Develop Reference

Default ErrorTemplate displays alongside with a custom ErrorTemplate

I have a custom Validation.ErrorTemplate and for some reason, WPF displays both my custom error template and the default one. They both show the same error as expected, however I don't want to display the default ErrorTemplate.
My code:
<Style TargetType="TextBox" x:Key="MyTextBox">
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<Grid>
<Border BorderBrush="red" BorderThickness="1" Background="#11FF0000" IsHitTestVisible="False" x:Name="errorBorder"/>
<AdornedElementPlaceholder x:Name="placeholder" />
<Popup AllowsTransparency="True" HorizontalAlignment="Right" HorizontalOffset="0" VerticalOffset="0" PopupAnimation="Fade" Placement="Right"
PlacementTarget="{Binding ElementName=errorBorder}" IsOpen="{Binding ElementName=placeholder, Path=AdornedElement.IsFocused, Mode=OneWay}">
<StackPanel Orientation="Horizontal">
<Polygon VerticalAlignment="Center" Points="0,4,4,4" Fill="red" Stretch="Fill" Stroke="red"
StrokeThickness="2" />
<Border Background="red" CornerRadius="0" Padding="4">
<TextBlock HorizontalAlignment="Center" Foreground="white" FontWeight="Bold" Margin="2,0,0,0"
Text="{Binding ElementName=placeholder, Path=AdornedElement.ToolTip, Mode=OneWay}" />
</Border>
</StackPanel>
</Popup>
</Grid>
</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>
And this
<Style TargetType="TextBox" BasedOn="{StaticResource MyTextBox}"/>
I'd like to know if anyone knows why WPF displays both my error template and the default one.
EDIT
http://i58.tinypic.com/a14k6q.png - the picture with both errors showing

It is because you defined ErrorTemplate and also defiend a Validation.HasError trigger in your style, you could use one of them. If you want to use the ErrorTemplate you need to remove the trigger, and change the Text binding to "Path=AdornedElement.Validation.Errors).CurrentItem.ErrorContent" then you will just see the result from ErrorTemplate:
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<Grid>
<Border/>
<AdornedElementPlaceholder x:Name="placeholder" />
<Popup>
<StackPanel>
<Polygon/>
<Border>
<TextBlock Text="{Binding ElementName=placeholder,
Path=AdornedElement.(Validation.Errors).CurrentItem.ErrorContent,
Mode=OneWay}" />
</Border>
</StackPanel>
</Popup>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>

WPF Resource section not effecting my Label control in the view

I have created a style for a “required field” label which should place a red asterisk “*” in front of the label. Here is my xaml taken from the Application.Resources section of my WPF application:
<Style TargetType="Label" x:Key="RequiredField">
<Setter Property="Margin" Value="0,0,5,0" />
<Setter Property="HorizontalAlignment" Value="Right" />
<Setter Property="Content">
<Setter.Value>
<ControlTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="*" Foreground="Red" FontSize="10"/>
<TextBlock Text="{Binding}" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
The xaml in my view uses the resource like this:
<Label Grid.Row="1" Grid.Column="0" Style="{StaticResource RequiredField}" Content="Name:"/>
Annoyingly it doesn’t appear to modify the label. Can anyone tell me what I’ve done wrong?

Well your style seems to be wrong. I would try it that way.
<Style TargetType="Label" x:Key="RequiredField">
<Setter Property="Margin" Value="0,0,5,0" />
<Setter Property="HorizontalAlignment" Value="Right" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Label}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="*" Foreground="Red" FontSize="10"/>
<TextBlock Text="{TemplateBinding Content}" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
This should do the trick, but it's totally untested.

The template is assigned to the Content property. That is wrong.
Instead it can be assigned to the Template property but in this case it might be better to use the Validation.ErrorTemplate property because it is meant for validation adorners.
From this article:
<ControlTemplate x:Key="TextBoxErrorTemplate">
<StackPanel>
<StackPanel Orientation="Horizontal">
<Image Height="16" Margin="0,0,5,0"
Source="Assets/warning_48.png"/>
<AdornedElementPlaceholder x:Name="Holder"/>
</StackPanel>
<Label Foreground="Red" Content="{Binding ElementName=Holder,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}"/>
</StackPanel>
</ControlTemplate>
<TextBox x:Name="Box"
Validation.ErrorTemplate="{StaticResource TextBoxErrorTemplate}">

