How to set a MenuItem's IsChecked property for a child of type Enum via XAML?

Question

I've bound a MenuItem to a Enum using this solution.

The Enum Values are displayed correctly, yet I cannot seem to set a default checked value for the MenuItem's children items.

Alternatively put, I would like the MenuItem to have one of its children items (the values of the enum I'm using) checked per default.

I've tried the following code, using a Style and a triggered Setter :

<ContextMenu>
  <MenuItem Header="Some Setting" Name="SomeSettingMenu" DataContext="{Binding}" 
            ItemsSource="{Binding Source={StaticResource DisplayTypeValues}}" 
            Click="SomeSettingClicked">                          

    <MenuItem.ItemContainerStyle>
      <Style TargetType="MenuItem">
        <Setter Property="MenuItem.IsCheckable" Value="True"/>

        <Style.Triggers>
          <Trigger Property="MenuItem.Header" Value="enums:AnEnum.ItemA" >
            <Setter Property="MenuItem.IsChecked" Value="True"/>
          </Trigger>
        </Style.Triggers>

      </Style>                            
    </MenuItem.ItemContainerStyle>

  </MenuItem>
</ContextMenu>

The enum contains values such as ItemA, I've also tried AnEnum.First or 0 in the Trigger Value attribute (as answered here), to no avail.

Would a DataTrigger be advisable ? If so, how can I write that in XAML ? Or should I use an DataTemplate within an ItemTemplate for the MenuItem ?

I've also tried fiddling around in code-behind with SomeSetting.Items -related methods, yet most of the properties (such as Current) are read-only.

I am aware that you can write SomeSettingMenu.ItemsSource = Enum.GetValues(typeof(....)) in code-behind, but yet again I don't know how to select an Item within the MenuItem programmatically.

I've also tried this code, doesn't work as well :

<Style.Triggers>
  <DataTrigger Binding="{Binding Path=Header}" Value="enums:DisplayType.ItemA">
    <Setter Property="IsChecked" Value="True" />
  </DataTrigger>                 
</Style.Triggers>

enums is a namespace from a different assembly I'm using.

Any thoughts would be appreciated, thank you in advance !

I've found this article (http://neilmosafi.blogspot.com/2007/08/feb-07-using-combobox-to-select-enum.html) yet when I try to adapt it for my MenuItem a nice looking Exception is thrown. Any thoughts ? — Dr1Ku, Dec 01 '10 at 12:39

Fredrik Hedblad · Answer 1 · 2010-12-02T09:57:49.137

You can do this. This will Bind to the child MenuItem's DataContext, which is "ItemA" for the first item.

<MenuItem.ItemContainerStyle> 
    <Style TargetType="MenuItem">
        <Setter Property="MenuItem.IsCheckable" Value="True"/>
        <Style.Triggers> 
            <DataTrigger Binding="{Binding}" Value="ItemA">
                <Setter Property="MenuItem.IsChecked" Value="True"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</MenuItem.ItemContainerStyle>

score 2 · Accepted Answer · answered Dec 01 '10 at 15:50

2

in your solution consider changing

<Trigger Property="MenuItem.Header" Value="enums:AnEnum.ItemA" >

to

<Trigger Property="MenuItem.Header" Value="{x:Static enums:AnEnum.ItemA}" >

in your example you check that header is equal to sting "enums:AnEnum.ItemA" not to enum AnEnum member ItemA.

answered Dec 01 '10 at 15:50

The Smallest

5,713
25
38

That sounds like really good news, I'll check it out and let you know, thank your for your input on this question as well ! – Dr1Ku Dec 01 '10 at 17:05

How to set a MenuItem's IsChecked property for a child of type Enum via XAML?

2 Answers2

Linked