Class ComboBoxItemDisplayBehavior

Provides different ItemTemplates and/or an additional empty item for a System.Windows.Controls.ComboBox.

Inheritance

System.Object

System.Windows.Threading.DispatcherObject

System.Windows.DependencyObject

System.Windows.Freezable

System.Windows.Media.Animation.Animatable

Microsoft.Xaml.Behaviors.Behavior

Microsoft.Xaml.Behaviors.Behavior<System.Windows.Controls.ComboBox>

ComboBoxItemDisplayBehavior

Implements

System.Windows.Media.Animation.IAnimatable

Microsoft.Xaml.Behaviors.IAttachedObject

Inherited Members

Microsoft.Xaml.Behaviors.Behavior<System.Windows.Controls.ComboBox>.AssociatedObject

Microsoft.Xaml.Behaviors.Behavior.CreateInstanceCore()

Microsoft.Xaml.Behaviors.Behavior.Attach(System.Windows.DependencyObject)

Microsoft.Xaml.Behaviors.Behavior.Detach()

Microsoft.Xaml.Behaviors.Behavior.AssociatedType

Microsoft.Xaml.Behaviors.Behavior.Microsoft.Xaml.Behaviors.IAttachedObject.AssociatedObject

System.Windows.Media.Animation.Animatable.ApplyAnimationClock(System.Windows.DependencyProperty, System.Windows.Media.Animation.AnimationClock)

System.Windows.Media.Animation.Animatable.ApplyAnimationClock(System.Windows.DependencyProperty, System.Windows.Media.Animation.AnimationClock, System.Windows.Media.Animation.HandoffBehavior)

System.Windows.Media.Animation.Animatable.BeginAnimation(System.Windows.DependencyProperty, System.Windows.Media.Animation.AnimationTimeline)

System.Windows.Media.Animation.Animatable.BeginAnimation(System.Windows.DependencyProperty, System.Windows.Media.Animation.AnimationTimeline, System.Windows.Media.Animation.HandoffBehavior)

System.Windows.Media.Animation.Animatable.Clone()

System.Windows.Media.Animation.Animatable.FreezeCore(System.Boolean)

System.Windows.Media.Animation.Animatable.GetAnimationBaseValue(System.Windows.DependencyProperty)

System.Windows.Media.Animation.Animatable.HasAnimatedProperties

System.Windows.Freezable.CloneCore(System.Windows.Freezable)

System.Windows.Freezable.CloneCurrentValue()

System.Windows.Freezable.CloneCurrentValueCore(System.Windows.Freezable)

System.Windows.Freezable.CreateInstance()

System.Windows.Freezable.Freeze()

System.Windows.Freezable.Freeze(System.Windows.Freezable, System.Boolean)

System.Windows.Freezable.GetAsFrozen()

System.Windows.Freezable.GetAsFrozenCore(System.Windows.Freezable)

System.Windows.Freezable.GetCurrentValueAsFrozen()

System.Windows.Freezable.GetCurrentValueAsFrozenCore(System.Windows.Freezable)

System.Windows.Freezable.OnChanged()

System.Windows.Freezable.OnFreezablePropertyChanged(System.Windows.DependencyObject, System.Windows.DependencyObject)

System.Windows.Freezable.OnFreezablePropertyChanged(System.Windows.DependencyObject, System.Windows.DependencyObject, System.Windows.DependencyProperty)

System.Windows.Freezable.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)

System.Windows.Freezable.ReadPreamble()

System.Windows.Freezable.WritePostscript()

System.Windows.Freezable.WritePreamble()

System.Windows.Freezable.CanFreeze

System.Windows.Freezable.IsFrozen

System.Windows.Freezable.Changed

System.Windows.DependencyObject.ClearValue(System.Windows.DependencyProperty)

System.Windows.DependencyObject.ClearValue(System.Windows.DependencyPropertyKey)

System.Windows.DependencyObject.CoerceValue(System.Windows.DependencyProperty)

System.Windows.DependencyObject.Equals(System.Object)

System.Windows.DependencyObject.GetHashCode()

System.Windows.DependencyObject.GetLocalValueEnumerator()

System.Windows.DependencyObject.GetValue(System.Windows.DependencyProperty)

System.Windows.DependencyObject.InvalidateProperty(System.Windows.DependencyProperty)

System.Windows.DependencyObject.ReadLocalValue(System.Windows.DependencyProperty)

System.Windows.DependencyObject.SetCurrentValue(System.Windows.DependencyProperty, System.Object)

System.Windows.DependencyObject.SetValue(System.Windows.DependencyProperty, System.Object)

