Menus and MVVM

[Corrado Cavalli]

Any chance to have a Command property on RadMenuItem? that would help M-V-VM development a lot.

Thanks
Corrado

[Valeri Hristov]

Hello Corrado,

There is no ICommandSource interface in Silverlight, yet, hence RadMenuItem does not have a Command/CommandParameter/CommandTarget properties.

On the other hand, we provide our own implementation for routed commands, that include the interface, but it was first intended only for internal use and that's why most of the controls do not implement it. I am currently updating RadMenuItem and most probably it will get the Command property with the internal build next week.

Greetings,
Valeri Hristov
the Telerik team

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[Neal Sanche]

Any updates on this since? I would also love to be able to bind ICommand to a property on the RadContextMenu. In the meantime I am trying to wire up an attached behavior, but I'm not quite sure how that's going to work yet.

-Neal

[Valeri Hristov]

Hi Neal,

RadMenu/RadContextMenu for Silverlight and WPF will provide ICommandSource implementation as of Q3 2009 which will be released this week.

Regards,
Valeri Hristov
the Telerik team

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[Neal Sanche]

Thanks! That's great, I can hardly wait.

-Neal

[Neal Sanche]

Just a follow-up. I have upgraded to the Q3 release and have tried doing a binding with a RadMenuItem using its Command property to a property on my ViewModel class (of type ICommand) and it works! This is a great new feature of the Q3 release, and isn't mentioned very much in the release notes (on my initial skim of them).

Here's my XAML:

<Grid Height="39" MinWidth="90">
   <Controls:RadContextMenu.ContextMenu>
      <Controls:RadContextMenu>
         <Controls:RadMenuItem Command="{Binding DeleteQueryCommand}" Header="Delete Query"/>
      </Controls:RadContextMenu>
   </Controls:RadContextMenu.ContextMenu>
   <TextBlock Text="Query 1"/>
</Grid>

I've been following a DelegateCommand pattern in my view model classes, and the code for this command looks something like the following:

        #region DeleteQuery Command

        private DelegateCommand m_deleteQueryCommand;

        public ICommand DeleteQueryCommand
        {
            get
            {
                if (m_deleteQueryCommand == null) m_deleteQueryCommand = new DelegateCommand(DeleteQuery, DeleteQueryCanExecute);
                return m_deleteQueryCommand;
            }
        }

        private void DeleteQueryCanExecuteChanged()
        {
            m_deleteQueryCommand.RaiseCanExecuteChanged();
        }

        private bool DeleteQueryCanExecute()
        {
            return true;
        }

        private void DeleteQuery()
        {
            QueryDeleted.Fire(this, EventArgs.Empty);
        }

        #endregion

I've even tested that the menu item is grayed out when the DeleteQueryCanExecute method returns false!

Thanks for the great work!

-Neal

[Kevin Finke]

This is exactly what I want!

But where oh where is the rest of the command framework?  Where is DelegateCommand defined?  I seem to be missing something!

[Valeri Hristov]

Hi Kevin,

Our command framework was designed to be used the same way as the standard WPF commands, hence there is no delegate commands, etc. It was first developed to provide a compatibility layer for the RadScheduler port to Silverlight, later we began using it in other controls. The ICommandSource implementation in RadMenuItem is standard and will work with any command framework, such as Prism for example.

Sincerely yours,
Valeri Hristov
the Telerik team

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[bohebolo]

Is it possible to use command with dynamic data binding on RadMenu?
And if yes, how to do that?

[bohebolo]

I've got the answer now, and yes it can actually.
Just bind Command & CommandParameter properties in ContainerBindingCollection.
EDIT: layoutRoot is a grid in my view which it's datacontext is bound to my viewmodel.

<telerik:HierarchicalDataTemplate x:Key="mainMenuTemplate" ItemsSource="{Binding SubItems}">

    <telerik:ContainerBinding.ContainerBindings>

        <telerik:ContainerBindingCollection>

            <telerik:ContainerBinding PropertyName="Icon" Binding="{Binding Icon}" />

            <telerik:ContainerBinding PropertyName="Command" Binding="{Binding
                      DataContext.MenuOpenCommand, ElementName=layoutRoot, Mode=OneWay}" />

            <telerik:ContainerBinding PropertyName="CommandParameter" Binding="{Binding}" />

        </telerik:ContainerBindingCollection>

    </telerik:ContainerBinding.ContainerBindings>

    <TextBlock Text="{Binding Text}" />

</telerik:HierarchicalDataTemplate>

[Kaloyan]

Hello bohe,

The approach taken is the correct one. Let us know if you are facing any further issues.

Kind regards,
Kaloyan
the Telerik team

[Hicham]

Hi,
I wanna send a commandParameter to a command, but i get always null for the parameter:

 <telerik:RadContextMenu.ContextMenu>
                                <telerik:RadContextMenu>
                                    <telerik:RadContextMenu.Items>
                                        <telerik:RadMenuItem Header="Fonctions Mathématiques"  >
                                            <telerik:RadMenuItem Header="INT()" Command="{Binding TestCommand}" CommandParameter="{Binding ElementName=txtFormula}"/>
                                            <telerik:RadMenuItem Header="AVERAGE()" />
                                            <telerik:RadMenuItem Header="ROUND()" />
                                            <telerik:RadMenuItem Header="ROUNDUP()" />
                                            <telerik:RadMenuItem Header="ROUNDDOWN()" />
                                        </telerik:RadMenuItem>
                                        <telerik:RadMenuItem Header="Operateurs" >
                                            <telerik:RadMenuItem Header="&lt;" />
                                            <telerik:RadMenuItem Header="&gt;" />
                                            <telerik:RadMenuItem Header="&lt;&gt;" />
                                        </telerik:RadMenuItem>
                                    </telerik:RadContextMenu.Items>
                                </telerik:RadContextMenu>
                            </telerik:RadContextMenu.ContextMenu>

the command :

 string testCommand = "";
        public ICommand TestCommand
        {
            get
            {
                return new RelayCommand<System.Windows.Controls.RichTextBox>((o) =>
                {
                    if (o != null)
                        testCommand = o.ExtentWidth.ToString();
 
 
                    
                });
            }
        }

do you have any idea about this issue?

thanks.