All objects added to an IDictionary must have a Key attribute or some other type of key associated with them.- WPF

To fix this compile error... just add a key Ex: x:Key="DummyKey" as below...


<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:sys="clr-namespace:System;assembly=mscorlib">
<sys:DateTime x:Key="DummyKey">10/30/2010 4:30 PM</sys:DateTime>
</ResourceDictionary>

You can also add your own class objects as below..
public class Person
{
string FN { get; set; }
string LN { get; set; }
string MN { get; set; }
}
<Window x:Class="WpfApplication4.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525"
xmlns:local="clr-namespace:WpfApplication4">
<Window.Resources>
<ResourceDictionary>
<local:Person x:Key="testobj" > </local:Person>
</ResourceDictionary>
</Window.Resources>
<Grid>
</Grid>
</Window>