Silverlight Error: AG_E_UNKNOWN_ERROR

Question

Hi

I'm getting a AG_E_UNKNOWN_ERROR when running my Silverlight project. The project is ported from WPF, and from what I can gather around the web, I'd assume it's related to something invalid in my XAML

EDIT C# Control sources can be found here: SilverlightCalendar/Controls

Here's Generic.xaml, the styles for my application.

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:c="clr-namespace:SilverlightCalendar.Controls">

    <Style TargetType="{c:CalendarTimeslotItem}">
        <Setter Property="Content" Value="{Binding}" />
        <Setter Property="Background" Value="White" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{c:CalendarTimeslotItem}">
                    <Border Background="{TemplateBinding Background}"
                            BorderBrush="#A5BFE1"
                            BorderThickness="0,0.5,0,0.5"
                            x:Name="bd"
                            Height="22">
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Style TargetType="{c:CalendarLedgerItem}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{c:CalendarLedgerItem}">
                    <Border Background="#E3EFFF"
                            BorderBrush="#6593CF"
                            BorderThickness="0,0,1,1"
                            Height="44" Width="50">
                        <StackPanel Orientation="Horizontal" 
                                    VerticalAlignment="Center" 
                                    HorizontalAlignment="Center">
                            <TextBlock Text="{TemplateBinding TimeslotA}" 
                                       Foreground="#9493CF" FontSize="16" Margin="0,3,0,0"/>
                            <TextBlock Text="{TemplateBinding TimeslotB}" 
                                       Foreground="#9493CF"  Margin="1.5,0,0,0"/>
                        </StackPanel>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Style TargetType="{c:CalendarDay}">
        <Setter Property="ItemsPanel">
            <Setter.Value>
                <ItemsPanelTemplate>
                    <c:TimeslotPanel />
                </ItemsPanelTemplate>
            </Setter.Value>
        </Setter>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{c:CalendarDay}">
                    <Border Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}">
                        <Grid>
                            <StackPanel x:Name="PART_CalendarTimeslots" />
                            <ItemsPresenter />
                        </Grid>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Style TargetType="{c:CalendarLedger}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{c:CalendarLedger}">
                    <Border Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}">
                        <StackPanel x:Name="PART_CalendarLedgerItems" />
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Style TargetType="{c:Calendar}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{c:Calendar}">
                    <Border Background="#E3EFFF"
                            BorderBrush="#6593CF"
                            BorderThickness="2,2,2,2">
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="50" />
                                <ColumnDefinition Width="*" />
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="*" />
                            </Grid.RowDefinitions>
                            <Border BorderBrush="#6593CF" BorderThickness="0,0,0,1" 
                                    Grid.Column="0" Grid.Row="1" />
                            <Border BorderBrush="#6593CF" BorderThickness="0,0,0,1" 
                                    Grid.Column="1" Grid.Row="1" />
                            <ScrollViewer Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="2">
                                <Grid>
                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition Width="50" />
                                        <ColumnDefinition Width="*" />
                                    </Grid.ColumnDefinitions>

                                    <c:CalendarLedger Grid.Column="0" />
                                    <c:CalendarDay Grid.Column="1" x:Name="PART_CalendarDay" />
                                </Grid>
                            </ScrollViewer>
                        </Grid>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Style TargetType="{c:CalendarAppointmentItem}">
        <Setter Property="StartTime" Value="{Binding StartTime}" />
        <Setter Property="EndTime" Value="{Binding EndTime}" />
        <Setter Property="Width" Value="{Binding ActualWidth, ElementName=CalendarTimeslots}" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{c:CalendarAppointmentItem}">
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="300" />
                            <ColumnDefinition Width="300" />
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="*" />
                        </Grid.RowDefinitions>
                        <Border Grid.Row="0" 
                                Grid.Column="{Binding Column}" 
                                Grid.ColumnSpan="{Binding ColumnSpan}"
                                CornerRadius="4,4,4,4" 
                                BorderThickness="1,1,1,1" 
                                BorderBrush="#5D8CC9" 
                                Background="{Binding Background}"
                                Margin="1,1,5,1" 
                                Padding="5,5,5,5">
                            <Border.Effect>
                                <DropShadowEffect Opacity="0.5" />
                            </Border.Effect>
                            <TextBlock 
                                IsHitTestVisible="False"
                                Foreground="{Binding Foreground}"
                                VerticalAlignment="Top"
                                MaxHeight="20"
                                LineHeight="20"
                                FontFamily="Segoe UI" 
                                FontSize="12.75" 
                                FontWeight="DemiBold"
                                FontStretch="Medium"
                                TextWrapping="WrapWithOverflow"
                                Text="{Binding Subject}" />                            
                        </Border>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

Answer 1

If you look carefully that error usually has a line number which relates to the lines in the XAML.

Answer 2

Recently debugged a bunch of these. When I can't see the problem I just comment big chunk of the XAML until I don't get the error and then uncomment parts until I can find a spot causing the exception.

EDIT: for starters get rid of curly brackets in TargetType="{c:CalendarTimeslotItem}". Just tried and I get the exception this way. Just use TargetType="c:CalendarTimeslotItem"

Answer 3

Configure your system to break when exceptions are thrown.

1. In Visual Studio select the Debug menu, then Exceptions....

2. In the Exceptions dialog box mark the Thrown check box next to Common Language Runtime Exceptions.

3. Start you project in the debugger (make sure that Silverlight debugging is enabled).

You will most likely see some irrelevant exceptions being thrown (just continue debugging) but at one point you should see the offending XAML exception. Inspect the exception to see if you can figure out the line number. If the exception is being thrown in a code-behind file you can infer the XAML file from the code-behind file.

Answer 4

Problem solved (And other arise, but that's for another day)

In my case the use of other bounded properties in the template were causing the issue.

    <Style TargetType="c:CalendarTimeslotItem">
    <!--<Setter Property="Content" Value="{Binding}" />-->
    <Setter Property="Template">

And

    <Style TargetType="c:CalendarAppointmentItem">
    <!--<Setter Property="StartTime" Value="{Binding StartTime}" />-->
    <!--<Setter Property="EndTime" Value="{Binding EndTime}" />-->
    <Setter Property="Template">