How to hide a part of a WPF control

Question

Is it possible to hide a part of a WPF control? .NET 4 has a DatePicker which renders 4 parts, according to MSDN. Is it possible to hide (in my case) the TextBox part (probably named PART_TextBox)?

I have seen examples of styling the DatePicker completely, and it involves alot of XAML, when all I want to do is hide one part of the control.

Answer 1

Why not add Visibility="Collapsed" to the relevant TextBox in the default style?

<Style TargetType="controls:DatePicker">
    <Setter Property="IsTabStop" Value="False" />
    <Setter Property="Background" Value="#FFFFFFFF" />
    <Setter Property="Padding" Value="2" />
    <Setter Property="SelectionBackground" Value="#FF444444" />
    <Setter Property="BorderBrush">
        <Setter.Value>
            <LinearGradientBrush EndPoint=".5,0" StartPoint=".5,1">
                <GradientStop Color="#FF617584" Offset="0" />
                <GradientStop Color="#FF718597" Offset="0.375" />
                <GradientStop Color="#FF8399A9" Offset="0.375" />
                <GradientStop Color="#FFA3AEB9" Offset="1" />
            </LinearGradientBrush>
        </Setter.Value>
    </Setter>
    <Setter Property="BorderThickness" Value="1" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="controls:DatePicker">
                <Grid x:Name="Root">
                    <Grid.Resources>
                        <!-- Main DatePicker Brushes -->
                        <SolidColorBrush x:Key="DisabledBrush" Color="#8CFFFFFF" />

                        <!-- Button Template -->
                        <ControlTemplate x:Key="DropDownButtonTemplate" TargetType="Button">
                            <Grid FlowDirection="LeftToRight">
                                <vsm:VisualStateManager.VisualStateGroups>
                                    <vsm:VisualStateGroup x:Name="CommonStates">
                                        <vsm:VisualStateGroup.Transitions>
                                            <vsm:VisualTransition GeneratedDuration="0" />
                                            <vsm:VisualTransition To="MouseOver" GeneratedDuration="0:0:0.1" />
                                            <vsm:VisualTransition To="Pressed" GeneratedDuration="0:0:0.1" />
                                        </vsm:VisualStateGroup.Transitions>
                                        <vsm:VisualState x:Name="Normal" />
                                        <vsm:VisualState x:Name="MouseOver">
                                            <Storyboard>
                                                <ColorAnimation Duration="0" Storyboard.TargetName="Background" Storyboard.TargetProperty="(Border.Background).(SolidColorBrush.Color)" To="#FF448DCA" />
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Border.Background).(GradientBrush.GradientStops)[3].(GradientStop.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#7FFFFFFF" />
                                                </ColorAnimationUsingKeyFrames>
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Border.Background).(GradientBrush.GradientStops)[2].(GradientStop.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#CCFFFFFF" />
                                                </ColorAnimationUsingKeyFrames>
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Border.Background).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#F2FFFFFF" />
                                                </ColorAnimationUsingKeyFrames>
                                            </Storyboard>
                                        </vsm:VisualState>
                                        <vsm:VisualState x:Name="Pressed">
                                            <Storyboard>
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="Background" Storyboard.TargetProperty="(Border.Background).(SolidColorBrush.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#FF448DCA" />
                                                </ColorAnimationUsingKeyFrames>
                                                <DoubleAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="Highlight" Storyboard.TargetProperty="(UIElement.Opacity)">
                                                    <SplineDoubleKeyFrame KeyTime="0" Value="1" />
                                                </DoubleAnimationUsingKeyFrames>
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Border.Background).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#EAFFFFFF" />
                                                </ColorAnimationUsingKeyFrames>
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Border.Background).(GradientBrush.GradientStops)[2].(GradientStop.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#C6FFFFFF" />
                                                </ColorAnimationUsingKeyFrames>
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Border.Background).(GradientBrush.GradientStops)[3].(GradientStop.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#6BFFFFFF" />
                                                </ColorAnimationUsingKeyFrames>
                                                <ColorAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Border.Background).(GradientBrush.GradientStops)[0].(GradientStop.Color)">
                                                    <SplineColorKeyFrame KeyTime="0" Value="#F4FFFFFF" />
                                                </ColorAnimationUsingKeyFrames>
                                            </Storyboard>
                                        </vsm:VisualState>
                                        <vsm:VisualState x:Name="Disabled">
                                            <Storyboard>
                                                <DoubleAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="DisabledVisual" Storyboard.TargetProperty="(UIElement.Opacity)">
                                                    <SplineDoubleKeyFrame KeyTime="0" Value="1" />
                                                </DoubleAnimationUsingKeyFrames>
                                            </Storyboard>
                                        </vsm:VisualState>
                                    </vsm:VisualStateGroup>
                                </vsm:VisualStateManager.VisualStateGroups>

