PropertyChanged event on viewmodel property - wpf

Question

i'm trying to Raise a PropertyChanged event on a Property in my ViewModel
using interaction triggers .
CS :
public string MyContentProperty
{
get { return "I Was Raised From an outside Source !";}
}
XAML :
<Button Content="{Binding MyContentProperty}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Button.Click">
< .... what needs to be done ?>
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
of course if there was any doubt for this question you have references to
xmlns:ei="clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
at your disposal , thanks in advance .

Answer 1

You can use a normal command or Expression Blend's CallMethodAction, InvokeCommandAction or ChangePropertyAction.
Here are four ways to do what you want:
<Button Content="Button" Height="23" Width="100" Command="{Binding RaiseItCmd}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<i:InvokeCommandAction Command="{Binding RaiseItCmd}"/>
<ei:CallMethodAction MethodName="RaiseIt" TargetObject="{Binding}"/>
<ei:ChangePropertyAction Value=""
PropertyName="MyContentProperty" TargetObject="{Binding}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
Here I'm using MVVM Light's ViewModelBase:
using System.Windows.Input;
using GalaSoft.MvvmLight;
using Microsoft.Expression.Interactivity.Core;
public class ViewModel : ViewModelBase
{
public ViewModel()
{
RaiseItCmd = new ActionCommand(this.RaiseIt);
}
public string MyContentProperty
{
get
{
return "property";
}
set
{
this.RaiseIt();
}
}
public void RaiseIt()
{
RaisePropertyChanged("MyContentProperty");
}
public ICommand RaiseItCmd { get; private set; }
}