AutoCompleteBox with items enabled or disabled.

[Cyril]

Hi !

We try to make an autocompletebox where some of the items could be disabled individually.

We first try to make a BoxesItemTemplate but the item’s “little cross” which delete the selected items from the list where not in there.

So we decided to make a Style/template for the complete “autocompletebox”.
In this style we define the item container style in order not to have the "little cross":

<telerik1:AutoCompleteBoxesItemsControl.ItemContainerStyle>
  <Style TargetType="{x:Type telerik1:RadAutoCompleteBoxItem}">
     <Setter Property="Template">
         <Setter.Value>
            <ControlTemplate TargetType="{x:Type telerik1:RadAutoCompleteBoxItem}">
                <Border CornerRadius="1" x:Name="Bd" SnapsToDevicePixels="true" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding                         BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}">
                   <StackPanel Orientation="Horizontal">
                     <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding                       VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>

                    </StackPanel>
                </Border>
           </ControlTemplate>
        </Setter.Value>
    </Setter>
  </Style>
</telerik1:AutoCompleteBoxesItemsControl.ItemContainerStyle>

And we did a BoxesItemTemplate in which we put a button for the "little cross" that should delete the item when pressed. But then we were enabled to bind to the delete command (the command that delete the item).
On our button we try some things like :

Command="telerik:RadAutoCompleteBoxCommands.RemoveItem"

But it does not work. I suppose we do not give the write arguments (perhaps the "item" as parametter)

Do you have any solution?

FOR INFORMATION:
The AutoCompleteBox object:

<telerik1:RadAutoCompleteBox Grid.Row="0"
                                    x:Name="RadAutoCompleteBox" Height="30" Margin="5"
                                    TextSearchPath="SearchString"
                                    TextSearchMode="Contains"
                                    AutoCompleteMode="Suggest"
                                    DropDownItemTemplate="{StaticResource CustomDropDownItemTemplate}"
                                    SearchTextChanged="RadAutoCompleteBox_OnSearchTextChanged" Style="{DynamicResource RadAutoCompleteBoxGinkgoStyle}"
                                    >

            <telerik1:RadAutoCompleteBox.BoxesItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding DisplayString}"/>
                        <Button Width="10" Height="10" Margin="3,0,0,0" Click="Button_Click"  Cursor="Arrow">
                            <Button.Template>
                                <ControlTemplate>
                                    <Grid>
                                        <Rectangle Stroke="Black"  />
                                        <Path Data="M0,0 L100,100" Margin="2,2,2,2" Stretch="Fill" Stroke="Black"/>
                                        <Path Data="M100,0 L0,100" Margin="2,2,2,2" Stretch="Fill" Stroke="Black" />
                                    </Grid>
                                </ControlTemplate>
                            </Button.Template>
                        </Button>
                    </StackPanel>
                </DataTemplate>
           </telerik1:RadAutoCompleteBox.BoxesItemTemplate>
       </telerik1:RadAutoCompleteBox>

The complete style/template:

