Develop Reference

WPF combobox prevent selection update

I've got a ComboBox that looks like this:
I don't want the value of ... to change when one of the items is selected.
I've tried a ton of different solutions - various bindings on SelectedIndex, SelectedValue, SelectionChanged, playing with IsEditable, IsReadonly, IsHitTestVisible, making ... an actual item, making it placeholder text, etc, etc, etc.
Every time I select an item, the ... updates with the child value. I want it to stay the same.
How can I prevent the combobox from automatically updating the text on selection, but still have it able to select a choice?
If it helps, here's the custom template for that image:
<ResourceDictionary
x:Class="ComboBoxA"
xmlns:local="clr-namespace:MyTemplates"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ControlTemplate x:Key="ComboBoxA" TargetType="{x:Type ComboBox}">
<Grid>
<ToggleButton
ClickMode="Press"
Focusable="false"
IsChecked="{Binding Path=IsDropDownOpen,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}"
Name="ToggleButton"
>
<ToggleButton.Template>
<ControlTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="36" />
</Grid.ColumnDefinitions>
<Border
x:Name="Border"
Grid.ColumnSpan="2"
CornerRadius="0"
BorderThickness="1" />
<Border
Grid.Column="0"
CornerRadius="0"
Margin="1"
Background="Transparent"
BorderThickness="0"
/>
<Path
x:Name="Arrow"
Grid.Column="1"
Fill="#707070"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Visibility="Collapsed"
Data="M0,0 L8,0 L4,4 z"
/>
<TextBlock
Margin="4,6"
Foreground="#282828"
Grid.Column="0"
Text="{Binding Path=(local:ComboBoxAHelper.Placeholder), RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}"
/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</Trigger>
<Trigger Property="ToggleButton.IsChecked" Value="true">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</Trigger>
<DataTrigger Binding="{Binding Path=(local:ComboBoxAHelper.ShowBorders), RelativeSource={RelativeSource TemplatedParent}}" Value="True">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</ToggleButton.Template>
</ToggleButton>
<ContentPresenter
Content="{TemplateBinding SelectionBoxItem}"
ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
HorizontalAlignment="Left"
IsHitTestVisible="False"
Margin="3,3,23,3"
Name="ContentSite"
VerticalAlignment="Center"
/>
<Popup
AllowsTransparency="True"
Focusable="False"
IsOpen="{TemplateBinding IsDropDownOpen}"
Name="Popup"
PopupAnimation="Slide"
>
<Grid Name="DropDown"
MaxHeight="{TemplateBinding MaxDropDownHeight}"
MinWidth="{TemplateBinding ActualWidth}"
SnapsToDevicePixels="True"
>
<Border
Background="White"
BorderBrush="#d9d9d9"
BorderThickness="1"
x:Name="DropDownBorder"
/>
<ScrollViewer Margin="4,6" SnapsToDevicePixels="True">
<StackPanel
IsItemsHost="True"
KeyboardNavigation.DirectionalNavigation="Contained"
/>
</ScrollViewer>
</Grid>
<Popup.Style>
<Style TargetType="Popup">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=(local:ComboBoxAHelper.RightAlignPopup), RelativeSource={RelativeSource TemplatedParent}}" Value="True">
<Setter Property="Placement" Value="Left" />
<Setter Property="VerticalOffset" Value="{Binding ActualHeight, RelativeSource={RelativeSource TemplatedParent}}" />
<Setter Property="HorizontalOffset" Value="{Binding ActualWidth, RelativeSource={RelativeSource TemplatedParent}}" />
</DataTrigger>
</Style.Triggers>
</Style>
</Popup.Style>
</Popup>
</Grid>
</ControlTemplate>
<Style x:Key="ComboBoxAItem" TargetType="{x:Type TextBlock}">
<Setter Property="FontSize" Value="12" />
<Setter Property="Foreground" Value="#282828" />
<Setter Property="Padding" Value="4" />
</Style>
</ResourceDictionary>
...and its corresponding XAML:
<ComboBox
templates:ComboBoxAHelper.Placeholder="..."
templates:ComboBoxAHelper.RightAlignPopup="True"
templates:ComboBoxAHelper.ShowBorders="True"
HorizontalAlignment="Right"
IsReadOnly="True"
IsEditable="False"
SelectedValue="x:Null"
Template="{StaticResource ComboBoxA}"
>
<ComboBoxItem>
<TextBlock Style="{StaticResource ComboBoxAItem}">Close</TextBlock>
</ComboBoxItem>
<ComboBoxItem>
<TextBlock Style="{StaticResource ComboBoxAItem}">Delete</TextBlock>
</ComboBoxItem>
</ComboBox>

