Customized Datepicker does not popup calendar - wpf

Question

I have customized datepicker style, but for some reason when i click on the datepicker, the calendar does not popup and does not activate the mouseup subroutine.
If I change the Button x:Name="Button" to Button x:Name="PART_Button" the calendar will popup, but the TextBlocks Content will show:"Show Calendar"
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:controls="clr-namespace:System.Windows.Controls;assembly=PresentationFramework"
xmlns:iPodConv="clr-namespace:Custom_DatePicker.CustomDateConverter"
xmlns:vsm="clr-namespace:System.Windows;assembly=PresentationFramework">
<Style x:Key="CustomDatePickerStyle" 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="PART_Root">
<Grid.Resources>
<SolidColorBrush x:Key="DisabledBrush" Color="#8CFFFFFF"/>
<ControlTemplate x:Key="DropDownButtonTemplate" TargetType="Button">
<Grid>
<vsm:VisualStateManager.VisualStateGroups>
<vsm:VisualStateGroup x:Name="CommonStates">
<vsm:VisualStateGroup.Transitions>
<vsm:VisualTransition GeneratedDuration="0"/>
<vsm:VisualTransition GeneratedDuration="0:0:0.1" To="MouseOver"/>
<vsm:VisualTransition GeneratedDuration="0:0:0.1" To="Pressed"/>
</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>
<Grid Height="48" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center" Width="59" Background="#11FFFFFF">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="6*"/>
<ColumnDefinition Width="30*"/>
<ColumnDefinition Width="30*"/>
<ColumnDefinition Width="30*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="6*"/>
<RowDefinition Height="20*"/>
<RowDefinition Height="20*"/>
<RowDefinition Height="30*"/>
</Grid.RowDefinitions>
<Border x:Name="Highlight" Margin="-1" Opacity="0" Grid.ColumnSpan="4" Grid.Row="0" Grid.RowSpan="4" BorderBrush="#FF6DBDD1" BorderThickness="1" CornerRadius="0,0,1,1"/>
<Border x:Name="Background" Margin="0,-1,0,0" Opacity="1" Grid.ColumnSpan="4" Grid.Row="1" Grid.RowSpan="3" Background="#FF1F3B53" BorderBrush="#FFFFFFFF" BorderThickness="1" CornerRadius=".5"/>
<Border x:Name="BackgroundGradient" Margin="0,-1,0,0" Opacity="1" Grid.ColumnSpan="4" Grid.Row="1" Grid.RowSpan="3" BorderBrush="#BF000000" BorderThickness="1" CornerRadius=".5">
<Border.Background>
<LinearGradientBrush EndPoint=".7,1" StartPoint=".7,0">
<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 StrokeThickness="1" Grid.ColumnSpan="4" Grid.RowSpan="2" Margin="0,0,0,2">
<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="#FFBD4A40"/>
<GradientStop Color="#FFEAAFAF" Offset="1"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<TextBlock
HorizontalAlignment="Center"
VerticalAlignment="Center"
DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=.Content}"
Text="{Binding Converter={StaticResource DateTimeFormatter}, ConverterParameter=DOW}"
FontSize="11" Margin="0,0,0,3"
Grid.Column="0"
Grid.ColumnSpan="4"
Grid.Row="0"
Grid.RowSpan="2"
/>
<TextBlock
HorizontalAlignment="Center"
VerticalAlignment="Center"
DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Content}"
Text="{Binding Converter={StaticResource DateTimeFormatter}, ConverterParameter=MMMM}"
FontSize="10" Margin="0,10,0,3"
Grid.Column="0"
Grid.ColumnSpan="4"
Grid.Row="1"
Grid.RowSpan="2"
/>
<TextBlock
HorizontalAlignment="Center"
VerticalAlignment="Bottom"
DataContext="{Binding Path=Content, RelativeSource={RelativeSource TemplatedParent}}"
Text="{Binding Converter={StaticResource DateTimeFormatter}, ConverterParameter=dd}"
FontSize="26" Margin="0,0,0,-3"
Grid.Column="0"
Grid.ColumnSpan="4"
Grid.Row="2"
Grid.RowSpan="2" />
<Border x:Name="PART_DisabledVisual" Opacity="0" Grid.ColumnSpan="4" Grid.Row="0" Grid.RowSpan="4" BorderBrush="#B2FFFFFF" BorderThickness="1" CornerRadius="0,0,.5,.5"/>
</Grid>
</Grid>
</ControlTemplate>
</Grid.Resources>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<vsm:VisualStateManager.VisualStateGroups>
<vsm:VisualStateGroup x:Name="CommonStates">
<vsm:VisualState x:Name="Normal"/>
<vsm:VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimation Duration="0" Storyboard.TargetName="DisabledVisual" Storyboard.TargetProperty="Opacity" To="1"/>
</Storyboard>
</vsm:VisualState>
</vsm:VisualStateGroup>
</vsm:VisualStateManager.VisualStateGroups>
<Button x:Name="Button" Grid.Column="0" Grid.ColumnSpan="4"
Content="{TemplateBinding SelectedDate}"
Template="{StaticResource DropDownButtonTemplate}"
Margin="2,0,2,0"
Width="60"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Foreground="{TemplateBinding Foreground}"/>
<Grid x:Name="DisabledVisual" IsHitTestVisible="False" Opacity="0" Grid.ColumnSpan="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Rectangle Fill="#8CFFFFFF" RadiusX="1" RadiusY="1"/>
<Rectangle Fill="#8CFFFFFF" RadiusX="1" RadiusY="1" Height="18" Margin="2,0,2,0" Width="24" Grid.Column="1"/>
</Grid>
<Popup x:Name="PART_Popup"
PlacementTarget="{Binding ElementName=Button}"
Placement="Bottom"
StaysOpen="False"
AllowsTransparency="True"
PopupAnimation="Slide"
Focusable="True" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
Any help will be appreciated.

Answer 1

If you take out named parts (i.e. controls with names that start with "PART_") then you will usually lose some functionality. In your case, the following code is in the OnApplyTemplate of the DatePicker:
this._dropDownButton = (base.GetTemplateChild("PART_Button") as Button);
if (this._dropDownButton != null)
{
this._dropDownButton.Click += new RoutedEventHandler(this.DropDownButton_Click);
this._dropDownButton.AddHandler(UIElement.MouseLeaveEvent, new MouseEventHandler(this.DropDownButton_MouseLeave), true);
if (this._dropDownButton.Content == null)
{
this._dropDownButton.Content = SR.Get("DatePicker_DropDownButtonName");
}
}
You can see that the DatePicker sets the content, if null, and registers a click handler. The latter of which opens the popup.
Now, when OnApplyTemplate is called SelectedDate is probably null, so that's why the DatePicker sets the content of the button. You would need to ensure that the SelectedDate is not null to prevent DatePicker from setting Content.
One way might be use something like {Binding RelativeSource={RelativeSource TemplatedParent}, Path=SelectedDate, TargetNullValue="1/1/2011"}, but you may need to use the long syntax:
xmlns:system="clr-namespace:System;assembly=mscorlib"
<!-- ... -->
<Binding RelativeSource="{RelativeSource TemplatedParent}" Path="SelectedDate">
<Binding.TargetNullValue>
<system:DateTime>1/1/2011</system:DateTime>
</Binding.TargetNullValue>
</Binding>