<Style x:Key="RadAutoCompleteBoxGinkgoStyle" TargetType="{x:Type telerik1:RadAutoCompleteBox}">
           <Setter Property="IsTabStop" Value="False"/>
           <Setter Property="TextBoxStyle">
               <Setter.Value>
                   <Style TargetType="{x:Type telerik1:RadWatermarkTextBox}">
                       <Setter Property="BorderThickness" Value="0"/>
                       <Setter Property="Margin" Value="3,3,0,0"/>
                       <Setter Property="Padding" Value="0"/>
                       <Setter Property="BorderBrush" Value="Transparent"/>
                       <Setter Property="Background" Value="Transparent"/>
                       <Setter Property="Template">
                           <Setter.Value>
                               <ControlTemplate TargetType="{x:Type telerik1:RadWatermarkTextBox}">
                                   <Grid x:Name="RootElement" Cursor="IBeam">
                                       <VisualStateManager.VisualStateGroups>
                                           <VisualStateGroup x:Name="CommonStates">
                                               <VisualState x:Name="Normal">
                                                   <Storyboard>
                                                       <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="Opacity" Storyboard.TargetName="MouseOverVisual">
                                                           <LinearDoubleKeyFrame KeyTime="0:0:0.15" Value="0"/>
                                                       </DoubleAnimationUsingKeyFrames>
                                                       <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="MouseOverVisual">
                                                           <DiscreteObjectKeyFrame KeyTime="0:0:0.15">
                                                               <DiscreteObjectKeyFrame.Value>
                                                                   <Visibility>Collapsed</Visibility>
                                                               </DiscreteObjectKeyFrame.Value>
                                                           </DiscreteObjectKeyFrame>
                                                       </ObjectAnimationUsingKeyFrames>
                                                   </Storyboard>
                                               </VisualState>
                                               <VisualState x:Name="MouseOver">
                                                   <Storyboard>
                                                       <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="Opacity" Storyboard.TargetName="MouseOverVisual">
                                                           <LinearDoubleKeyFrame KeyTime="0:0:0.115" Value="1"/>
                                                       </DoubleAnimationUsingKeyFrames>
                                                       <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="MouseOverVisual">
                                                           <DiscreteObjectKeyFrame KeyTime="0">
                                                               <DiscreteObjectKeyFrame.Value>
                                                                   <Visibility>Visible</Visibility>
                                                               </DiscreteObjectKeyFrame.Value>
                                                           </DiscreteObjectKeyFrame>
                                                       </ObjectAnimationUsingKeyFrames>
                                                   </Storyboard>
                                               </VisualState>
                                               <VisualState x:Name="Disabled">
                                                   <Storyboard>
                                                       <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="DisabledVisualElement"/>
                                                       <DoubleAnimation Duration="0" To="0.6" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="PART_ContentHost"/>
                                                   </Storyboard>
                                               </VisualState>
                                           </VisualStateGroup>
                                           <VisualStateGroup x:Name="WatermarkStates">
                                               <VisualState x:Name="WatermarkHidden">
                                                   <Storyboard>
                                                       <DoubleAnimation Duration="0" To="0" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="WatermarkVisualElement"/>
                                                   </Storyboard>
                                               </VisualState>
                                               <VisualState x:Name="WatermarkVisible"/>
                                           </VisualStateGroup>
                                       </VisualStateManager.VisualStateGroups>
                                       <Border x:Name="Border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Opacity="1"/>
                                       <Border x:Name="MouseOverVisual" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="2" Visibility="Collapsed"/>
                                       <Border x:Name="DisabledVisualElement" BorderBrush="#FF989898" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" IsHitTestVisible="False" Opacity="0"/>
                                       <ScrollViewer x:Name="PART_ContentHost" BorderThickness="0" IsTabStop="False" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                                           <telerik1:StyleManager.Theme>
                                               <telerik1:Office_BlackTheme/>
                                           </telerik1:StyleManager.Theme>
                                       </ScrollViewer>
                                       <Border x:Name="FocusVisual" BorderBrush="#FFFFC92B" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" CornerRadius="1" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="2">
                                           <Border BorderBrush="Transparent" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="0"/>
                                       </Border>
                                       <ContentControl x:Name="WatermarkVisualElement" BorderThickness="{TemplateBinding BorderThickness}" ContentTemplate="{TemplateBinding WatermarkTemplate}" Content="{TemplateBinding WatermarkContent}" FontStyle="Italic" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="False" IsTabStop="False" Margin="{TemplateBinding Padding}" Opacity="0.5" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                                   </Grid>
                               </ControlTemplate>
                           </Setter.Value>
                       </Setter>
                       <Style.BasedOn>
                           <Style TargetType="{x:Type telerik1:RadWatermarkTextBox}">
                               <Setter Property="Foreground" Value="Black"/>
                               <Setter Property="Padding" Value="5,3"/>