                                <!--Start UI-->
                                <Grid Height="18" Width="19" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0" Background="#11FFFFFF">
                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition Width="20*" />
                                        <ColumnDefinition Width="20*" />
                                        <ColumnDefinition Width="20*" />
                                        <ColumnDefinition Width="20*" />
                                    </Grid.ColumnDefinitions>
                                    <Grid.RowDefinitions>
                                        <RowDefinition Height="23*" />
                                        <RowDefinition Height="19*" />
                                        <RowDefinition Height="19*" />
                                        <RowDefinition Height="19*" />
                                    </Grid.RowDefinitions>
                                    <Border Margin="-1" Grid.ColumnSpan="4" Grid.Row="0" Grid.RowSpan="4" BorderThickness="1" BorderBrush="#FF6DBDD1" Opacity="0" CornerRadius="0,0,1,1" x:Name="Highlight" />
                                    <Border x:Name="Background" Margin="0,-1,0,0" Grid.ColumnSpan="4" Grid.Row="1" Grid.RowSpan="3" BorderThickness="1" BorderBrush="#FFFFFFFF" Opacity="1" CornerRadius=".5" Background="#FF1F3B53" />
                                    <Border x:Name="BackgroundGradient" Margin="0,-1,0,0" Grid.ColumnSpan="4" Grid.Row="1" Grid.RowSpan="3" BorderThickness="1" BorderBrush="#BF000000" Opacity="1" CornerRadius=".5">
                                        <Border.Background>
                                            <LinearGradientBrush StartPoint=".7,0" EndPoint=".7,1">
                                                <GradientStop Color="#FFFFFFFF" Offset="0" />
                                                <GradientStop Color="#F9FFFFFF" Offset="0.375" />
                                                <GradientStop Color="#E5FFFFFF" Offset="0.625" />
                                                <GradientStop Color="#C6FFFFFF" Offset="1" />
                                            </LinearGradientBrush>
                                        </Border.Background>
                                    </Border>
                                    <Rectangle Grid.ColumnSpan="4" Grid.RowSpan="1" StrokeThickness="1">
                                        <Rectangle.Stroke>
                                            <LinearGradientBrush EndPoint="0.48,-1" StartPoint="0.48,1.25">
                                                <GradientStop Color="#FF494949" />
                                                <GradientStop Color="#FF9F9F9F" Offset="1" />
                                            </LinearGradientBrush>
                                        </Rectangle.Stroke>
                                        <Rectangle.Fill>
                                            <LinearGradientBrush EndPoint="0.3,-1.1" StartPoint="0.46,1.6">
                                                <GradientStop Color="#FF4084BD" />
                                                <GradientStop Color="#FFAFCFEA" Offset="1" />
                                            </LinearGradientBrush>
                                        </Rectangle.Fill>
                                    </Rectangle>
                                    <Path HorizontalAlignment="Center" Margin="4,3,4,3" VerticalAlignment="Center" RenderTransformOrigin="0.5,0.5" Grid.Column="0" Grid.Row="1" Fill="#FF2F2F2F" Stretch="Fill" Data="M11.426758,8.4305077 L11.749023,8.4305077 L11.749023,16.331387 L10.674805,16.331387 L10.674805,10.299648 L9.0742188,11.298672 L9.0742188,10.294277 C9.4788408,10.090176 9.9094238,9.8090878 10.365967,9.4510155 C10.82251,9.0929432 11.176106,8.7527733 11.426758,8.4305077 z M14.65086,8.4305077 L18.566387,8.4305077 L18.566387,9.3435936 L15.671368,9.3435936 L15.671368,11.255703 C15.936341,11.058764 16.27293,10.960293 16.681133,10.960293 C17.411602,10.960293 17.969301,11.178717 18.354229,11.615566 C18.739157,12.052416 18.931622,12.673672 18.931622,13.479336 C18.931622,15.452317 18.052553,16.438808 16.294415,16.438808 C15.560365,16.438808 14.951641,16.234707 14.468243,15.826504 L14.881817,14.929531 C15.368796,15.326992 15.837872,15.525723 16.289043,15.525723 C17.298809,15.525723 17.803692,14.895514 17.803692,13.635098 C17.803692,12.460618 17.305971,11.873379 16.310528,11.873379 C15.83071,11.873379 15.399232,12.079271 15.016094,12.491055 L14.65086,12.238613 z" Grid.ColumnSpan="4" Grid.RowSpan="3" />
                                    <Ellipse HorizontalAlignment="Center" VerticalAlignment="Center" Fill="#FFFFFFFF" StrokeThickness="0" Grid.ColumnSpan="4" Width="3" Height="3" />
                                    <Border Grid.ColumnSpan="4" Grid.Row="0" Grid.RowSpan="4" BorderThickness="1" BorderBrush="#B2FFFFFF" Opacity="0" CornerRadius="0,0,.5,.5" x:Name="DisabledVisual" />
                                </Grid>
                                <!--End UI-->
                            </Grid>
                        </ControlTemplate>
