,
                      RelativeSource={RelativeSource AncestorType=UserControl}}"/>

You would now use your UserControl like shown below, where you bind the Count property to a view model in the DataContext like this:

<Window.DataContext>
    <local:CMiXData />
</Window.DataContext>
...

<local:ChannelsControl SpriteCount="{Binding SpriteCount[0]}" ... />

---

You may now also use ChannelsControl in the ItemTemplate of an ItemsControl like this:

<ItemsControl ItemsSource="{Binding SpriteCount}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <local:ChannelsControl SpriteCount="{Binding}"/>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

---

EDIT: Set the Window's DataContext to your view model singleton instance like this:

<Window ... DataContext="{x:Static local:CMiXData.Instance}" >

Or in code behind, in the MainWindow constructor:

DataContext = CMiXData.Instance;