I can't use ActionMessage from caliburn micro, how do I resolve it?

Question

From what I read in the description of Caliburn Micro, this code should be compiled without problems. Caliburn Description

<Button>
<i:Interaction.Triggers>
    <i:EventTrigger EventName="Click">           
        <cal:ActionMessage MethodName="AbrirPDF">
            <cal:Parameter Value="{Binding CNPJ}"/>
        </cal:ActionMessage>            
    </i:EventTrigger>        
</i:Interaction.Triggers>   
</Button>

When trying this, I get the following error:

ArgumentException: Cannot add instance of type 'ActionMessage' to a collection of type 'TriggerActionCollection'. Only items of type 'T' are allowed.

Could someone help me solve this problem?

Answer 1

You probably have the wrong namespace mappings. This should compile:

<UserControl x:Class="CaliburnMicroSample.Views.ShellView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" 
    xmlns:cal="http://www.caliburnproject.org">
    <StackPanel>
        <Button>
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="Click">
                    <cal:ActionMessage MethodName="AbrirPDF">
                        <cal:Parameter Value="{Binding CNPJ}"/>
                    </cal:ActionMessage>
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </Button>
    </StackPanel>
</UserControl>

The only installed NuGet package is Caliburn.Micro 3.2.0.