Question

Its pretty lame, but I tried adding two UserControl‘s to my Silverlight Page, and I get an exception telling me (with extensive digging) that the same control name has been used to the visual tree twice. So the controls inside my UserControl are named, so therefore I can include only one of this UserControl into the Page at a time. Is this true, or am I not realizing something? Has Microsoft truly given up on code-reuse? This is very lame.

Edits

For people who come here, I was getting this a System.Resources.MissingManifestResourceException exception. It took some time to figure out that the problem was ambiguous names in the visual tree. Hopefully this helps you. Below is the full exception text.

Further Edits

Here is my XAML:

<Grid x:Name="LayoutRoot">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>

    <TextBlock x:Name="HeaderText"
        res:Strings.Assignment="Text=MachiningView_Name"/>

    <sdk:TabControl Grid.Row="2">
        <sdk:TabItem Header="Projects">
            <ScrollViewer>
                <Grid>
                    <controls:Organizer Margin="4" ItemsSource="{Binding ProjectSummaries}" Height="24" VerticalAlignment="Top">
                        <controls:Organizer.GroupDescriptions>
                            <controls:OrganizerGroupDescription res:Strings.Assignment="Text=NoGroupingText" IsDefault="True" />
                            <controls:OrganizerGroupDescription res:Strings.Assignment="Text=GroupOwnerEmailText">
                                <controls:OrganizerGroupDescription.GroupDescription>
                                    <helpers:OwnerEmailGroupDescription />
                                </controls:OrganizerGroupDescription.GroupDescription>
                            </controls:OrganizerGroupDescription>
                            <controls:OrganizerGroupDescription res:Strings.Assignment="Text=GroupStoreNumberText">
                                <controls:OrganizerGroupDescription.GroupDescription>
                                    <helpers:StoreNumberGroupDescription />
                                </controls:OrganizerGroupDescription.GroupDescription>
                            </controls:OrganizerGroupDescription>
                        </controls:Organizer.GroupDescriptions>
                    </controls:Organizer>
                </Grid>
            </ScrollViewer>
        </sdk:TabItem>
        <sdk:TabItem Header="Machine Queues">
            <ScrollViewer>
                <Grid>
                    <controls:Organizer Margin="4" ItemsSource="{Binding ProjectSummaries}" Height="24" VerticalAlignment="Top">
                        <controls:Organizer.GroupDescriptions>
                            <controls:OrganizerGroupDescription res:Strings.Assignment="Text=NoGroupingText" IsDefault="True" />
                            <controls:OrganizerGroupDescription res:Strings.Assignment="Text=GroupOwnerEmailText">
                                <controls:OrganizerGroupDescription.GroupDescription>
                                    <helpers:OwnerEmailGroupDescription />
                                </controls:OrganizerGroupDescription.GroupDescription>
                            </controls:OrganizerGroupDescription>
                            <controls:OrganizerGroupDescription res:Strings.Assignment="Text=GroupStoreNumberText">
                                <controls:OrganizerGroupDescription.GroupDescription>
                                    <helpers:StoreNumberGroupDescription />
                                </controls:OrganizerGroupDescription.GroupDescription>
                            </controls:OrganizerGroupDescription>
                        </controls:Organizer.GroupDescriptions>
                    </controls:Organizer>
                </Grid>
            </ScrollViewer>
        </sdk:TabItem>
    </sdk:TabControl>
</Grid>

And here is my user control’s XAML:

<StackPanel Orientation="Horizontal" DataContext="{Binding ElementName=UserControl}">
    <sdk:Label Content="Page:" VerticalAlignment="Center" Margin="0,0,5,0"/>

    <sdk:DataPager Name="_projectSummariesPager"
                   Margin="0,0,5,0"
                   DisplayMode="FirstLastPreviousNextNumeric"
                   Source="{Binding Path=ItemsSource}"
                   PageSize="10"/>

    <ComboBox Name="_itemPerPageCombo"
              Margin="0,0,5,0" 
              SelectionChanged="_itemPerPageCombo_SelectionChanged"
              SelectedItem="{Binding Path=SelectedPageSize, Mode=TwoWay}"
              SelectedValuePath="Value"
              ItemsSource="{Binding Path=PageSizes}"/>

    <ComboBox Name="_groupDescription" 
              Margin="0,0,5,0" 
              SelectionChanged="_groupDescription_SelectionChanged"
              SelectedItem="{Binding Path=SelectedGroupDescription, Mode=TwoWay}"
              ItemsSource="{Binding Path=GroupDescriptions}"/>
</StackPanel>

Answer 1

When you add the UserControl, make sure to assign it a unique name, ie:

<Page ...
    <StackPanel>
         <local:YourUserControl x:Name="Foo" />
         <!-- Make sure not to duplicate x:Name/Name here! -->
         <local:YourUserControl x:Name="Bar" />
    </StackPanel>
</Page>