How to add UserControl to a Panel on a WPF Window - wpf

Question

I think I'm missing something that should be obvious here, but I'm drawing a blank on this one.
I've built a very primitive UserControl containing nothing more than a TextBox to use as a log window:
<UserControl x:Class="My.LoggerControl"
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"
x:Name="LoggerView">
<Grid x:Name="LayoutRoot">
<TextBox x:Name="LogWindow" AcceptsReturn="True"/>
</Grid>
</UserControl>
I don't expect that to be the best way to do it, but it should be good enough for a prototype.
The code-behind is similarly simple:
public partial class LoggerControl : UserControl, ILogger
{
public LoggerControl()
{
InitializeComponent();
}
private LogLevel level = LogLevel.Warning;
#region ILogger
public LogLevel Level
{
get { return level; }
set { level = value; }
}
public void OnError(string s)
{
if (level >= LogLevel.Error)
LogWindow.AppendText("ERROR:::" + s + "\n");
}
// ...
#endregion
}
The thing I can't figure out is how to add this control to my MainWindow.xaml. Simplifying, lets say my window looks like this:
<Window x:Class="My.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:My"
Title="Test" Height="350" Width="525">
<Grid>
<local:LoggerControl x:Name="LogView" />
</Grid>
</Window>
Even with something so simple, the Designer in Visual Studio 2010 can't load the main window. The error given is:
A value of type 'LoggerControl' cannot be added to a collectionor dictionary of type 'UIElementCollection'.
This error message has only one unrelated hit in the major search engines (plus duplicates) so I haven't found any useful help. Microsoft's own documentation seems to imply that this should work.
Any idea how to solve this?

Answer 1

<UserControl x:Class="My.LoggerControl"
xmlns:local="clr-namespace:My.LogTest"
Looks like you may have made a mistake in the namespacing? LoggerControl is listed as being the namespace My, while you're importing My.LogTest and assigning it to the xml-prefix local. Change this to:
xmlns:local="clr-namespace:My"
And I think it should work. Otherwise, fix the LoggerControl declaration.