                               <Setter Property="VerticalContentAlignment" Value="Center"/>
                               <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                               <Setter Property="AllowDrop" Value="True"/>
                               <Setter Property="IsTabStop" Value="True"/>
                               <Setter Property="BorderBrush" Value="#FF848484"/>
                               <Setter Property="Background" Value="White"/>
                               <Setter Property="BorderThickness" Value="1"/>
                               <Setter Property="KeyboardNavigation.TabNavigation" Value="Once"/>
                               <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
                               <Setter Property="SnapsToDevicePixels" Value="True"/>
                               <Setter Property="Template">
                                   <Setter.Value>
                                       <ControlTemplate TargetType="{x:Type telerik1:RadWatermarkTextBox}">
                                           <Grid x:Name="RootElement" Cursor="IBeam">
                                               <VisualStateManager.VisualStateGroups>
                                                   <VisualStateGroup x:Name="CommonStates">
                                                       <VisualState x:Name="Normal">
                                                           <Storyboard>
                                                               <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="Opacity" Storyboard.TargetName="MouseOverVisual">
                                                                   <LinearDoubleKeyFrame KeyTime="0:0:0.15" Value="0"/>
                                                               </DoubleAnimationUsingKeyFrames>
                                                               <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="MouseOverVisual">
                                                                   <DiscreteObjectKeyFrame KeyTime="0:0:0.15">
                                                                       <DiscreteObjectKeyFrame.Value>
                                                                           <Visibility>Collapsed</Visibility>
                                                                       </DiscreteObjectKeyFrame.Value>
                                                                   </DiscreteObjectKeyFrame>
                                                               </ObjectAnimationUsingKeyFrames>
                                                           </Storyboard>
                                                       </VisualState>
                                                       <VisualState x:Name="MouseOver">
                                                           <Storyboard>
                                                               <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="Opacity" Storyboard.TargetName="MouseOverVisual">
                                                                   <LinearDoubleKeyFrame KeyTime="0:0:0.115" Value="1"/>
                                                               </DoubleAnimationUsingKeyFrames>
                                                               <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="MouseOverVisual">
                                                                   <DiscreteObjectKeyFrame KeyTime="0">
                                                                       <DiscreteObjectKeyFrame.Value>
                                                                           <Visibility>Visible</Visibility>
                                                                       </DiscreteObjectKeyFrame.Value>
                                                                   </DiscreteObjectKeyFrame>
                                                               </ObjectAnimationUsingKeyFrames>
                                                           </Storyboard>
                                                       </VisualState>
                                                       <VisualState x:Name="Disabled">
                                                           <Storyboard>
                                                               <DoubleAnimation Duration="0" To="0.6" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="DisabledVisualElement"/>
                                                               <DoubleAnimation Duration="0" To="0.6" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="PART_ContentHost"/>
                                                           </Storyboard>
                                                       </VisualState>
                                                       <VisualState x:Name="ReadOnly">
                                                           <Storyboard>
                                                               <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="ReadOnlyVisualElement"/>
                                                           </Storyboard>
                                                       </VisualState>
                                                   </VisualStateGroup>
                                                   <VisualStateGroup x:Name="FocusStates">
                                                       <VisualState x:Name="Focused">
                                                           <Storyboard>
                                                               <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisual"/>
                                                           </Storyboard>
                                                       </VisualState>
                                                       <VisualState x:Name="Unfocused"/>
                                                   </VisualStateGroup>
                                                   <VisualStateGroup x:Name="WatermarkStates">
                                                       <VisualState x:Name="WatermarkHidden">
                                                           <Storyboard>
                                                               <DoubleAnimation Duration="0" To="0" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="WatermarkVisualElement"/>
                                                           </Storyboard>
                                                       </VisualState>
                                                       <VisualState x:Name="WatermarkVisible"/>
                                                   </VisualStateGroup>
                                               </VisualStateManager.VisualStateGroups>
                                               <Border x:Name="Border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="1" Opacity="1"/>
                                               <Border x:Name="ReadOnlyVisualElement" Background="#5EC9C9C9" CornerRadius="1" Opacity="0"/>
                                               <Border x:Name="MouseOverVisual" BorderBrush="#FFFFC92B" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" CornerRadius="1" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="2" Visibility="Collapsed"/>
