== Using Ribbon UI with WPF ==
 # Create new VB 2008 WPF application.
 # Add reference to ''RibbonControlLibrary.dll''
 # Place a ''Ribbon''.
 # Select the ''Ribbon'', click the "..." by Tabs. Add a Tab.
 # In the added tabs properties, press the "..." button by the Groups property.
 # Add a Group.

Solved the unhandled exception by adding a ''GroupSizeDefinition'' in the ''RibbonGroup'' :
<code xml>
<my:RibbonGroup Name="Group1" HasDialogLauncher="True" Command="{StaticResource Group1Command}">
  <my:RibbonGroup.GroupSizeDefinitions>
    <my:RibbonGroupSizeDefinitionCollection >
    <my:RibbonGroupSizeDefinition>
      <my:RibbonControlSizeDefinition ImageSize="Large" IsLabelVisible="True" />
      <my:RibbonControlSizeDefinition ImageSize="Small" IsLabelVisible="True" />
      <my:RibbonControlSizeDefinition ImageSize="Small" IsLabelVisible="True" />
      <my:RibbonControlSizeDefinition ImageSize="Small" IsLabelVisible="True" />
    </my:RibbonGroupSizeDefinition>
  </my:RibbonGroupSizeDefinitionCollection>
  </my:RibbonGroup.GroupSizeDefinitions>
</my:RibbonGroup>
</code>

Full ''Window1.xaml'' listing:
<code xml>
<r:RibbonWindow
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:r="clr-namespace:Microsoft.Windows.Controls.Ribbon;assembly=RibbonControlsLibrary"
    x:Class="RibbonTutorial.Window1"
    x:Name="Window"
    Title="Window1"
    Width="640" Height="480">

    <Grid x:Name="LayoutRoot">
        <r:Ribbon Title="ezFIT - Prototype (Ribbon UI)" x:Name="ribbon">
            <r:Ribbon.Resources>
                <r:RibbonCommand x:Key="SaveCommand"
                           CanExecute="SaveCommand_CanExecute"
                           Executed="SaveCommand_Executed"
                           LabelTitle="Save"
                           SmallImageSource="images\Clear.png"
                           LargeImageSource="images\Delete.png"
                           ToolTipTitle="Save"
                           ToolTipDescription="Save your work." />
            </r:Ribbon.Resources>
            <r:RibbonTab Label="Patient">
                <r:RibbonGroup Name="Group1" 
                          HasDialogLauncher="True" 
                          Command="{StaticResource SaveCommand}" >
                    <r:RibbonGroup.GroupSizeDefinitions>
                        <r:RibbonGroupSizeDefinitionCollection >
                            <r:RibbonGroupSizeDefinition>
                                <r:RibbonControlSizeDefinition ImageSize="Large" IsLabelVisible="True" />
                                <r:RibbonControlSizeDefinition ImageSize="Small" IsLabelVisible="True" />
                                <r:RibbonControlSizeDefinition ImageSize="Small" IsLabelVisible="True" />
                                <r:RibbonControlSizeDefinition ImageSize="Small" IsLabelVisible="True" />
                            </r:RibbonGroupSizeDefinition>
                        </r:RibbonGroupSizeDefinitionCollection>
                    </r:RibbonGroup.GroupSizeDefinitions>
                </r:RibbonGroup>
            </r:RibbonTab>
            <r:RibbonTab Label="Product List"/>
            <r:RibbonTab Label="Fitting"/>
            <r:RibbonTab Label="Reports"/>
        </r:Ribbon>
    </Grid>
</r:RibbonWindow>
</code>
== References ==
 * [[http://windowsclient.net/wpf/wpf35/wpf-35sp1-ribbon-walkthrough.aspx#commands|WPF Ribbon Inside Out]]
 * [[http://www.uxpassion.com/2009/02/how-to-use-add-ribbon-to-wpf-applications-part-5/|How to add a Ribbon to WPF applications]]
 * [[http://www.codeplex.com/wpf/WorkItem/View.aspx?WorkItemId=9361|Unhandled exception when adding a Ribbon Group to a Ribbon Tab]]