The trick was to remove
Content="{TemplateBinding SelectionBoxItem}"
from the template (both in general and also the code posted in the question).
Thanks to #shadow32's answer to my separate question https://stackoverflow.com/a/50805408/385273.

How to avoid error icon from WPF validation overlapping other elements

I'm working on a WPF app and want to implement validation.
For displaying error messages etc. i'm using a style for the TextBox:
<Style TargetType="{x:Type TextBox}">
<Setter Property="Height"
Value="25"/>
<Setter Property="VerticalAlignment"
Value="Top"/>
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<DockPanel LastChildFill="true">
<Border Background="Red"
DockPanel.Dock="right"
Margin="5,0,0,0"
Width="20"
Height="20"
CornerRadius="10"
ToolTip="{Binding ElementName=customAdorner, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">
<TextBlock Text="!"
VerticalAlignment="Center"
HorizontalAlignment="Center"
FontWeight="Bold"
Foreground="White">
</TextBlock>
</Border>
<AdornedElementPlaceholder Name="customAdorner"
VerticalAlignment="Center" >
<Border BorderBrush="Red"
BorderThickness="1" />
</AdornedElementPlaceholder>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
<!--Additional style trigger for changing the background color of the textbox-->
<Style.Triggers>
<Trigger Property="Validation.HasError"
Value="true">
<Setter Property="Background"
Value="LightPink"/>
</Trigger>
</Style.Triggers>
</Style>
When an error in one of my textboxes occurs, the textbox gets a red border and to the right a red dot with a white "!" appears.
Now the problem is that the red dot to the right is overlapping the neighbour element.
Is there a way to avoid that kind of thing?
You can download an example from here:
WPF validation example
Then choose the project "Validation_ValidationRule" as startproject.
Thanks in advance!

I have changed your Window.Resources
<Window.Resources>
<Style x:Key="myErrorTemplate" TargetType="Control">
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<DockPanel LastChildFill="True">
<Ellipse DockPanel.Dock="Right"
ToolTip="{Binding ElementName=myTextbox,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}"
Width="15" Height="15"
Margin="-25,0,0,0"
StrokeThickness="1" Fill="Red" >
<Ellipse.Stroke>
<LinearGradientBrush EndPoint="1,0.5" StartPoint="0,0.5">
<GradientStop Color="#FFFA0404" Offset="0"/>
<GradientStop Color="#FFC9C7C7" Offset="1"/>
</LinearGradientBrush>
</Ellipse.Stroke>
</Ellipse>
<TextBlock DockPanel.Dock="Right"
ToolTip="{Binding ElementName=myControl,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}"
Foreground="White"
FontSize="11pt"
Margin="-15,5,0,0" FontWeight="Bold">!
</TextBlock>
<Border BorderBrush="Red" BorderThickness="1">
<AdornedElementPlaceholder Name="myControl"/>
</Border>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="Validation.HasError" Value="true">
<Setter Property="ToolTip"
Value="{Binding RelativeSource={x:Static RelativeSource.Self},
Path=(Validation.Errors)[0].ErrorContent}"/>
</Trigger>
</Style.Triggers>
</Style>
<Style TargetType="TextBox" BasedOn="{StaticResource myErrorTemplate}" />
<Style TargetType="CheckBox" BasedOn="{StaticResource myErrorTemplate}" />
<Style TargetType="ComboBox" BasedOn="{StaticResource myErrorTemplate}" />
</Window.Resources>
Try to adapt this for your needs

CheckComboBox : How to prevent a combobox from closing after a selection is clicked?