                    </Grid.Resources>
                    <vsm:VisualStateManager.VisualStateGroups>
                        <vsm:VisualStateGroup x:Name="CommonStates">
                            <vsm:VisualState x:Name="Normal" />
                            <vsm:VisualState x:Name="Disabled">
                                <Storyboard>
                                    <DoubleAnimation Storyboard.TargetName="DisabledVisual" Storyboard.TargetProperty="Opacity" To="1" Duration="0" />
                                </Storyboard>
                            </vsm:VisualState>
                        </vsm:VisualStateGroup>
                        <vsm:VisualStateGroup x:Name="ValidationStates">
                            <vsm:VisualState x:Name="Valid" />
                            <vsm:VisualState x:Name="InvalidUnfocused">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ValidationErrorElement" Storyboard.TargetProperty="Visibility">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility>Visible</Visibility>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </vsm:VisualState>
                            <vsm:VisualState x:Name="InvalidFocused">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ValidationErrorElement" Storyboard.TargetProperty="Visibility">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility>Visible</Visibility>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="validationTooltip" Storyboard.TargetProperty="IsOpen">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <system:Boolean>True</system:Boolean>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </vsm:VisualState>
                        </vsm:VisualStateGroup>
                    </vsm:VisualStateManager.VisualStateGroups>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <controlsPrimitives:DatePickerTextBox x:Name="TextBox" SelectionBackground="{TemplateBinding SelectionBackground}" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Column="0" Visibility="Collapsed" />
                    <Border x:Name="ValidationErrorElement" Grid.Column="0" BorderThickness="1" CornerRadius="1" BorderBrush="#FFDB000C" Visibility="Collapsed">
                        <ToolTipService.ToolTip>
                            <ToolTip x:Name="validationTooltip" Template="{StaticResource CommonValidationToolTipTemplate}" Placement="Right" PlacementTarget="{Binding ElementName=TextBox}" DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
                                <ToolTip.Triggers>
                                    <EventTrigger RoutedEvent="Canvas.Loaded">
                                        <EventTrigger.Actions>
                                            <BeginStoryboard>
                                                <Storyboard>
                                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="validationTooltip" Storyboard.TargetProperty="IsHitTestVisible">
                                                        <DiscreteObjectKeyFrame KeyTime="0">
                                                            <DiscreteObjectKeyFrame.Value>
                                                                <system:Boolean>true</system:Boolean>
                                                            </DiscreteObjectKeyFrame.Value>
                                                        </DiscreteObjectKeyFrame>
                                                    </ObjectAnimationUsingKeyFrames>
                                                </Storyboard>
                                            </BeginStoryboard>
                                        </EventTrigger.Actions>
                                    </EventTrigger>
                                </ToolTip.Triggers>
                            </ToolTip>
                        </ToolTipService.ToolTip>
                        <Grid Width="12" Height="12" HorizontalAlignment="Right" Margin="1,-4,-4,0" VerticalAlignment="Top" Background="Transparent">
                            <Path Margin="1,3,0,0" Data="M 1,0 L6,0 A 2,2 90 0 1 8,2 L8,7 z" Fill="#FFDC000C" />
                            <Path Margin="1,3,0,0" Data="M 0,0 L2,0 L 8,6 L8,8" Fill="#FFFFFF" />
                        </Grid>
                    </Border>                        
                    <Button x:Name="Button" Template="{StaticResource DropDownButtonTemplate}" Grid.Column="1" Width="20" Foreground="{TemplateBinding Foreground}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Margin="2,0,2,0" />
                    <Grid x:Name="DisabledVisual" Opacity="0" IsHitTestVisible="False" Grid.ColumnSpan="2">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*" />
                            <ColumnDefinition Width="Auto" />
                        </Grid.ColumnDefinitions>
                        <Rectangle RadiusX="1" RadiusY="1" Fill="#8CFFFFFF" />
                        <Rectangle RadiusX="1" RadiusY="1" Fill="#8CFFFFFF" Grid.Column="1" Height="18" Width="19" Margin="2,0,2,0" />
                    </Grid>
                    <Popup x:Name="Popup" />
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Answer 2

