how to pass argument to the method present in event trigger wpf

Question

Actually, I'm trying to pass the name of the word document in the method UpdateWord(object obj) present in the ViewModel of the Xaml file. So that it will open the word document.

<Button Content="Show Word" Width="100" Height="25" Margin="128,70,22,37">
    <i:Interaction.Triggers>
            <i:EventTrigger EventName="Click">
                <si:CallDataMethod Method="UpdateWord"/>     
                <si:SetProperty TargetName="LayoutRoot" 
        PropertyName="Background" Value="PaleGoldenrod"/>
     </i:EventTrigger>
  </i:Interaction.Triggers>          

ViewModel :

public void UpdateWord(Object obj)
{

   //Do Something ..... ;
}

Answer 1

you can do like this

  <i:EventTrigger EventName="Click">
        <cmd:EventToCommand Command="{Binding UpdateWord}"
            PassEventArgsToCommand="True" />
    </i:EventTrigger>

you can refer this post for more deatil : http://weblogs.asp.net/alexeyzakharov/silverlight-commands-hacks-passing-eventargs-as-commandparameter-to-delegatecommand-triggered-by-eventtrigger

Answer 2

There are multiple ways of doing this, look here:

1. Using WPF Tools. Easiest

Add Namespaces:

• System.Windows.Interactivitiy
• Microsoft.Expression.Interactions

XAML:

<Window>
    xmlns:wi="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
    xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions">

    <wi:Interaction.Triggers>
        <wi:EventTrigger EventName="SelectionChanged">
            <ei:CallMethodAction
                TargetObject="{Binding}"
                MethodName="ShowCustomer"/>
        </wi:EventTrigger>
    </wi:Interaction.Triggers>
</Window>

Code:

public void ShowCustomer()
{
    // Do something.
}

2. Using MVVMLight. Most difficult but best practice

Install GalaSoft NuGet package.

Get the namespaces:

• System.Windows.Interactivity
• GalaSoft.MvvmLight.Platform

XAML

<Window>
    xmlns:wi="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
    xmlns:cmd="http://www.galasoft.ch/mvvmlight">

    <wi:Interaction.Triggers>
       <wi:EventTrigger EventName="Navigated">
           <cmd:EventToCommand Command="{Binding NavigatedEvent}"
               PassEventArgsToCommand="True" />
       </wi:EventTrigger>
    </wi:Interaction.Triggers>
</Window>

Code With Delegates: Source

You must get the Prism MVVM NuGet package for this.

using Microsoft.Practices.Prism.Commands;

// With params.
public DelegateCommand<string> CommandOne { get; set; }
// Without params.
public DelegateCommand CommandTwo { get; set; }

public MainWindow()
{
    InitializeComponent();

    // Must initialize the DelegateCommands here.
    CommandOne = new DelegateCommand<string>(executeCommandOne);
    CommandTwo = new DelegateCommand(executeCommandTwo);
}

private void executeCommandOne(string param)
{
    // Do something here.
}

private void executeCommandTwo()
{
    // Do something here.
}

Code Without DelegateCommand: Source

using GalaSoft.MvvmLight.CommandWpf

public MainWindow()
{
    InitializeComponent();

    CommandOne = new RelayCommand<string>(executeCommandOne);
    CommandTwo = new RelayCommand(executeCommandTwo);
}

public RelayCommand<string> CommandOne { get; set; }

public RelayCommand CommandTwo { get; set; }

private void executeCommandOne(string param)
{
    // Do something here.
}

private void executeCommandTwo()
{
    // Do something here.
}

3. Using Telerik EventToCommandBehavior. You'll have to download it's NuGet Package. It's an option.

XAML:

<i:Interaction.Behaviors>
    <telerek:EventToCommandBehavior
         Command="{Binding DropCommand}"
         Event="Drop"
         PassArguments="True" />
</i:Interaction.Behaviors>

Code:

public ActionCommand<DragEventArgs> DropCommand { get; private set; }

this.DropCommand = new ActionCommand<DragEventArgs>(OnDrop);

private void OnDrop(DragEventArgs e)
{
    // Do Something
}