I've got a combobox and it's populated with a bunch of checkboxes. I wish the user to be able to click multiple times before the combobox closes (or is closed by the user themselves). The problems right now is that each time a checkbox is clicked, the combobox closes, forcing the user who wants to select multiple options to re-open it several times.
I've found other questions on the same subject but those apply to Silverlight, Qt etc. comparing the tags.
I've tried setting StayOpenOnEdit but that didn't do the trick. As far I could see, there's no property addressing my issue. That creates a suspicion that I might be barning up the wrong component all together.
How do I prevent the combobox to close automatically after a click in a checkbox in it?
Is there a more suitable component for such task and, if so, what's its name?
Please note that even if the answer to #2 is "yes", I'm still curious of #1 for purely academic reasons.
I've played with toggle button and list box, as someone suggested in a post. However, the that led only to an always fully shown list of all the checkboxes with some greyish thing behind it (which I'm assuming is the toggler). Perhaps I did something less clever in the mark-up.
<ToggleButton HorizontalAlignment="Left"
Margin="550,62,0,0"
VerticalAlignment="Top"
Width="100">
<ListBox x:Name="listBox1"
HorizontalAlignment="Left"
Height="100"
VerticalAlignment="Top" Width="100">
<CheckBox x:Name="checkBox3" Content="CheckBox"/>
<CheckBox x:Name="checkBox4" Content="CheckBox"/>
</ListBox>
</ToggleButton>
The point is to achieve something like this but it needs to be a standard WPF control (the concatenated line of all selected items is nice but not a must). Also, I've read the complaints that the binding and handling is not fully developed yet and I feel a bit suspicious.