System.Windows.DependencyObject.SetValue(System.Windows.DependencyPropertyKey, System.Object)

System.Windows.DependencyObject.ShouldSerializeProperty(System.Windows.DependencyProperty)

System.Windows.DependencyObject.DependencyObjectType

System.Windows.DependencyObject.IsSealed

System.Windows.Threading.DispatcherObject.Dispatcher

System.Object.Equals(System.Object, System.Object)

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: Sartorius.SAF.Presentation.Behaviors

Assembly: Sartorius.SAF.Presentation.dll

Syntax

public class ComboBoxItemDisplayBehavior : Behavior<ComboBox>, IAnimatable, IAttachedObject

Remarks

This behavior provides three additional templates for items in a System.Windows.Controls.ComboBox.

The SelectionBoxItemTemplate is used for items inside the SelectionBox of the System.Windows.Controls.ComboBox. This is the template for the currently selected item. If this is null the default System.Windows.Controls.ItemsControl.ItemTemplate is used.

The EmptyItemTemplate is used for the empty item defined by EmptyItemObject inside the dropdown. If this is null the default System.Windows.Controls.ItemsControl.ItemTemplate is used.

The SelectionBoxEmptyItemTemplate is used for the empty item defined by EmptyItemObject in the SelectionBox. Use this template for 'Please Select' messages. If this is null the SelectionBoxItemTemplate is used.

The behavior will respect an existing System.Windows.Controls.ItemsControl.ItemTemplateSelector for items in the dropdown. This existing ItemTemplateSelector will only be used for the System.Windows.Controls.ItemsControl.ItemTemplate or when other templates are not available.

If EmptyItemObject is set an additional entry that acts as null-selection is shown. This will be displayed according to the current data templates. When this additional entry is selected in the drop down it will unselect the current selection. If you set either SelectionBoxEmptyItemTemplate or SelectionBoxEmptyItemText but EmptyItemObject is null the template or the text will be displayed when currently no item is selected. If EmptyItemTemplate or EmptyItemText are set an entry that unselects the current value will be shown.

Do not use this behavior on a dropdown showing value types. The empty selection is converted to null. Your databinding will break and create undesired results.

Examples

The following example code shows a System.Windows.Controls.ComboBox with a 'Please Select message' when nothing is selected and a 'Clear Selection'-Entry in the DropDown. Items can be multiline in the dropdown and are trimmed in the SelectionBox.

 <UserControl.Resources>
   <ResourceDictionary>
<!-- This must be an object with accessible Property named 'Name' and an parameterless constructor -->
       <data:DropDownItem x:Key="EmptyItemObject">
           <data:DropDownItem.Name>Clear Selection</data:DropDownItem.Name>
       </data:DropDownItem>
   </ResourceDictionary>
</UserControl.Resources>
...

<ComboBox
    x:Name="comboBox"
    ItemsSource="{Binding Items}"
    SelectedValuePath="Value"
    SelectedValue="{Binding SelectedValue}"
    SelectedItem="{Binding SelectedItem}"
    ItemContainerStyle="{DynamicResource SAF_ComboBox_ComboBoxItem}" Style="{DynamicResource SAF_ComboBox}">
    <i:Interaction.Behaviors>
        <SAF:ComboBoxItemDisplayBehavior EmptyItemObject='{StaticResource EmptyItemObject}'>
            <SAF:ComboBoxItemDisplayBehavior.SelectionBoxItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding Name}"
                               Style="{DynamicResource SAF_TextBlock}"
                               TextWrapping="NoWrap"
                               TextTrimming="CharacterEllipsis" />
                </DataTemplate>
            </SAF:ComboBoxItemDisplayBehavior.SelectionBoxItemTemplate>
            <SAF:ComboBoxItemDisplayBehavior.SelectionBoxEmptyItemTemplate>
                <DataTemplate>
                    <TextBlock Text="Please Select"
                               Style="{DynamicResource SAF_TextBlock}"
                               Opacity="0.5"
                               TextWrapping="NoWrap"
                               TextTrimming="CharacterEllipsis" />
                </DataTemplate>
            </SAF:ComboBoxItemDisplayBehavior.SelectionBoxEmptyItemTemplate>
        </SAF:ComboBoxItemDisplayBehavior>
    </i:Interaction.Behaviors>
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Name}"
		Style="{DynamicResource SAF_TextBlock}"
		TextWrapping="Wrap" />
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

The following example shows how to add an empty item with default templates

<ComboBox ItemsSource="{Binding Customers}"
          SelectedItem="{Binding SelectedItem}"
          DisplayMemberPath="FirstName"
          MaxWidth="200"
          ScrollViewer.HorizontalScrollBarVisibility="Disabled"
          Width="200">
    <i:Interaction.Behaviors>
        <SAF:ComboBoxItemDisplayBehavior EmptyItemText="[Unselect]"
                                          SelectionBoxEmptyItemText="Please select an item"
                                          SelectionBoxEmptyItemForeground="#DADADA" />
    </i:Interaction.Behaviors>
</ComboBox>

Fields

DisplayMemberPathProperty

Identifies the dependency property for DisplayMemberPath.

