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DropDownButton - Position and size on drop down menu

Apr 2, 2012 at 4:11 PM
Edited Apr 2, 2012 at 4:12 PM

Can I modify the position the drop down menu will appear and can I somehow decide the size?

I have a ListBox on the side of this DropDownButton and I want it to cover the size and position of these two controls.

Best regards,

Gabriel Paulsson

Coordinator
Apr 3, 2012 at 9:42 PM

There is no property that allows you to configure the position and the size of the drop down menu,  However, you may be able to achieve what you want if you assign a ControlTemplate in the DropDownButton.Template property.

 

Here is the XAML of my sample:

<Window x:Class="Sample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
        xmlns:conv="clr-namespace:Xceed.Wpf.Toolkit.Core.Converters;assembly=WPFToolkit.Extended"
        xmlns:chrome="clr-namespace:Xceed.Wpf.Toolkit.Chromes;assembly=WPFToolkit.Extended"
        Title="MainWindow"
        FontSize="24">
   <Window.Resources>
      <conv:InverseBoolConverter x:Key="InverseBoolConverter" />

      <LinearGradientBrush x:Key="PopupDarkBorderBrush" EndPoint="0.5,1" StartPoint="0.5,0">
         <GradientStop Color="#FFA3AEB9" Offset="0" />
         <GradientStop Color="#FF8399A9" Offset="0.375" />
         <GradientStop Color="#FF718597" Offset="0.375" />
         <GradientStop Color="#FF617584" Offset="1" />
      </LinearGradientBrush>

      <LinearGradientBrush x:Key="PopupBackgroundBrush" StartPoint="0,0" EndPoint="0,1">
         <LinearGradientBrush.GradientStops>
            <GradientStopCollection>
               <GradientStop Offset="0" Color="#FFffffff" />
               <GradientStop Offset="1" Color="#FFE8EBED" />
            </GradientStopCollection>
         </LinearGradientBrush.GradientStops>
      </LinearGradientBrush>

      <Style x:Key="DropDownButtonStyle"
             TargetType="{x:Type xctk:DropDownButton}">
         <Setter Property="BorderThickness" Value="1" />
         <Setter Property="IsTabStop" Value="False" />
         <Setter Property="HorizontalContentAlignment" Value="Center" />
         <Setter Property="VerticalContentAlignment" Value="Center" />
         <Setter Property="Padding" Value="3" />
         <Setter Property="Template">
            <Setter.Value>
               <ControlTemplate TargetType="{x:Type xctk:DropDownButton}">
                  <Grid x:Name="MainGrid" SnapsToDevicePixels="True">
                     <ToggleButton x:Name="PART_DropDownButton"
                                Grid.Column="1"
                                IsChecked="{Binding IsOpen, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
                                IsHitTestVisible="{Binding IsOpen, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource InverseBoolConverter}}">
                        <ToggleButton.Template>
                           <ControlTemplate TargetType="ToggleButton">
                              <ContentPresenter />
                           </ControlTemplate>
                        </ToggleButton.Template>
                        <Grid>
                           <chrome:ButtonChrome x:Name="ToggleButtonChrome"
                                             CornerRadius="2.75"
                                             RenderChecked="{TemplateBinding IsOpen}"
                                             RenderEnabled="{TemplateBinding IsEnabled}"
											            RenderMouseOver="{Binding IsMouseOver, ElementName=PART_DropDownButton}"
											            RenderPressed="{Binding IsPressed, ElementName=PART_DropDownButton}">
                              <Grid>
                                 <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="*" />
                                    <ColumnDefinition Width="Auto" />
                                 </Grid.ColumnDefinitions>
                                 <ContentPresenter Margin="{TemplateBinding Padding}" Content="{TemplateBinding Content}" ContentTemplate="{TemplateBinding ContentTemplate}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" RecognizesAccessKey="true" />
                                 <Grid x:Name="arrowGlyph" IsHitTestVisible="False" Margin="4,3,4,3" Grid.Column="1">
                                    <Path Width="7" Height="4" Data="M 0,1 C0,1 0,0 0,0 0,0 3,0 3,0 3,0 3,1 3,1 3,1 4,1 4,1 4,1 4,0 4,0 4,0 7,0 7,0 7,0 7,1 7,1 7,1 6,1 6,1 6,1 6,2 6,2 6,2 5,2 5,2 5,2 5,3 5,3 5,3 4,3 4,3 4,3 4,4 4,4 4,4 3,4 3,4 3,4 3,3 3,3 3,3 2,3 2,3 2,3 2,2 2,2 2,2 1,2 1,2 1,2 1,1 1,1 1,1 0,1 0,1 z" Fill="#FF000000" />
                                 </Grid>
                              </Grid>
                           </chrome:ButtonChrome>
                        </Grid>
                     </ToggleButton>

                     <Popup x:Name="PART_Popup" 
                         AllowsTransparency="True"
                         StaysOpen="False"
                         Placement="Relative"
                         PlacementTarget="{Binding ElementName=_coverRegion}"
                         MinWidth="{Binding ActualWidth, ElementName=_coverRegion}"
                         MaxWidth="{Binding ActualHeight, ElementName=_coverRegion}"
                         Focusable="False"
                         IsOpen="{Binding IsChecked, ElementName=PART_DropDownButton}">
                        <Border BorderThickness="1" Background="{StaticResource PopupBackgroundBrush}" BorderBrush="{StaticResource PopupDarkBorderBrush}">
                           <ContentPresenter Content="{TemplateBinding DropDownContent}" />
                        </Border>
                     </Popup>

                  </Grid>
               </ControlTemplate>
            </Setter.Value>
         </Setter>
      </Style>
   </Window.Resources>

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

      <TextBlock Grid.Row="0"
                 Padding="10"
                 TextAlignment="Center"
                 Text="Click in this region to close the drop down menu." />

      <Grid x:Name="_coverRegion"
            Grid.Row="1">
         <Grid.ColumnDefinitions>
            <ColumnDefinition />
            <ColumnDefinition />
         </Grid.ColumnDefinitions>

         <xctk:DropDownButton Grid.Column="0"
                              VerticalAlignment="Top"
                              Content="Click Me"
                              Style="{StaticResource DropDownButtonStyle}">
            <xctk:DropDownButton.DropDownContent>
               <xctk:ColorCanvas />
            </xctk:DropDownButton.DropDownContent>
         </xctk:DropDownButton>

         <TextBlock Grid.Column="1"
                    Padding="10"
                    TextAlignment="Justify"
                    Text="This text will be covered by the drop down menu." />
      </Grid>
   </Grid>
</Window>

 

The ControlTemplate I used is mostly a copy of the DropDownButton's default ControlTemplate.  The named part "PART_Popup" is the part you will need to customize.  In my sample, I set the MinWidth, MinHeight, HorizontalOffset, VerticalOffset, Placement and PlacementTarget properties to position the drop down menu and to cover the target region.