Well, I have a solution for your case :)

class MyDateTimePicker : DatePicker
{
    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        var textBox = this.Template.FindName("PART_TextBox", this) as UIElement;
        if (textBox != null)
        {
            textBox.Visibility = Visibility.Hidden;
        }
    }
}

Answer 3

You could change the default Button Style to be Visibility.Collapsed. For example, if you wanted to hide the Buttons for 2 DatePickers in a Grid you could do as follows:

<Grid.Resources>
     <Style TargetType="{x:Type Button}">
           <Setter Property="Visibility" Value="Collapsed"/>
     </Style>
</Grid.Resources>

XAML only solution w/o inheritance ...

Answer 4

You can do it all in XAML with behaviors and the TemplatePartAction I wrote:

    <DatePicker>
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="Loaded">
                <local:TemplatePartAction TemplatePartName="TextBox">
                    <ei:ChangePropertyAction PropertyName="Visibility" Value="Collapsed"/>
                </local:TemplatePartAction>
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </DatePicker>

and here is the TemplatePart functionality:

public class TemplatePartHelper<T> where T : IAttachedObject
{
    public IAttachedObject Parent { get; set; }
    public List<T> Children { get; private set; }
    public string Name { get; set; }
    public Control TemplatePart { get; set; }

    public TemplatePartHelper(IAttachedObject parent)
    {
        Parent = parent;
        Children = new List<T>();
    }

    public void AssociateChildren()
    {
        if (TemplatePart != null)
            return;
        var control = Parent.AssociatedObject as Control;
        var template = control.Template;
        if (template == null)
            return;
        var partName = "PART_" + Name;
        TemplatePart = template.FindName(partName, control) as Control;
        if (TemplatePart == null)
            return;
        foreach (var child in Children)
            child.Attach(TemplatePart);
    }
}

[ContentProperty("Behaviors")]
public class TemplatePartBehavior : Behavior<Control>
{
    public TemplatePartHelper<Behavior> Helper { get; private set; }
    public List<Behavior> Behaviors { get { return Helper.Children; } }
    public string TemplatePartName { get { return Helper.Name; } set { Helper.Name = value; } }

    public TemplatePartBehavior()
    {
        Helper = new TemplatePartHelper<Behavior>(this);
    }

    protected override void OnAttached()
    {
        AssociatedObject.Initialized += (s, e) => Helper.AssociateChildren();
        AssociatedObject.Loaded += (s, e) => Helper.AssociateChildren();
    }
}

[ContentProperty("Actions")]
public class TemplatePartAction : TriggerAction<Control>
{
    public TemplatePartHelper<TriggerAction> Helper { get; private set; }
    public List<TriggerAction> Actions { get { return Helper.Children; } }
    public string TemplatePartName { get { return Helper.Name; } set { Helper.Name = value; } }

    public TemplatePartAction()
    {
        Helper = new TemplatePartHelper<TriggerAction>(this);
    }

    protected override void OnAttached()
    {
        AssociatedObject.Loaded += (s, e) => Helper.AssociateChildren();
    }

    protected override void Invoke(object parameter)
    {
        foreach (var action in Actions)
        {
            if (action.IsEnabled)
            {
                var methodInfo = typeof(TriggerAction).GetMethod("Invoke", BindingFlags.Instance | BindingFlags.NonPublic, null, new Type[] { typeof(object) }, null);
                methodInfo.Invoke(action, new object[] { parameter });
            }
        }
    }
}

If you are not familiar with behaviors, Install the Expression Blend 4 SDK and add these namespaces:

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"

and add System.Windows.Interactivity and Microsoft.Expression.Interactions to your project.