Declaration

public static readonly DependencyProperty DisplayMemberPathProperty

Field Value

Type	Description
System.Windows.DependencyProperty

EmptyItemObjectProperty

Declaration

public static readonly DependencyProperty EmptyItemObjectProperty

Field Value

Type	Description
System.Windows.DependencyProperty

EmptyItemTemplateProperty

Identifies the dependency property for EmptyItemTemplateProperty.

Declaration

public static readonly DependencyProperty EmptyItemTemplateProperty

Field Value

Type	Description
System.Windows.DependencyProperty

EmptyItemTextProperty

Identifies the depnedency property for EmptyItemText.

Declaration

public static readonly DependencyProperty EmptyItemTextProperty

Field Value

Type	Description
System.Windows.DependencyProperty

SelectionBoxEmptyItemForegroundProperty

Identifies the dependency property for SelectionBoxEmptyItemForeground.

Declaration

public static readonly DependencyProperty SelectionBoxEmptyItemForegroundProperty

Field Value

Type	Description
System.Windows.DependencyProperty

SelectionBoxEmptyItemTemplateProperty

Declaration

public static readonly DependencyProperty SelectionBoxEmptyItemTemplateProperty

Field Value

Type	Description
System.Windows.DependencyProperty

SelectionBoxEmptyItemTextProperty

Identifies the dependency property for SelectionBoxEmptyItemText.

Declaration

public static readonly DependencyProperty SelectionBoxEmptyItemTextProperty

Field Value

Type	Description
System.Windows.DependencyProperty

SelectionBoxItemTemplateProperty

The dependency property for SelectionBoxItemTemplate.

Declaration

public static readonly DependencyProperty SelectionBoxItemTemplateProperty

Field Value

Type	Description
System.Windows.DependencyProperty

SelectionBoxItemTemplateSelectorProperty

Identifies the dependency property for SelectionBoxItemTemplateSelector.

Declaration

public static readonly DependencyProperty SelectionBoxItemTemplateSelectorProperty

Field Value

Type	Description
System.Windows.DependencyProperty

Properties

DisplayMemberPath

Gets or sets the member path to the text that should be displayed. You do not need to set this if System.Windows.Controls.ItemsControl.DisplayMemberPath is set on the associated combobox or if you set EmptyItemObject.

Declaration

public string DisplayMemberPath { get; set; }

Property Value

Type	Description
System.String

Examples

<ComboBox x:Name="comboBox" ItemsSource="{Binding Customers}" ScrollViewer.HorizontalScrollBarVisibility="Disabled" SelectedValuePath="Id" SelectedValue="{Binding SelectedId}" SelectedItem="{Binding SelectedItem}" ItemContainerStyle="{DynamicResource SAF_ComboBox_ComboBoxItem}" Style="{DynamicResource SAF_ComboBox}"> <i:Interaction.Behaviors> <SAF:ComboBoxItemDisplayBehavior EmptyItemText="[Unselect]" DisplayMemberPath="FirstName"> <SAF:ComboBoxItemDisplayBehavior.SelectionBoxItemTemplate> <DataTemplate> <TextBlock Text="{Binding FirstName}" Style="{DynamicResource SAF_TextBlock}" TextWrapping="NoWrap" TextTrimming="CharacterEllipsis" /> </DataTemplate> </SAF:ComboBoxItemDisplayBehavior.SelectionBoxItemTemplate> <SAF:ComboBoxItemDisplayBehavior.SelectionBoxEmptyItemTemplate> <DataTemplate> <TextBlock Text="Please Select" Style="{DynamicResource SAF_TextBlock}" Opacity="0.5" TextWrapping="NoWrap" TextTrimming="CharacterEllipsis" /> </DataTemplate> </SAF:ComboBoxItemDisplayBehavior.SelectionBoxEmptyItemTemplate> </SAF:ComboBoxItemDisplayBehavior> </i:Interaction.Behaviors> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding FirstName}" Style="{DynamicResource SAF_TextBlock}" TextWrapping="Wrap" /> </DataTemplate> </ComboBox.ItemTemplate> </ComboBox>

EmptyItemObject

Gets or sets the object which defines the empty item. Use this if you have to use some data-binding in templates for the empty item.

