Specify Command for MenuItem in a DataTemplate

Question

I have a context menu. It's bound to some collection and it has a defined ItemTemplate like this:

<ContextMenu
    ItemsSource={Binding ...}
    ItemTemplate={StaticResource itemTemplate}
    />

itemTemplate is a simple DataTemplate with a TextBlock:

<DataTemplate x:Key="itemTemplate">
    <TextBlock Text={Binding ...} />
</DataTemplate>

How do I bind Command property for MenuItem to the underlying object's property?

Answer 1

I think you need to wrap your TextBlock in a MenuItem:

<DataTemplate x:Key="itemTemplate">
    <MenuItem Command={Binding ...}>
        <TextBlock Text={Binding ...} />
    </MenuItem>
</DataTemplate>

But I don't have an IDE in front of me right now to try this. Let me know how it goes.

---

Looks like you need to use the ItemContainerStyle as seen here. Sorry for leading you down the wrong path at the start there - but I got in front of an IDE and this works:

<ContextMenu.ItemContainerStyle>
    <Style TargetType="MenuItem">
        <Setter Property="Command" Value="{Binding ...}"/>
    </Style>
</ContextMenu.ItemContainerStyle>

Answer 2

Although this is only a slight variation on Martin Harris's answer, I thought I'd share it anyway. I found it more useful specify a single command for the whole collection and also send along a CommandParameter:

<MenuItem.ItemContainerStyle>
    <Style TargetType="MenuItem">
       <Setter Property="Command" Value="{x:Static v:ViewModel.CommandForAll}"/>
       <Setter Property="CommandParameter" Value="{Binding ValueForCommand}"/>
    </Style>
</MenuItem.ItemContainerStyle>

Then you can determine what to do in the handler for the command:

private void CommandForAll_Executed(object sender, ExecutedRoutedEventArgs e)
{
    var cmdParam = e.Paramater as ExpectedType
    if (cmdParam != null)
        //DoStuff...
}

Answer 3

I realize I'm answering this quite a bit after the fact, but I ran into the same problem and the previous answers seemed to make binding to multiple different commands difficult. The solution I arrived is very similar to MatrixManAtYrService's and works in 3 parts:

1) Bind the command using the ItemContainerStyle property to a command in the ViewModel -- this is the same as the previous answers. One exception is that I bind the CommandParameter to the MenuItem.

<Setter Property="CommandParameter" Value="{Binding RelativeSource={RelativeSource Self}}"/>

2) Create a custom class to define the look and behavior of each MenuItem. The ItemsSource of the menu will be set to a list of these. This is the same as other answers. However, in my implementation I have given the class an Action to be executed when the MenuItemCommand is invoked. I also included a boolean that will allow the MenuItem to be disabled.

public class MenuAction
{
    public string Name { get => name; set => name = value; }
    public Action Action { get => action; set => action = value; }
    public bool CanExecute { get => canExecute; set => canExecute = value; }
}

3) In the command implementation route control to the delegates in MenuAction.

public void HandleCommand(object sender)
{
    MenuItem clickedMenuItem = sender as MenuItem;
    MenuAction menuAction = clickedMenuItem?.DataContext as MenuAction;
    if(menuAction != null)
        menuAction.Action();
}

public bool CanMenuItemExecute(object sender)
{
    MenuItem clickedMenuItem = sender as MenuItem;
    MenuAction menuAction = clickedMenuItem?.DataContext as MenuAction;
    if (menuAction != null)
        return menuAction.CanExecute;
    else
        return false;
}

This should allow you to define all of the behavior of your commands in a list. While it is technically binding to a single command it is functionally similar to having multiple different commands. The same method should also work with nested MenuItems and HierarchicalDataTemplates with some tweaking.