Using Exapander Control you can achieve multple item selection without closing popup after single selection.
For understanding please run this code separately.
xaml
<Window.Resources>
<ControlTemplate x:Key="ComboboxToggleButton" TargetType="{x:Type ToggleButton}">
<Grid Background="{Binding Background,RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="35" />
</Grid.ColumnDefinitions>
<Border x:Name="Border" Grid.ColumnSpan="2" Background="Transparent" BorderBrush="Black" BorderThickness="{Binding BorderThickness,RelativeSource={RelativeSource TemplatedParent}}"/>
<Path x:Name="Arrow" Grid.Column="1" Opacity="1" Stroke="Black" StrokeThickness="1.5" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 6 6 L 12 0" />
<Path x:Name="Arrow_checked" Opacity="0" Grid.Column="1" Fill="Black" Stroke="Black" StrokeThickness="1" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 6 6 L 12 0 Z" />
<ContentPresenter TextElement.FontFamily="Segoe Ui Dark" TextElement.FontSize="18" TextElement.Foreground="Black" VerticalAlignment="Center" Grid.Column="0" Margin="10,0,0,0" HorizontalAlignment="Left" RecognizesAccessKey="True" SnapsToDevicePixels="True" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsMouseOver" Value="true">
<Setter TargetName="Border" Property="Background" Value="Gray" />
<Setter TargetName="Border" Property="BorderThickness" Value="1.2" />
</Trigger>
<Trigger Property="IsChecked" Value="False">
<Setter Property="Opacity" Value="1" TargetName="Arrow"/>
<Setter Property="Opacity" Value="0" TargetName="Arrow_checked"/>
</Trigger>
<Trigger Property="ToggleButton.IsChecked" Value="true">
<Setter Property="Opacity" Value="0" TargetName="Arrow"/>
<Setter Property="Opacity" Value="1" TargetName="Arrow_checked"/>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter TargetName="Border" Property="Background" Value="Gray" />
<Setter TargetName="Border" Property="BorderBrush" Value="White" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style TargetType="{x:Type Expander}">
<Setter Property="FontFamily" Value="Segoe Ui Dark"></Setter>
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
<Setter Property="VerticalContentAlignment" Value="Stretch"/>
<Setter Property="MaxHeight" Value="200"></Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Expander}">
<DockPanel>
<ToggleButton x:Name="HeaderSite" Height="35" Background="{TemplateBinding Background}" ContentTemplate="{TemplateBinding HeaderTemplate}" ContentTemplateSelector="{TemplateBinding HeaderTemplateSelector}" Content="{TemplateBinding Header}" DockPanel.Dock="Top" Foreground="Black" FontStyle="{TemplateBinding FontStyle}" FontFamily="Segoe UI Dark"
IsChecked="{Binding IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Template="{StaticResource ComboboxToggleButton}" />
<Border BorderThickness="0,4.5,0,0" BorderBrush="Transparent">
<Border x:Name="bod" BorderBrush="Transparent" SnapsToDevicePixels="True" BorderThickness="1">
<ContentPresenter x:Name="ExpandSite" Focusable="false" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Visibility="Collapsed" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
</Border>
</Border>
</DockPanel>
<ControlTemplate.Triggers>
<Trigger Property="IsExpanded" Value="true">
<Setter Property="Visibility" TargetName="ExpandSite" Value="Visible"/>
<Setter Property="BorderBrush" TargetName="bod" Value="Black"/>
</Trigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground" Value="Gray"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="itemstyle" TargetType="{x:Type ListBoxItem}">
<Setter Property="SnapsToDevicePixels" Value="true" />
<Setter Property="OverridesDefaultStyle" Value="true" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListBoxItem">
<Grid x:Name="Border" Height="40" SnapsToDevicePixels="true">
<Grid.Background>
<SolidColorBrush Color="Transparent" />
</Grid.Background>
<ContentPresenter Name="cmb_name" TextElement.FontFamily="Segoe Ui Dark" TextElement.FontSize="18" TextElement.Foreground="Black" Margin="10,0,0,0" VerticalAlignment="Center"></ContentPresenter>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter TargetName="Border" Property="Background" Value="Gray"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="FocusVisualStyle">
<Setter.Value>
<Style TargetType="Control">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Border BorderBrush="{DynamicResource customBlueBrush}" BorderThickness="1" Margin="1,2,2,2" >
<Rectangle Fill="{DynamicResource customBlueBrush}" Opacity="0.1"></Rectangle>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="CheckBox" >
<Setter Property="SnapsToDevicePixels" Value="True"></Setter>
<Setter Property="OverridesDefaultStyle" Value="True"></Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="CheckBox">
<Grid x:Name="ab" Background="Transparent">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="30"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Rectangle VerticalAlignment="Center" Height="20" Width="20" Fill="White" HorizontalAlignment="Left"></Rectangle>
<Grid x:Name="checkGrid" VerticalAlignment="Center" Height="20" Width="20" Background="Black" HorizontalAlignment="Left">
<Viewbox Height="13" Width="13">
<Path x:Name="Check" SnapsToDevicePixels="True" UseLayoutRounding="True" Width="18.7969" Height="16.3094" Canvas.Left="0" Canvas.Top="1.52588e-005" Stretch="Fill" Fill="White" Data="F1 M 0.731262,8.75935L 0.106262,8.08437C 0.0354614,7.9948 0,7.8979 0,7.79375C 0,7.66875 0.0479736,7.5573 0.143799,7.45937L 1.94067,5.77187C 2.02606,5.69893 2.12708,5.66249 2.24377,5.66249C 2.30212,5.66249 2.36096,5.67397 2.42035,5.69685C 2.47974,5.71977 2.52814,5.75417 2.56567,5.79997L 7.5188,11.1406L 16.0438,0.165604C 16.1417,0.055191 16.2584,1.52588e-005 16.3938,1.52588e-005C 16.4979,1.52588e-005 16.5896,0.0322723 16.6688,0.0968475L 18.6313,1.60939C 18.6709,1.64272 18.7084,1.69011 18.7438,1.75154C 18.7792,1.813 18.7969,1.8698 18.7969,1.92189C 18.7969,2.03435 18.7646,2.1385 18.7,2.23439L 7.74377,16.3094L 0.731262,8.75935 Z " />
</Viewbox>
</Grid>
<Grid Background="Transparent" Grid.Column="1" IsHitTestVisible="True" HorizontalAlignment="Stretch">
<TextBlock VerticalAlignment="Center" FontSize="18" FontFamily="Segoe Ui Dark" Foreground="Black" TextTrimming="CharacterEllipsis">
<ContentPresenter></ContentPresenter>
</TextBlock>
</Grid>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="True">
<Setter Property="Opacity" Value="1" TargetName="Check"></Setter>
</Trigger>
<Trigger Property="IsChecked" Value="False">
<Setter Property="Opacity" Value="0" TargetName="Check"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="FocusVisualStyle">
<Setter.Value>
<Style TargetType="Control">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Border BorderBrush="{DynamicResource customBlueBrush}" SnapsToDevicePixels="True" BorderThickness="1" Margin="-5,1,3,1" />
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<Grid x:Name="gd" >
<Expander Width="500">
<Expander.Header>
<ListBox Background="Transparent" IsHitTestVisible="False" BorderBrush="Transparent" ScrollViewer.HorizontalScrollBarVisibility="Hidden" ScrollViewer.VerticalScrollBarVisibility="Disabled" BorderThickness="0" ItemsSource="{Binding ElementName=lst,Path=SelectedItems}">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Horizontal"></WrapPanel>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ContentData}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander.Header>
<Expander.Content>
<ListBox Background="Transparent" ItemContainerStyle="{StaticResource itemstyle}" HorizontalContentAlignment="Stretch" x:Name="lst" SelectionMode="Multiple">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox x:Name="checkBox" IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBoxItem}}, Path=IsSelected}" Content="{Binding ContentData}"></CheckBox>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander.Content>
</Expander>
</Grid>
c# code
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
ObservableCollection<Customer> custdata = new ObservableCollection<Customer>();
custdata.Add(new Customer() { ContentData = "content1" });
custdata.Add(new Customer() { ContentData = "content2" });
custdata.Add(new Customer() { ContentData = "content3" });
custdata.Add(new Customer() { ContentData = "content4" });
custdata.Add(new Customer() { ContentData = "content5" });
custdata.Add(new Customer() { ContentData = "content6" });
lst.ItemsSource = custdata;
}
}
public class Customer
{
public string ContentData { get; set; }
}
Result

