WPF IsReadOnly property problem

Infographics by vecteezy.com

Hmm... I don't know how many peoples have met with similar problem to my, but I think this what I found is really strange. The problem is with binding something to IsReadOnly property, for example in TextBox control. I created some template which is using this property as a trigger source, so when control is ReadOnly its look is different.

When I was trying to create trigger in Expression Blend 4, the property disappears like on picture below.



Great! Don't You think :p
I want to show here some solution for this problem. Here is my template:

	<Style x:Key="ReadOnlyTextBox" TargetType="{x:Type TextBox}">
	<Setter Property="Template">
	<Setter.Value>
	<ControlTemplate TargetType="{x:Type TextBox}">
	<Border x:Name="border"
	BorderThickness="{TemplateBinding BorderThickness}"
	CornerRadius="3"
	Padding="1"
	BorderBrush="Black">
	<Border.Background>
	<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
	<GradientStop Color="#FFD2D0D0" Offset="0"/>
	<GradientStop Color="White" Offset="0.385"/>
	</LinearGradientBrush>
	</Border.Background>
	<VisualStateManager.VisualStateGroups>
	<VisualStateGroup x:Name="CommonStates">
	<VisualState x:Name="Normal"/>
	<VisualState x:Name="Disabled"/>
	<VisualState x:Name="MouseOver"/>
	<VisualState x:Name="ReadOnly"/>
	</VisualStateGroup>
	</VisualStateManager.VisualStateGroups>
	<Grid Height="Auto">
	<Microsoft_Windows_Themes:ListBoxChrome x:Name="Bd"
	RenderMouseOver="{TemplateBinding IsMouseOver}"
	RenderFocused="{TemplateBinding IsKeyboardFocusWithin}"
	SnapsToDevicePixels="True"
	BorderThickness="0"
	d:LayoutOverrides="Width, Height">
	<ScrollViewer x:Name="PART_ContentHost"
	SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
	Foreground="Black"/>
	</Microsoft_Windows_Themes:ListBoxChrome>
	<TextBlock x:Name="textBlock"
	HorizontalAlignment="Stretch"
	TextWrapping="Wrap"
	Text="{TemplateBinding Text}"
	Margin="3,1,3,0"
	VerticalAlignment="Top"
	Visibility="Collapsed"
	Foreground="White"/>
	</Grid>
	</Border>
	<ControlTemplate.Triggers>
	<Trigger Property="IsEnabled" Value="False">
	<Setter Property="Background"
	TargetName="Bd"
	Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
	<Setter Property="Foreground"
	Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
	</Trigger>
	<Trigger Property="core:Attach.IsReadOnly" Value="True">
	<Setter Property="Visibility" TargetName="textBlock" Value="Visible"/>
	<Setter Property="Visibility" TargetName="Bd" Value="Collapsed"/>
	<Setter Property="Background" TargetName="border">
	<Setter.Value>
	<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
	<GradientStop Color="#19FFFFFF" Offset="0"/>
	<GradientStop Color="#19FFFFFF" Offset="0.385"/>
	</LinearGradientBrush>
	</Setter.Value>
	</Setter>
	<Setter Property="BorderBrush" TargetName="border" Value="#7FFFFFFF"/>
	</Trigger>
	</ControlTemplate.Triggers>
	</ControlTemplate>
	</Setter.Value>
	</Setter>
	</Style>

view raw ReadOnlyTextBoxStyle.xaml hosted with ❤ by GitHub

But it is not the point. Look on line 59 on previous listing - one important line. There I defined trigger invoked when my attached property will change: core:Attach.IsReadOnly. So now I can use this like below in XAML code.

<TextBox x:Name="MyTextBox" core:Attach.IsReadOnly="{Binding ReadMode}" />

view raw TextBoxIsReadonly_AttachedProperty.xaml hosted with ❤ by GitHub

I'm using here Binding to ReadMode property from DataContext. Below definition of this attached property.

	/// <summary>
	/// Attached properties class.
	/// </summary>
	public class Attach
	{
	#region IsReadOnlyProperty
	/// <summary>
	/// <para>Returns value of attached IsReadOnlyProperty.</para>
	/// </summary>
	public static bool GetIsReadOnly(DependencyObject obj)
	{
	return (bool)obj.GetValue(IsReadOnlyProperty);
	}
	/// <summary>
	/// <para>Sets value for attached IsReadOnlyProperty.</para>
	/// </summary>
	public static void SetIsReadOnly(DependencyObject obj, bool value)
	{
	obj.SetValue(IsReadOnlyProperty, value);
	}
	/// <summary>
	/// <para>Attached property:</para>
	/// <para>Allow to set IsReadOnly property for problematic controls.</para>
	/// </summary>
	public static readonly DependencyProperty IsReadOnlyProperty =
	DependencyProperty.RegisterAttached("IsReadOnly", typeof(bool), typeof(Attach), new UIPropertyMetadata(false));
	#endregion
	}

view raw Attach_IsReadOnlyProperty.cs hosted with ❤ by GitHub

I hope this will help someone.

Oh, and one think, I created this on Windows 7, so in Template I'm using PresentationFramework.Aero reference, if You are using other version You must create the template by Yourself and then add my Trigger definition in XAML.

I'm pretty sure you see that this is just simple example of using Attached properties :-)