在 wpf 中绑定多个源元素的依赖属性

Question

Is it possible to bind multiple source to an element's dependecy properties?

In my case, I have a combobox control its ItemSource property filled by a viewmodel, however the Text property is binded to a model which is used by an ItemsControl.

Thank you.

xaml snippet:

<DataTrigger Binding="{Binding EnumType}" Value="6">
<Setter Property="ContentTemplate">
    <Setter.Value>
        <DataTemplate>                
            <ComboBox    
                x:Name="ListOfItems"  
                IsDropDownOpen="{Binding IsDropDownOpen,Mode=OneWay,UpdateSourceTrigger=PropertyChanged}"
                StaysOpenOnEdit="True"
                IsTextSearchEnabled="False"
                IsReadOnly="False"
                IsEditable="True"
                ItemsSource="{Binding Path=FilteredSource,  Source={StaticResource ItemsVM} ,UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}"
                Text="{Binding   Path=Result, UpdateSourceTrigger=PropertyChanged}"                 
                DisplayMemberPath="{Binding  Path=Item.Name,  Source={StaticResource ItemsVM}}" >                 

                <ComboBox.Triggers>
                    <EventTrigger RoutedEvent="TextBoxBase.TextChanged">
                        <BeginStoryboard>
                            <Storyboard>
                                <BooleanAnimationUsingKeyFrames   Storyboard.TargetProperty="IsDropDownOpen">
                                    <DiscreteBooleanKeyFrame Value="True" KeyTime="0:0:0" />
                                </BooleanAnimationUsingKeyFrames>
                            </Storyboard>
                        </BeginStoryboard>
                    </EventTrigger>
                </ComboBox.Triggers>
            </ComboBox>
        </DataTemplate>
    </Setter.Value>
</Setter>

Answer 1

You can set the Source of each binding like you are currently doing for the ItemsSource property:

ItemsSource="{Binding Path=FilteredSource, Source={StaticResource ItemsVM}}"

If you don't do this, the framework will look for the FilteredSource property in the current DataContext of the ComboBox .

By the way, the DisplayMemberPath property should be set to a string that specifies the name of a property of an item in the ItemsSource :

DisplayMemberPath="Name"

You should not bind to this property.

It also makes no sense to set the UpdateSourceTrigger property for an ItemsSource binding to PropertyChanged , or set the Mode to TwoWay , since the control won't set the source property.