C# WPF XAML Run XAML Command on UserControl load

Question

I am trying to execute a XAML command, when the Usercontrol gets loaded. The reason for that is that i want to change the theme of my application when the user navigates from Usercontrol A to Usercontrol B. I am using Firstfoor ModernUI.

The Code I want to execute:

Command="mui:LinkCommands.NavigateLink"
         CommandParameter="cmd://settheme|/NLauncher;component/designs/ModernUI.BO2ii.xaml"

Usually u execute the Code with a button, but the user navigates with the TabControl included in the ModernUI.

If you have an event you can invoke a command with – ganchito55 Feb 13 '16 at 16:07 — ganchito55, Feb 13 '16 at 16:07
How can I trigger this event with C#? – NemeZiz Feb 13 '16 at 19:54 — NemeZiz, Feb 13 '16 at 19:54

Lionel Pire · Accepted Answer · 2016-02-14T11:29:11.913

3

Make sure you have

xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

In your <UserControl> tag

Then use this piece of code

<i:Interaction.Triggers>
    <i:EventTrigger EventName="Loaded">
        <i:InvokeCommandAction Command="{Binding YourCommand}" CommandParameter = {Binding YourParameter} />
    </i:EventTrigger>
</i:Interaction.Triggers>

You will need to add a reference to System.Windows.Interactivity to your project

Edit : Fixed Event Name Load -> Loaded

edited Feb 14 '16 at 11:29

answered Feb 13 '16 at 19:28

Lionel Pire

338
2
11

How can I trigger this event with C#? – NemeZiz Feb 13 '16 at 19:54
This is the [UserControl.Load](https://msdn.microsoft.com/en-us/library/system.windows.forms.usercontrol.load%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396) event. It is triggered the first time the UserControl is visible as stated on the doc – Lionel Pire Feb 13 '16 at 20:46
Its not working for me, maybe i there is sth missing in my XAML: http://pastebin.com/7GLRP7dH (my complete XAML) – NemeZiz Feb 13 '16 at 21:04
Your XAML seems fine. Maybe try to invoke a command you know will work (Like one that displays something) – Lionel Pire Feb 13 '16 at 22:11
I got it working, the event is "Loaded" not "Load" :) – NemeZiz Feb 14 '16 at 09:27
Oops, my bad, you're right ! Edited for the next person coming here – Lionel Pire Feb 14 '16 at 11:29
Feeling stupid, but where do I have to place it in XAML exactly? in `UserControl.Resources`? – FredM Apr 26 '19 at 11:01

score 0 · Answer 2 · answered May 11 '19 at 07:15

Just added full XAML codes with reference to above answered code of Lionel Pire.

<UserControl x:Class="Test.MyClass"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
             mc:Ignorable="d" 
             d:DesignHeight="450" d:DesignWidth="800"
             >
<Grid  Name="mygrid">

</Grid>


<!--Use this below the grid in case any control is passed in command parameter-->
<i:Interaction.Triggers>
        <i:EventTrigger EventName="Loaded">
            <i:InvokeCommandAction Command="{Binding myCommand}" 
                       CommandParameter = "{Binding ElementName=mygrid}" />
        </i:EventTrigger>
    </i:Interaction.Triggers>
</UserControl>

score 0 · Answer 3 · answered Jan 22 '21 at 17:32

The latest package for XAML Interactions\Interactivity is now published as Microsoft.Xaml.Behaviors.Wpf

Install it via NuGet package manager:

Install-Package Microsoft.Xaml.Behaviors.Wpf

Sample usage:

xmlns:behaviors="http://schemas.microsoft.com/xaml/behaviors"

<Border>
    <behaviors:Interaction.Triggers>
        <behaviors:EventTrigger EventName="Loaded">
            <behaviors:InvokeCommandAction Command="{Binding MyCommand}"/>
        </behaviors:EventTrigger>
    </behaviors:Interaction.Triggers>
</Border>

C# WPF XAML Run XAML Command on UserControl load

3 Answers3