                                               <Border x:Name="DisabledVisualElement" BorderBrush="#FF989898" BorderThickness="{TemplateBinding BorderThickness}" Background="#FFE0E0E0" CornerRadius="1" IsHitTestVisible="False" Opacity="0"/>
                                               <ScrollViewer x:Name="PART_ContentHost" BorderThickness="0" Cursor="Arrow" IsTabStop="False" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                                                   <telerik1:StyleManager.Theme>
                                                       <telerik1:Office_BlackTheme/>
                                                   </telerik1:StyleManager.Theme>
                                               </ScrollViewer>
                                               <Border x:Name="FocusVisual" BorderBrush="#FFFFC92B" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" CornerRadius="1" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="2">
                                                   <Border BorderBrush="Transparent" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="0"/>
                                               </Border>
                                               <ContentControl x:Name="WatermarkVisualElement" BorderThickness="{TemplateBinding BorderThickness}" ContentTemplate="{TemplateBinding WatermarkTemplate}" Content="{TemplateBinding WatermarkContent}" Foreground="{TemplateBinding Foreground}" FontStyle="Italic" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="False" IsTabStop="False" Margin="2,0,0,0" Opacity="0.5" Padding="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                                                   <ContentControl.Template>
                                                       <ControlTemplate TargetType="{x:Type ContentControl}">
                                                           <Border BorderThickness="{TemplateBinding BorderThickness}">
                                                               <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}" Margin="{TemplateBinding Padding}"/>
                                                           </Border>
                                                       </ControlTemplate>
                                                   </ContentControl.Template>
                                               </ContentControl>
                                           </Grid>
                                       </ControlTemplate>
                                   </Setter.Value>
                               </Setter>
                           </Style>
                       </Style.BasedOn>
                   </Style>
               </Setter.Value>
           </Setter>
           <Setter Property="Template">
               <Setter.Value>
                   <ControlTemplate TargetType="{x:Type telerik1:RadAutoCompleteBox}">
                       <Grid>
                           <VisualStateManager.VisualStateGroups>
                               <VisualStateGroup x:Name="CommonStates">
                                   <VisualState x:Name="Normal"/>
                                   <VisualState x:Name="MouseOver">
                                       <Storyboard>
                                           <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="MouseOverVisual"/>
                                       </Storyboard>
                                   </VisualState>
                                   <VisualState x:Name="Disabled">
                                       <Storyboard>
                                           <DoubleAnimation Duration="0" To="0.6" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="DisabledVisualElement"/>
                                       </Storyboard>
                                   </VisualState>
                               </VisualStateGroup>
                               <VisualStateGroup x:Name="FocusStates">
                                   <VisualState x:Name="Unfocused"/>
                                   <VisualState x:Name="Focused">
                                       <Storyboard>
                                           <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisual"/>
                                       </Storyboard>
                                   </VisualState>
                               </VisualStateGroup>
                           </VisualStateManager.VisualStateGroups>
                           <Border x:Name="Border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="1"/>
                           <Border x:Name="MouseOverVisual" BorderBrush="#FFFFC92B" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="1" Opacity="0"/>
                           <Border x:Name="FocusVisual" BorderBrush="#FFFFC92B" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="1" IsHitTestVisible="False" Opacity="0">
                               <Border BorderBrush="Transparent" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="0"/>
                           </Border>
                           <Border x:Name="DisabledVisualElement" BorderBrush="#FF989898" BorderThickness="{TemplateBinding BorderThickness}" Background="#FFE0E0E0" CornerRadius="1" IsHitTestVisible="False" Opacity="0"/>
                           <ScrollViewer x:Name="PART_ScrollViewer" BorderThickness="0" Background="Transparent" Height="{TemplateBinding Height}" HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}" IsTabStop="False" Margin="{TemplateBinding BorderThickness}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                               <telerik1:StyleManager.Theme>
                                   <telerik1:Office_BlackTheme/>
                               </telerik1:StyleManager.Theme>
                               <telerik1:AutoCompleteBoxesItemsControl x:Name="PART_Boxes"
                                                                      BoxesItemTemplate="{TemplateBinding BoxesItemTemplate}"
                                                                      DisplayMemberPath="{TemplateBinding DisplayMemberPath}"
                                                                      Foreground="{TemplateBinding Foreground}"
                                                                      Height="{TemplateBinding Height}"
                                                                      ScrollViewer.HorizontalScrollBarVisibility="Disabled"
                                                                      IsTabStop="False"
                                                                      Margin="{TemplateBinding Padding}"
                                                                      ScrollViewer.VerticalScrollBarVisibility="Disabled" >
                                   <telerik1:AutoCompleteBoxesItemsControl.ItemsPanel>
                                       <ItemsPanelTemplate>
                                           <telerik1:AutoCompleteBoxesWrapPanel IsItemsHost="True" Width="{Binding ActualWidth, ElementName=WatermarkTextBox}"/>
                                       </ItemsPanelTemplate>
                                  </telerik1:AutoCompleteBoxesItemsControl.ItemsPanel>