Konrad,
I also decided to use a ComboBox in this manner, because the code was just dead simple. The easiest way I have found to keep the ComboBox popup open is to wire-up to the PreviewMouseDown event of the control in the ComboBox's item template. handle the behavior yourself, and then mark the mouse event handled. Works great for me. In the sample below, each object in FilterItems is a simple view model with a Text property and an IsChecked property.
<ComboBox IsEditable="True" IsReadOnly="False" ItemsSource="{Binding FilterItems}">
<ComboBox.ItemTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding IsChecked}" Content="{Binding Text}"
PreviewMouseDown="FilterComboBox_PreviewMouseDown"/>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
And then my event handler is:
private void FilterComboBox_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
var cb = sender as CheckBox;
if (cb != null)
{
cb.IsChecked = !cb.IsChecked;
e.Handled = true;
}
}

Changing the foreground of button text and image on mouse over

I have a button defined as follows:
<Button x:Name="ContactLink" Canvas.Left="20" Canvas.Top="223" Style="{StaticResource HyperlinkButton}" Click="ContactLink_Clicked">
<WrapPanel>
<Rectangle Width="15" Height="15">
<Rectangle.Fill>
<VisualBrush Stretch="Fill" Visual="{StaticResource appbar_new_window}" />
</Rectangle.Fill>
</Rectangle>
<TextBlock Margin="5 0 0 0" FontWeight="SemiBold" Text="GET IN TOUCH" />
</WrapPanel>
</Button>
As the title says, I would like to define a style which changes the foreground of TextBlock and of the VisualBrush. So far, I have the following style, which doesn't work. It changes the foreground of the textblock and the definition of the BlackBrush resource.
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ControlTemplate x:Key="HyperlinkButtonTemplate" TargetType="{x:Type Button}">
<WrapPanel>
<TextBlock Cursor="Hand">
<ContentPresenter />
</TextBlock>
</WrapPanel>
<ControlTemplate.Triggers>
<Trigger Property="Button.IsMouseOver" Value="True">
<Setter Property="TextBlock.Foreground" Value="#0071bc" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style x:Key="HyperlinkButton" TargetType="{x:Type Button}">
<Setter Property="Template" Value="{StaticResource HyperlinkButtonTemplate}" />
</Style>
</ResourceDictionary>
Any help on getting it to work would be very much appreciated.

