Using Rx with MVVM pattern

[Kenneth Haugland]

I have a canvas which I hook to the ViewModel:

With the ViewModel:

class MainViewModel
{
public MainViewModel()
{
this.MouseDown = new DelegateCommand(
this.OnMouseDown, this.CanMouseDown);
}

    public ICommand MouseDown { get; private set; }

    private void OnMouseDown(object arg)
    {
    //Do Something
    }
    private bool CanMouseDown(object arg) { return true; }
}

But I really don't need all these details, I just need the positions received:

var MouseDownPosition = from evt in Observable.FromEventPattern(
h => cnvMainView.MouseDown += h,
h => cnvMainView.MouseDown -= h)
select evt.EventArgs.GetPosition(cnvMainView);

So how do people hook the Rx observables to the ViewModel?

[Kenneth Haugland]

I gave up on the Rx part and did my own EventCommand:

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Interactivity;

namespace WpfSimpleReflectionAssistant
{
//Code from:
//https://social.msdn.microsoft.com/Forums/silverlight/en-US/5cd586e7-640f-447b-9040-e9270173abf7/passing-drop-event-data-in-a-command-parameter-using-mvvm-and-the-interactivity-framework?forum=silverlightmvvm
public sealed class EventCommand : TriggerAction
{

    public static readonly DependencyProperty CommandParameterProperty =
        DependencyProperty.Register("CommandParameter", typeof(object), typeof(EventCommand), null);


    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register(
        "Command", typeof(ICommand), typeof(EventCommand), null);


    public static readonly DependencyProperty InvokeParameterProperty = DependencyProperty.Register(
        "InvokeParameter", typeof(object), typeof(EventCommand), null);

    private string commandName;

    public object InvokeParameter
    {
        get
        {
            return this.GetValue(InvokeParameterProperty);
        }
        set
        {
            this.SetValue(InvokeParameterProperty, value);
        }
    }


    public ICommand Command
    {
        get
        {
            return (ICommand)this.GetValue(CommandProperty);
        }
        set
        {
            this.SetValue(CommandProperty, value);
        }
    }

    public string CommandName
    {
        get
        {
            return this.commandName;
        }
        set
        {
            if (this.CommandName != value)
            {
                this.commandName = value;
            }
        }
    }

    public object CommandParameter
    {
        get
        {
            return this.GetValue(CommandParameterProperty);
        }

        set
        {
            this.SetValue(CommandParameterProperty, value);
        }
    }

    public object Sender { get; set; }

    protected override void Invoke(object parameter)
    {
        this.InvokeParameter = parameter;
        if (this.AssociatedObject != null)
        {
            ICommand command