Trigger a WPF setter in code

I'm trying to trigger a setter property in c# code manually, however I'm not sure whether this is possible?
C#;
// apply this setter to the control
myControl.FindResource("StandardTextBoxStyle") as Style;
// how can I trigger ErrorTemplateSetter from here!?
My style;
<Style TargetType="{x:Type TextBox}" x:Key="StandardTextBoxStyle">
<Setter Property="VerticalAlignment" Value="Center" />
<Setter Property="Validation.ErrorTemplate" x:Name="ErrorTemplateSetter">
<Setter.Value>
<ControlTemplate>
<DockPanel LastChildFill="true">
<Border Background="OrangeRed" DockPanel.Dock="right" Margin="5,0,0,0"
Width="20" Height="20" CornerRadius="5"
ToolTip="{Binding ElementName=customAdorner,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">
<TextBlock Text="!" VerticalAlignment="center" HorizontalAlignment="center"
FontWeight="Bold" Foreground="white" />
</Border>
<AdornedElementPlaceholder Name="customAdorner" VerticalAlignment="Center" >
<Border BorderBrush="red" BorderThickness="1" />
</AdornedElementPlaceholder>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

refresh control style based on whether the file exists

I have the following xaml for displaying files. If the file exists on the local machine, it's a clickable hyperlink, otherwise just a normal textblock.
<TextBlock Visibility="{Binding FileName, Converter={StaticResource fileExistsConverter}}" Grid.Column="2" TextDecorations="Underline" Margin="5,0,0,0" Foreground="Black" Text="{Binding FileName}" />
<TextBlock Margin="5,0,0,0" Grid.Column="2" Visibility="{Binding FileName, Converter={StaticResource fileDoesntExistConverter}}">
<Hyperlink Click="Hyperlink_Click_1">
<TextBlock Text="{Binding FileName}" />
</Hyperlink>
</TextBlock>
This works on page load, but doesn't update when the window is open when for example one of the listed files is downloaded. How would I go about triggering a refresh so the XAML can swap the styles?

resources :
<Style x:Key="SwapTemplateStyle" TargetType="ContentControl">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ContentControl">
<TextBlock />
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<DataTrigger Binding="{Binding IsExist}" Value="True">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ContentControl">
<Hyperlink>
<TextBlock />
</Hyperlink>
</ControlTemplate>
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
in your view :
<ContentControl Style="{StaticResource SwapTemplateStyle}" />

Disable blue border for selected Listview item

I have a ListView with Horizontal WrapPanel as its ItemsPanelTemplate.
I want to get rid of the blue background for selected item. It is visible only on the left of the selected item.
There are many similar question on SO and I tried a lot of the solutions and none of them worked.
This is what I have already tried:
<ListView.Resources>
<Style TargetType="{x:Type ListViewItem}">
<Style.Resources>
<!-- Foreground for Selected ListViewItem -->
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}"
Color="Black"/>
<!-- Background for Selected ListViewItem -->
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}"
Color="Transparent"/>
<!--SelectedItem without focus-->
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="Transparent"/>
</Style.Resources>
</Style>
</ListView.Resources>
<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListViewItem}">
<EventSetter Event="Control.MouseDoubleClick" Handler="HandleSelectedItemDoubleClick"/>
<Style.Triggers>
<Trigger Property="IsSelected" Value="true">
<Setter Property="RenderTransform">
<Setter.Value>
<ScaleTransform ScaleX="2" ScaleY="2" CenterX="12" CenterY="12" />
</Setter.Value>
</Setter>
<Setter Property="Panel.ZIndex" Value="150"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="BorderBrush" Value="{x:Null}" />
<Setter Property="Background" Value="{x:Null}" />
</Trigger>
</Style.Triggers>
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Horizontal" Width="210" Margin="15" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>

You need to overwrite the SystemColors.HighlightBrushKey for the ListView to be Transparent (or whatever color you want)
I typically put this in the ListView.Resources so it only applies to the specific ListView, and not all ListViews in my application
<ListView.Resources>
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}"
Color="Transparent"/>
</ListView.Resources>
Its very close to what you have in your code already, but you need to set it for the ListView.Resources, not ListViewItem.Resources