Declaration

public object EmptyItemObject { get; set; }

Property Value

Type	Description
System.Object

Remarks

If you do not need advanced data-binding in templates use DisplayMemberPath, SelectionBoxEmptyItemText and EmptyItemText or use EmptyItemTemplate and SelectionBoxEmptyItemTemplate without advanced bindings.

EmptyItemTemplate

Gets or sets the System.Windows.DataTemplate that should be used for an empty item.

Declaration

public DataTemplate EmptyItemTemplate { get; set; }

Property Value

Type	Description
System.Windows.DataTemplate

Remarks

When this is null the default System.Windows.Controls.ItemsControl.ItemTemplate of the associated System.Windows.Controls.ComboBox is used.

EmptyItemText

Gets or sets the text that is displayed for the EmptyItemObject in the dropdown popup.

Declaration

public string EmptyItemText { get; set; }

Property Value

Type	Description
System.String

SelectionBoxEmptyItemForeground

Gets or sets the foreground color for the EmptyItemObject in the SelectionBox. This is not used when SelectionBoxEmptyItemTemplate exists and System.Windows.Controls.ItemsControl.DisplayMemberPath on the associated combobox or DisplayMemberPath are set.

Declaration

public Brush SelectionBoxEmptyItemForeground { get; set; }

Property Value

Type	Description
System.Windows.Media.Brush

SelectionBoxEmptyItemTemplate

Gets or sets the System.Windows.DataTemplate that should be used for an empty item in the SelectionBox.

Declaration

public DataTemplate SelectionBoxEmptyItemTemplate { get; set; }

Property Value

Type	Description
System.Windows.DataTemplate

Remarks

When this is null the SelectionBoxItemTemplate is used.

SelectionBoxEmptyItemText

Gets or sets the text that is displayed for the EmptyItemObject in the SelectionBox. This is not used when SelectionBoxEmptyItemTemplate exists and System.Windows.Controls.ItemsControl.DisplayMemberPath on the associated combobox or DisplayMemberPath are set.

Declaration

public string SelectionBoxEmptyItemText { get; set; }

Property Value

Type	Description
System.String

SelectionBoxItemTemplate

Gets or sets the System.Windows.DataTemplate that should be used for the SelectionBox of the System.Windows.Controls.ComboBox

Declaration

public DataTemplate SelectionBoxItemTemplate { get; set; }

Property Value

Type	Description
System.Windows.DataTemplate

Remarks

When this is null the default System.Windows.Controls.ItemsControl.ItemTemplate of the associated System.Windows.Controls.ComboBox is used.

SelectionBoxItemTemplateSelector

Gets or sets the custom logic for choosing a template used to display each item in the selection box.

Declaration

public DataTemplateSelector SelectionBoxItemTemplateSelector { get; set; }

Property Value

Type	Description
System.Windows.Controls.DataTemplateSelector

Remarks

This property is ignored if SelectionBoxItemTemplate is set.

Methods

OnAttached()

Called after the behavior is attached to an AssociatedObject.

Declaration

protected override void OnAttached()

Overrides

Microsoft.Xaml.Behaviors.Behavior.OnAttached()

Remarks

Override this to hook up functionality to the AssociatedObject.

OnDetaching()

Called when the behavior is being detached from its AssociatedObject, but before it has actually occurred.

Declaration

protected override void OnDetaching()

Overrides

Microsoft.Xaml.Behaviors.Behavior.OnDetaching()

Remarks

Override this to unhook functionality from the AssociatedObject.

Implements

System.Windows.Media.Animation.IAnimatable

Microsoft.Xaml.Behaviors.IAttachedObject

Extension Methods

CollectionExtensions.AddRange<T, TCollection>(TCollection, IEnumerable<T>)

SerializableObjectCloneExtension.Clone<T>(T)

DependencyObjectExtensions.GetContainer(DependencyObject)

DependencyObjectExtensions.SetContainer(DependencyObject, CompositionContainer)

DependencyObjectExtensions.FindAncestor<T>(DependencyObject)

DependencyObjectExtensions.FindFirstChildByType<T>(DependencyObject)

DependencyObjectExtensions.FindLogicalAncestor<T>(DependencyObject)

DependencyObjectExtensions.GetChildsByType<T>(DependencyObject, List<T>)

DependencyObjectExtensions.GetChildrenByType<T>(DependencyObject)

DependencyObjectExtensions.XamlClone<T>(T)