Type reference cannot find public type named

Question

I am getting error like "Type reference cannot find public type named 'Sign'" in xaml. how can i resolve it. the Sign class is in the same assembly.

<DataTemplate DataType="{x:Type local:Sign}">
    <Expander Padding="4"
              IsExpanded="{Binding RelativeSource={
                    RelativeSource Mode=FindAncestor, AncestorType={
                       x:Type ListBoxItem}}, Path=IsSelected}">
        <Expander.Header>
            <TextBlock Text="{Binding Name}" ... />
        </Expander.Header>
        <DockPanel LastChildFill="True">
            <Border DockPanel.Dock="Left" CornerRadius="16" BorderBrush="WhiteSmoke" Background="AliceBlue" BorderThickness="5" HorizontalAlignment="Center" VerticalAlignment="Center">
                <Image Source="{Binding Icon}" Width="90" Height="90" Stretch="Fill" />
            </Border>
            ...
        </DockPanel>                
    </Expander>

Answer 1

If the type resides in the same assembly as the XAML you are modifying, omit the assembly segment of the clr-namespace when you import the namespace.

DO

xmlns:local="clr-namespace:NamespaceContainingSignClass"

DO NOT

xmlns:local="clr-namespace:NamespaceContainingSignClass;assembly=AssemblyContainingSignClassAndXAML"

Answer 2

For those in my boat who weren't helped by the top 1,00 results for this error on Google....in my case it was the precise opposite of the advice from smelch: i had to ADD the assembly info on the end of my xmlns declaration. Likely because of my particular circumstances, i guess - my datatemplate was in a stand-alone resourcedictionary xaml file. Not sure. I just know it didn't work until i added the assembly info, so for those floundering out there give that a whack and see if it works. i'm not inclined to dive into why, it just did.

Answer 3

1. Check if the root tag of the xaml file has the namespace with class Sign mapped to local alias: xmlns:local="clr-namespace:NamespaceContainingSignClass"
2. Check whether class Sign is marked public
3. Check whether class Sign has parameterless constructor