Question

I have a WPF ComboBox which is databound to a Collection, but depending on wether a Checkbox is checked or not I’d like to vary which Collection the ComboBox is bound to.

The basic issue is I have a large collection of MyCustomer and I also have a filtered collection of MyCustomer – the filtering is quite intensive and I don’t want to do it with a CollectionView for the main reason that it is already done, the filtered collection already exists – hence the need to simply switch the databinding of the combo.

I’m hoping for a pure XAML solution, obviously writing some code behind would be a relatively simple solutions but it doesn’t feel like it should be required.

Answer 1

Here’s an example using a DataTrigger to switch the collections:

<StackPanel xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'             xmlns:sys='clr-namespace:System;assembly=mscorlib'             xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>     <StackPanel.Resources>         <x:Array x:Key='notes' Type='{x:Type sys:String}'>             <sys:String>do</sys:String>             <sys:String>re</sys:String>             <sys:String>mi</sys:String>         </x:Array>         <x:Array x:Key='letters' Type='{x:Type sys:Char}'>             <sys:Char>a</sys:Char>             <sys:Char>b</sys:Char>             <sys:Char>c</sys:Char>         </x:Array>     </StackPanel.Resources>      <CheckBox x:Name='chkLetters' Content='Use Letters'/>     <ListBox>         <ListBox.Style>             <Style TargetType='{x:Type ListBox}'>                 <Setter Property='ItemsSource' Value='{StaticResource notes}'/>                 <Style.Triggers>                     <DataTrigger Binding='{Binding IsChecked, ElementName=chkLetters}' Value='True'>                         <Setter Property='ItemsSource' Value='{StaticResource letters}'/>                     </DataTrigger>                  </Style.Triggers>             </Style>         </ListBox.Style>     </ListBox> </StackPanel> 

For you these wouldn’t be different arrays, but probably different CollectionViewSources with filters or something, but the principle is the same.