CODEWITHSUNDEEP
xamldatatrigger
WiiMaxx
WiiMaxx

Reputation: 5420

DataTrigger doesn't swap back

basically i have 2 ComboBoxes and i want to isEnabled="false" my secound ComboBoxe2 as long as my first ComboBoxe1.Selecteditem == null

so i created the following DataTrigger 

    <ComboBox Name="CB1"
              DisplayMemberPath="NameL"
              IsEnabled="{Binding isNew}"
              SelectedItem="{Binding selectedSpTyp}" 
              ItemsSource="{Binding SpTypList}"/>

    <ComboBox Name="CB2"
              DisplayMemberPath="NameD"
              SelectedItem="{Binding selectedDesginvorlage}"
              ItemsSource="{Binding DesginvorlageList}">
        <ComboBox.Style>
            <Style>
                <Setter Property="UIElement.IsEnabled" Value="True"/>
                <Style.Triggers>
                    <DataTrigger Binding="{Binding CB1.SelectedItem, UpdateSourceTrigger=PropertyChanged}" Value="{x:Null}">
                        <Setter Property="UIElement.IsEnabled" Value="False"/>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </ComboBox.Style>
    </ComboBox>

Upvotes: 0

Views: 32

Answers (1)

John Bowen
John Bowen

Reputation: 24453

The Binding in your DataTrigger isn't set up correctly. You've assigned the Binding a Path of CB1.SelectedItem so it is looking at whatever the current DataContext is for a property named CB1 and then a SelectedItem property on that object. You've also included an UpdateSourceTrigger setting which, while not breaking anything, is meaningless in this instance (it is used to determine when to push changes to the Source with a TwoWay or OneWayToSource binding usually on an input control).

To bind to another control within the same namescope use ElementName to specify the control and Path to specify the property:

<DataTrigger Binding="{Binding ElementName=CB1, Path=SelectedItem}" Value="{x:Null}">

Upvotes: 1

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