Question

Is it possible to update a templated AutoCompleteBox’s BorderBrush at runtime? I can’t seem to set the BorderBrush or the background.

Even base statements like TxtFoodSearch.BorderBrush = new SolidColorBrush(Colors.Red) don’t seem to made a difference after the page has loaded.

My Xaml is below.

                <controls:AutoCompleteBox x:Name='MyAutoCompleteSample' Margin='17,24,58,32' FontSize='12'>                 <controls:AutoCompleteBox.Style>                     <Style TargetType='controls:AutoCompleteBox'>                         <Setter Property='IsTabStop' Value='False' />                         <Setter Property='Template'>                             <Setter.Value>                                 <ControlTemplate TargetType='controls:AutoCompleteBox'>                                     <Grid Margin='{TemplateBinding Padding}'                      Background='{TemplateBinding Background}'>                                         <TextBox IsTabStop='True' x:Name='Text' Style='{TemplateBinding TextBoxStyle}' Margin='0'                                          KeyDown='MyAutoCompleteSample_KeyDown'                                         />                                         <Popup x:Name='Popup'>                                             <Border x:Name='PopupBorder' HorizontalAlignment='Stretch' Opacity='0.0' BorderThickness='0' CornerRadius='3'>                                                 <Border.RenderTransform>                                                     <TranslateTransform X='1' Y='1' />                                                 </Border.RenderTransform>                                                 <Border.Background>                                                     <SolidColorBrush Color='#11000000' />                                                 </Border.Background>                                                 <Border                                HorizontalAlignment='Stretch'                                Opacity='1.0'                                Padding='0'                                ToolTipService.ToolTip='Select or enter your food selection'                                BorderThickness='{TemplateBinding BorderThickness}'                                BorderBrush='{TemplateBinding BorderBrush}'                                CornerRadius='3'>                                                     <Border.RenderTransform>                                                         <TransformGroup>                                                             <TranslateTransform X='-1' Y='-1' />                                                         </TransformGroup>                                                     </Border.RenderTransform>                                                     <Border.Background>                                                         <LinearGradientBrush EndPoint='0.5,1' StartPoint='0.5,0'>                                                             <GradientStop Color='#FFDDDDDD' Offset='0'/>                                                             <GradientStop Color='#AADDDDDD' Offset='1'/>                                                         </LinearGradientBrush>                                                     </Border.Background>                                                     <ListBox                                        x:Name='SelectionAdapter'                                        ScrollViewer.HorizontalScrollBarVisibility='Auto'                                        ScrollViewer.VerticalScrollBarVisibility='Auto'                                        ItemContainerStyle='{TemplateBinding ItemContainerStyle}'                                        ItemTemplate='{TemplateBinding ItemTemplate}' />                                                 </Border>                                             </Border>                                         </Popup>                                         <VisualStateManager.VisualStateGroups>                                             <VisualStateGroup x:Name='PopupStates'>                                                 <VisualStateGroup.Transitions>                                                     <VisualTransition GeneratedDuration='0:0:0.1' To='PopupOpened' />                                                     <VisualTransition GeneratedDuration='0:0:0.2' To='PopupClosed' />                                                 </VisualStateGroup.Transitions>                                                 <VisualState x:Name='PopupOpened'>                                                     <Storyboard>                                                         <DoubleAnimation Storyboard.TargetName='PopupBorder' Storyboard.TargetProperty='Opacity' To='1.0' />                                                     </Storyboard>                                                 </VisualState>                                                 <VisualState x:Name='PopupClosed'>                                                     <Storyboard>                                                         <DoubleAnimation Storyboard.TargetName='PopupBorder' Storyboard.TargetProperty='Opacity' To='0.0' />                                                     </Storyboard>                                                 </VisualState>                                             </VisualStateGroup>                                         </VisualStateManager.VisualStateGroups>                                     </Grid>                                 </ControlTemplate>                             </Setter.Value>                         </Setter>                     </Style>                 </controls:AutoCompleteBox.Style>             </controls:AutoCompleteBox> 

Answer 1

One way I’ve managed to find how to address the styling through code is the following.

Walk the visual tree and get the AutoCompleteBox, cast that into a textbox, then adjust the colors (border, background, etc)

//Cast into textbox TextBox Temp = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(MyAutoCompleteControl, 0), 0) as TextBox;  Temp.BorderBrush = new SolidColorBrush(Colors.Red);//Change border color 

I’m sure there is a better way, but this seems to work.