To remove all default styling (hovering, selecting, etc.) just define a custom Template for the ItemContainer (not the Item itself):
<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListViewItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListViewItem}">
<ContentPresenter />
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListView.ItemContainerStyle>
Found on MSDN Forum

This is what did it for me:
<UserControl.Resources>
<DataTemplate x:Key="ItemTemplate">
<StackPanel Orientation="Vertical" Background="Transparent" Opacity="1" Width="185" MaxWidth="185">
<StackPanel Orientation="Horizontal">
<TextBlock
Margin="0,0,10,0"
Background="Transparent"
Foreground="DarkGoldenrod"
FontSize="12" FontStyle="Italic"
Text="{Binding Path=EventTypeName, Mode=OneWay}" />
<TextBlock
Background="Transparent"
Foreground="DarkGoldenrod"
FontSize="12" FontStyle="Italic"
Text="{Binding Path=AccountIdentity, Mode=OneWay}" />
</StackPanel>
<TextBlock
Background="Transparent"
Foreground="DarkGoldenrod" MaxWidth="170"
FontSize="12" FontStyle="Italic" TextTrimming="WordEllipsis" ToolTip="{Binding Path=EventMessage,Mode=OneWay}"
Text="{Binding Path=EventMessage, Mode=OneWay}" />
<TextBlock
Background="Transparent"
Foreground="Black"
FontSize="8"
Text="{Binding Path=EventLoggedOn, Mode=OneWay}"
TextTrimming="WordEllipsis"
ToolTip="{Binding Path=EventLoggedOn, Mode=OneWay}"
Margin="0,0,10,0" />
<StackPanel Orientation="Horizontal">
<TextBlock
Background="Transparent"
Foreground="Black"
FontSize="8"
Text="{Binding Path=QualifiedCreator, Mode=OneWay}" />
</StackPanel>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="SelectedTemplate">
<StackPanel Orientation="Vertical" Background="LightGray" Opacity="1" Width="185" MaxWidth="185">
<StackPanel Orientation="Horizontal">
<TextBlock
Margin="0,0,10,0"
Background="Transparent"
Foreground="Yellow"
FontSize="12" FontStyle="Italic"
Text="{Binding Path=EventTypeName, Mode=OneWay}" />
<TextBlock
Background="Transparent"
Foreground="Yellow"
FontSize="12" FontStyle="Italic"
Text="{Binding Path=AccountIdentity, Mode=OneWay}" />
</StackPanel>
<TextBlock
Background="Transparent"
Foreground="DarkGoldenrod" MaxWidth="170"
FontSize="12" FontStyle="Italic" TextTrimming="WordEllipsis" ToolTip="{Binding Path=EventMessage,Mode=OneWay}"
Text="{Binding Path=EventMessage, Mode=OneWay}" />
<TextBlock
Background="Transparent"
Foreground="Black"
FontSize="8"
Text="{Binding Path=EventLoggedOn, Mode=OneWay}"
TextTrimming="WordEllipsis"
ToolTip="{Binding Path=EventLoggedOn, Mode=OneWay}"
Margin="0,0,10,0" />
<StackPanel Orientation="Horizontal">
<TextBlock
Background="Transparent"
Foreground="Black"
FontSize="8"
Text="{Binding Path=QualifiedCreator, Mode=OneWay}" />
</StackPanel>
</StackPanel>
</DataTemplate>
<Style TargetType="ListViewItem" x:Key="ContainerStyle">
<Setter Property="Background" Value="Transparent"/>
<Setter Property="ContentTemplate" Value="{StaticResource ResourceKey=ItemTemplate}" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True" >
<Setter Property="ContentTemplate" Value="{StaticResource ResourceKey=SelectedTemplate}" />
</Trigger>
</Style.Triggers>
</Style>
</UserControl.Resources>

The simplest way to do this is to set the background to {x:Null} when the item is selected, using a trigger.
<ListView>
<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListViewItem}">
<Style.Triggers>
<Trigger Property="IsSelected"
Value="True">
<Setter Property="Background"
Value="{x:Null}" />
<Setter Property="BorderBrush"
Value="{x:Null}" />
</Trigger>
</Style.Triggers>
</Style>
</ListView.ItemContainerStyle>
...
</ListView>