Binding to the Items properties of an ItemsControl - wpf

Question

I'm looking to a way to bind a Button Text or IsEnabled property for example to the IsChecked property in an ItemsControl
Here is my simplified source code :
<StackPanel>
<ItemsControl ItemsSource="{Binding Tasks}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Margin="10,0,10,0" Text="{Binding Name}"/>
<CheckBox IsChecked="{Binding InProgress}"/>
<CheckBox IsChecked="{Binding Done}"/>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<Button/>
</StackPanel>
I would like (for example) if all the "Done" CheckBoxes are Checked, to set Button Text to some value or to enable it. I thought doing this with Data Binding in Xaml using DataTriggers but I don't know how to do it.
Ca anyone give me a full xaml solution ?

Answer 1

New Answer
Sorry, I misunderstood the question. I would expose another property from your DataContext that simply returns true/false if all the items in the collection are checked or not, and base your Button's Text/IsEnabled off that property using a DataTrigger
<Style TargetType="{x:Type Button}">
<Setter Property="IsEnabled" Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding IsAllChecked}" Value="True">
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
Old Answer
DataTriggers simply take a binding, and check if the result is equal to some value.
<Style TargetType="{x:Type TextBox}">
<Setter Property="IsEnabled" Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding Done}" Value="True">
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
If you need to test more than one condition, you need a MultiDataTrigger
<Style TargetType="{x:Type TextBox}">
<Setter Property="IsEnabled" Value="False" />
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding Path=InProgress}" Value="True" />
<Condition Binding="{Binding Path=Done}" Value="True" />
</MultiDataTrigger.Conditions>
<Setter Property="IsEnabled" Value="True" />
</MultiDataTrigger>
</Style.Triggers>
</Style>
Note that the default value of setter is part of the style. This is important because if you set the default value on the <TextBox> then it has a higher priority than triggered values, so triggered values are unable to change the current value.

Answer 2

You can change this line...
<Button/>
To this
<Button Content={Binding ButtonContent}/>
And set the 'ButtonContent' property in your ViewModel whenever your 'Done' check box gets checked.

Answer 3

Usually, the best way to do that is to synthesize the state you want to apply to your button into a property of your ViewModel.
The WPFy way in that case is for your ViewModel to expose a command that implements the action of your button.
The command in turns can react to changes in your data to signal if it is available or not, and thus will automaticaally disable/enable your button. An added bonus is that you can easily implement a menu for example, that will be properly enabled/disabled at no cost once you have your command.
It's been a long time since I had any chance to touch WPF, so I do not have any really useful links at hand, but if I were you I would learn about commands in WPF, they are a very important part of the MVVM architecture.