You just need to remove the SolidColorBrush you defined inside the trigger
<Trigger Property="Button.IsMouseOver" Value="True">
<Setter Property="TextBlock.Foreground" Value="#0071bc" />
</Trigger>

Probably too late, but I had the same issue and managed to solve it.
Just set name property of the TextBlock then you can refer to that name in the trigger.
<TextBlock Cursor="Hand" Name="MyTextBlock">
<ContentPresenter />
</TextBlock>
<ControlTemplate.Triggers>
<Trigger Property="Button.IsMouseOver" Value="True">
<Setter TargetName="MyTextBlock" Property="Foreground" Value="#0071bc"/>
</Trigger>
</ControlTemplate.Triggers>

How do I access an element inside a style programmatically?

I have a WPF button style below:
<Style x:Key="myButtonStyle" TargetType="{x:Type Button}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Grid Width="{Binding Width}" Height="{Binding Height}">
<Border Name="container" Background="{Binding Background}" CornerRadius="{Binding CornerRadius}">
<TextBlock Margin="10" FontFamily="Arial" FontWeight="Bold" TextAlignment="Left" HorizontalAlignment="Left" VerticalAlignment="Top" Width="Auto" FontSize="{Binding TextSize}" Foreground="White" Text="{Binding Text}" TextWrapping="Wrap"/>
</Border>
<Border Name="overlay" Background="Transparent" CornerRadius="{Binding CornerRadius}" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsPressed" Value="True">
<Setter TargetName="overlay" Property="Opacity" Value="0.6" />
<Setter TargetName="overlay" Property="Background" Value="Black" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
The problem is that, although all of the buttons of my application have the same style, some of them need to have a border around it. Therefore I would like to know if it is possible to access the container border of my style to set its thickness and color? If so how can I do this?
Edit:
I've mixed the suggestions of madd0 and Josh and created a DataTrigger inside my style with a binding to a property that tells me if the button should or should not have a border.
The final code is below:
<Style x:Key="myButtonStyle" TargetType="{x:Type Button}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Grid Width="{Binding Width}" Height="{Binding Height}">
<Border Name="container" Background="{Binding Background}" CornerRadius="{Binding CornerRadius}">
<TextBlock Margin="10" FontFamily="Arial" FontWeight="Bold" TextAlignment="Left" HorizontalAlignment="Left" VerticalAlignment="Top" Width="Auto" FontSize="{Binding TextSize}" Foreground="White" Text="{Binding Text}" TextWrapping="Wrap"/>
</Border>
<Border Name="overlay" Background="Transparent" CornerRadius="{Binding CornerRadius}" />
</Grid>
<ControlTemplate.Triggers>
<DataTrigger Binding="{Binding Path=HasBorder}" Value="true">
<Setter TargetName="container" Property="BorderThickness" Value="{Binding BorderThickness}" />
<Setter TargetName="container" Property="BorderBrush" Value="{Binding BorderBrush}" />
</DataTrigger>
<Trigger Property="IsPressed" Value="True">
<Setter TargetName="overlay" Property="Opacity" Value="0.6" />
<Setter TargetName="overlay" Property="Background" Value="Black" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Thank you all for your help,
Komyg

I think if you extend the Button class and give it a new boolean DependencyProperty, essentially all you need to do is give your Border a name, then in ControlTemplate.Triggers, Trigger off that boolean property to make the border as you need it in your special cases.
It would be similar to what you already have with the IsPressed ControlTemplate trigger.

I don't think you'll really need to access your control template properties. Since Button already has border properties, you ought to just set those properties on the button directly. Then, add the border to your ControlTemplate, binding its properties to that of the button.