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I want to bind Viewmodel command to Usercontrol's Routed Event. Here is the detailed explanation of what I have.

I have a User Control which have one Image (which shows image) and one Button at bottom (Button to remove Image). I am using a Usercontrol in a ListView.

In my Usercontrol's Code behind I have a RoutedEventHandler to remove the Image:

public event RoutedEventHandler RemoveImage;

In the window where I use this Usercontrol, I have put:

<uc:ucImageListItem x:Name="ImageListItem" RemoveImage="ImageListItem_RemoveImage"  />

This code works correctly if My code to remove image is in code behind. but I want to Bind command of Viewmodel to RemoveImage RoutedEvent.

Probably like (not correct)

<uc:ucImageListItem x:Name="ImageListItem" RemoveImage="{binding CommandtoRemove}"  />

How to achieve this?

I found something related to RoutedCommand or DependancyProperty, but could not find any proper way, How to use them.

Let me know if I need to further clear my question. Thanks in anticipation.

Dave Clemmer
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Hardik
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  • Do you use any MVVM framework? – Andrey Gordeev Feb 26 '13 at 05:40
  • Yes, I have classical MVVM. – Hardik Feb 26 '13 at 05:42
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    possible duplicate of [WPF event binding from View to ViewModel?](http://stackoverflow.com/questions/7877532/wpf-event-binding-from-view-to-viewmodel) – Emond Feb 26 '13 at 05:42
  • Hi ,I dnt think you can acheive that with MVVM using command until the itemesource are not in VM. i means for removing the image using command you need the image that will be bound to your image control there in VM – yo chauhan Feb 26 '13 at 06:24
  • @ethicallogics, Thanks for your comment, Can you show me the way How to call Command of MVVM, I can do further by another trick, I have. – Hardik Feb 26 '13 at 06:26
  • i have given solution below for invoking command. – yo chauhan Feb 26 '13 at 06:39
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    Hi Hardik, Take a look at [AttachedCommandBehaviors](http://marlongrech.wordpress.com/2008/12/13/attachedcommandbehavior-v2-aka-acb/) it worked for me. – Jordy van Eijk Feb 26 '13 at 09:42

1 Answers1

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Hi this piece of code shows how to call command: Command handler

public class CommandHandler : ICommand
{
    public CommandHandler(Action<object> action,Func<object,bool> canexecute)
    {
        _action = action;
        _canExecute = canexecute;

    }
    Action<object> _action;
    Func<object, bool> _canExecute;

    public bool CanExecute(object parameter)
    {
       return _canExecute(parameter);
    }

    public event EventHandler CanExecuteChanged;

    public void Execute(object parameter)
    {
        _action(parameter);
    }
}

ViewModel

public class MainViewModel
{
    private CommandHandler _buttonCommand;

    public CommandHandler ButtonCommand
    {
        get
        {
            return _buttonCommand ?? (_buttonCommand = new CommandHandler((param) => OnButtonCommand(param),(param)=>true));
        }
    }

    private void OnButtonCommand(object obj)
    {
        //DO things here whatever you want to do on Button click
    } 
}

View

<Button Command="{Binding ButtonCommand}" Content="ok"/>

you need to pass two parameters to CommandHandler Constructor one is Action that you want to fire on Command and second param is func that must return bool. If func evaluates to true only then the Action of Command is fired.And the param in action and func is what you will bind to the CommandParameter in my case above it will be null as I havent binded the CommandParameter.I hope this will help.

yo chauhan
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  • Thanks for Post, I need command to be bound to Custom RoutedEvent of Usercontrol, ie. I need command to be called when 'RemoveImage' custom event is invoked. – Hardik Feb 26 '13 at 06:49
  • You have event in .cs you have handler in .cs then why you want it to handle through Command.Search for Relay Commands on net they let you to bind the event to VM through Command.but for that u will have the handler in VM. – yo chauhan Feb 26 '13 at 07:03