                                   <telerik1:AutoCompleteBoxesItemsControl.ItemContainerStyle>
                                       <Style TargetType="{x:Type telerik1:RadAutoCompleteBoxItem}">
                                           <Setter Property="Template">
                                               <Setter.Value>
                                                   <ControlTemplate TargetType="{x:Type telerik1:RadAutoCompleteBoxItem}">
                                                       <Border CornerRadius="1" x:Name="Bd" SnapsToDevicePixels="true" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}">
                                                           <StackPanel Orientation="Horizontal">
                                                               <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>

                                                           </StackPanel>

                                                       </Border>
                                                   </ControlTemplate>
                                               </Setter.Value>
                                           </Setter>
                                       </Style>
                                  </telerik1:AutoCompleteBoxesItemsControl.ItemContainerStyle>

                              </telerik1:AutoCompleteBoxesItemsControl>
                           </ScrollViewer>
                           <Popup x:Name="PART_Popup">
                               <Grid x:Name="PopupRoot">
                                   <telerik1:RadListBox x:Name="PART_ListBox"
                                                        CanKeyboardNavigationSelectItems="{x:Null}"
                                                        IsTabStop="False"
                                                        ItemTemplate="{TemplateBinding DropDownItemTemplate}"
                                                        IsTextSearchEnabled="True"
                                                        MaxHeight="{TemplateBinding MaxDropDownHeight}"
                                                        MinWidth="{TemplateBinding MinDropDownWidth}"
                                                        SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
                                                        SelectedValueBinding="{x:Null}"
                                                        TextBinding="{x:Null}"
                                                        ItemsSource="{TemplateBinding FilteredItems}">

                                       <telerik1:StyleManager.Theme>
                                           <telerik1:Office_BlackTheme/>
                                       </telerik1:StyleManager.Theme>
                                   </telerik1:RadListBox>
                               </Grid>
                           </Popup>
                       </Grid>
                   </ControlTemplate>
               </Setter.Value>
           </Setter>
           <Setter Property="BorderBrush" Value="#FF848484"/>
           <Setter Property="BorderThickness" Value="1"/>
           <Setter Property="Background" Value="White"/>
           <Setter Property="Padding" Value="0,0,3,3"/>
           <Setter Property="Cursor" Value="IBeam"/>
           <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Disabled"/>
           <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled"/>
           <Setter Property="SnapsToDevicePixels" Value="True"/>
       </Style>

[Vladi]

Hi,

All you need to do to customize the remove button in the BoxItems is customize the
RadAutoCompleteBoxItemStyle's Template:

• First you should create a boolean property in the objects that are bound to the ItemsSource collection of the AutoCompleteBox control that will be bound to the IsEnabled property of the remove button.
• Customize the RadAutoCompleteBoxItemStyle's Template and add a binding to the IsEnabled of the RadButton with x:Name="RemoveItemButton".

I created and attached a sample project for you with the previously described approach, hope this is helpful. The example project uses Implicit Styles in order to customize the RadAutoCompleteBoxItemStyle.

Regards,
Vladi
Telerik