在WPF中自定义ScrollViewer

Question

我正在开发一个具有自定义ComboBox的应用程序。

ComboBox的外观应该是这样的。

我已将ComboBox的ControlTemplate修改为如上所示。

问题是： 当我继续按下禁用的重复按钮时，也禁用了Up RepeatButton（以编程方式禁用）项目被选中。

我使用的控件模板是：  

            <Setter
                Property    ="SnapsToDevicePixels"
                Value       ="True"
                />

            <Setter
                Property    ="FocusVisualStyle"
                Value       ="{DynamicResource ComboFocusVisualStyle}"
                />

            <Setter
                Property    ="Foreground"
                Value       ="Black"
                />

            <Setter
                Property    ="Template"
                >

                <Setter.Value>

                    <ControlTemplate
                        TargetType  ="{x:Type ComboBox}"
                        >

                        <Grid>

                            <Border 
                                CornerRadius    ="3"
                                BorderThickness ="0,0,0,.7" 
                                BorderBrush     ="WhiteSmoke"
                                >

                                <Border 
                                    Name                ="brd1"
                                    CornerRadius        ="3"                                          
                                    BorderBrush         ="{StaticResource ComboBorderBrush}" 
                                    BorderThickness     ="1,1,1,1"
                                    Background          ="{TemplateBinding Background}"                                       
                                    ToolTip             ="{TemplateBinding SelectionBoxItem, Converter={StaticResource ToolTipConverter}, ConverterParameter=PrinterInfoCol}"
                                    >

                                    <Grid>

                                        <ContentPresenter
                                            x:Name              ="ContentSite"
                                            HorizontalAlignment ="Left" 
                                            VerticalAlignment   ="Center"
                                            IsHitTestVisible    ="False"
                                            >

                                            <ContentPresenter.Content>

                                                <Grid
                                                    Width    ="180"
                                                    >

                                                    <Grid.ColumnDefinitions>

                                                        <ColumnDefinition
                                                            Width   ="180"
                                                            />

                                                    </Grid.ColumnDefinitions>

                                                        <TextBlock
                                                            Grid.Column         ="0"
                                                            Margin              ="10,0,0,0"
                                                            Text                ="{TemplateBinding SelectionBoxItem, Converter={StaticResource TextConverter}}"
                                                            TextTrimming        ="CharacterEllipsis"
                                                            VerticalAlignment   ="Center"
                                                            Foreground          ="Black"                                                                
                                                            />

                                                    </Grid>

                                            </ContentPresenter.Content>

                                        </ContentPresenter>

                                        <!-- The ToggleButton is databound to the ComboBox itself to toggle IsDropDownOpen -->
                                        <ToggleButton 
                                            x:Name          ="ToggleButton" 
                                            Template        ="{DynamicResource ComboBoxToggleButton}" 
                                            Focusable       ="false" 
                                            IsChecked       ="{Binding Path=IsDropDownOpen, 
                                                                       Mode =TwoWay, 
                                                                       RelativeSource  ={RelativeSource TemplatedParent}}" 
                                            ClickMode       ="Press"
                                            Margin          ="16,5,2,2"                                           
                                            />

                                    </Grid>

                                </Border>

                            </Border>

                            <!-- The Popup shows the list of items in the 
                            ComboBox. IsOpen is databound to IsDropDownOpen 
                            which is toggled via the ComboBoxToggleButton -->
                            <Popup 
                                x:Name                                      ="PART_popup" 
                                IsOpen                                      ="{TemplateBinding IsDropDownOpen}" 
                                ScrollViewer.VerticalScrollBarVisibility    ="Auto"
                                Placement                                   ="Bottom" 
                                Focusable                                   ="False" 
                                MinWidth                                    ="{Binding ElementName=brd1, Path=ActualWidth}"
                                AllowsTransparency                          ="True" 
                                PopupAnimation                              ="None"                                  
                                MaxWidth                                    ="325"
                                >

                                <dropShadow:SystemDropShadowChrome 
                                    Visibility      ="Visible" 
                                    Margin          ="3"                                           
                                    >

                                    <Grid                                                    
                                        x:Name              ="DropDown"                                            
                                        SnapsToDevicePixels ="True"
                                        Margin               ="0,-1,0,0"  
                                        >

                                        <Grid.RowDefinitions>
                                            <RowDefinition
                                                Height="18"
                                                />
                                            <RowDefinition
                                                Height="*"
                                                />
                                            <RowDefinition
                                                Height="18"
                                                />
                                        </Grid.RowDefinitions>


                                        <Border 
                                            x:Name          ="DropDownBorder"
                                            Grid.Row="0"
                                            Grid.RowSpan="3"
                                            Background      ="{StaticResource dropDownBackground}"                                              
                                            BorderBrush     ="{DynamicResource SolidBorderBrush}" 
                                            BorderThickness ="1"
                                            />

                                        <RepeatButton
                                            x:Name      ="upRepeatButton"
                                            Grid.Row    ="0"
                                            Margin      ="1,0"
                                            ClickMode   ="Press"
                                            Style       ="{DynamicResource ScrollBarLineButton}"
                                            Height      ="18"                       
                                            Content     ="M 0 4 L 8 4 L 4 0 Z"
                                            />

                                        <ScrollViewer 
                                            Name                            ="scrollCombo"
                                            Margin                          ="1,0,1,0"
                                            Style                           ="{DynamicResource ComboBoxScrollViewerStyle}"                                          
                                            Grid.Row                        ="1"
                                            SnapsToDevicePixels             ="True" 
                                            HorizontalScrollBarVisibility   ="Hidden" 
                                            VerticalScrollBarVisibility     ="Hidden" 
                                            CanContentScroll                ="False"
                                            HorizontalAlignment             ="Stretch"
                                            Focusable                       ="False"
                                            >

                                            <ItemsPresenter
                                                Margin="0,18"
                                                />


                                        </ScrollViewer>

                                        <RepeatButton
                                            x:Name      ="downRepeatButton"
                                            Grid.Row    ="2"
                                            Margin      ="1,0"
                                            ClickMode   ="Press"
                                            Style       ="{StaticResource ScrollBarLineButton}"
                                            Height      ="18"                        
                                            Content     ="M 0 0 L 4 4 L 8 0 Z"
                                            />

                                    </Grid>

                                </dropShadow:SystemDropShadowChrome>

                            </Popup>

                        </Grid>

                        <ControlTemplate.Triggers>

                            <!-- This forces the DropDown to have a minimum
                            size if it is empty -->
                            <Trigger
                                Property    ="HasItems"
                                Value       ="false"
                                >

                                <Setter
                                    Property    ="MinHeight"
                                    Value       ="95"
                                    TargetName  ="DropDownBorder"
                                    />

                            </Trigger>

                            <Trigger
                                Property    ="IsGrouping"
                                Value       ="True"
                                >

                                <Setter
                                    Property    ="ScrollViewer.CanContentScroll"
                                    Value       ="false"
                                    />

                            </Trigger>

                        </ControlTemplate.Triggers>

                    </ControlTemplate>

                </Setter.Value>

            </Setter>

        </Style>        

有关于此的任何想法吗？