Question

I have a ListView Contained in a UserControl I would like to disabled a button when no items are selected in the UserControl, would it be the right way to do it? So far, it doesn’t disable, it just stays enable all the way.
I’ve included the xaml code.

searchAccountUserControl is the UserControl name property in the xaml.
And AccountListView is the ListView name property in the userControl xaml.

<Button Content="Debit" IsEnabled="true" HorizontalAlignment="Left" Margin="18,175,0,0" Name="DebitButton" Width="128" Grid.Column="1" Height="32" VerticalAlignment="Top" Click="DebitButton_Click">
        <Button.Style>
            <Style TargetType="Button">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding ElementName=searchAccountUserControl.AccountListView, Path=SelectedValue}" Value="{x:Null}" >
                        <Setter Property="Button.IsEnabled" Value="false"/>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </Button.Style>
    </Button>

Thanks.

Finally i’ve used :

in my ViewModel :

private bool _isSelected;
public bool IsSelected { get { return _isSelected; } 
set { _isSelected = _account.View.CurrentItem != null;       
PropertyChanged.SetPropertyAndRaiseEvent(this, ref _isSelected, value,  
ReflectionUtility.GetPropertyName(() => IsSelected)); } } 

And then Use isEnabled = “{Binding Path=IsSelected}” in the xaml.

Answer 1

There are a few things wrong here.

1. Precedence, if you set IsEnabled on the control itself the style will never be able to change it.

2. ElementName, it’s an ElementName, not a path, just one string that gives the name of one element. Everything beyond that goes into the Path.

3. Style syntax, if you set a Style.TargetType you should not set the Setter.Property with a type prefix (although leaving it does not break the setter).

By the way, this alone is enough:

<Button IsEnabled="{Binding SelectedItems.Count, ElementName=lv}" ...