Develop Reference

How to disable button but force children to be enabled?

I am trying to figure out how I can set the "IsEnabled" property to false on a Button but then have the children (in my case a Combobox) be enabled. It seems the children inherit the property value from the parent element (in this case the disabled button) and therefore also disables itself. How can I prevent this?
I have tried to lookup answers but they all use "Override Metadata" which WinUI3 and Windows App SDK do not contain.
<Button
x:Name="Button1"
IsEnabled="False">
<Button.Content>
<ComboBox x:Name="ComboBox1" />
</Button.Content>
</Button>

You can create a custom control like this:
Generic.xaml
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Buttons">
<Style TargetType="local:CustomButton">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="local:CustomButton">
<Grid
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<Button
x:Name="ButtonControl"
HorizontalAlignment="Center"
VerticalAlignment="Center"
IsEnabled="{TemplateBinding IsButtonEnabled}" />
<ContentControl
x:Name="ContentControl"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Content="{TemplateBinding Content}"
IsEnabled="{TemplateBinding IsContentEnabled}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
CustomButton.cs
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
namespace Buttons;
[TemplatePart(Name = nameof(ButtonControl), Type = typeof(Button))]
[TemplatePart(Name = nameof(ContentControl), Type = typeof(ContentControl))]
public sealed class CustomButton : ContentControl
{
public static readonly DependencyProperty IsButtonEnabledProperty = DependencyProperty.Register(
nameof(IsButtonEnabled),
typeof(bool),
typeof(CustomButton),
new PropertyMetadata(true));
public static readonly DependencyProperty IsContentEnabledProperty = DependencyProperty.Register(
nameof(IsContentEnabled),
typeof(bool),
typeof(CustomButton),
new PropertyMetadata(true));
public CustomButton()
{
this.DefaultStyleKey = typeof(CustomButton);
}
public bool IsButtonEnabled
{
get => (bool)GetValue(IsButtonEnabledProperty);
set => SetValue(IsButtonEnabledProperty, value);
}
public bool IsContentEnabled
{
get => (bool)GetValue(IsContentEnabledProperty);
set => SetValue(IsContentEnabledProperty, value);
}
private Button? ButtonControl { get; set; }
private ContentControl? ContentControl { get; set; }
protected override void OnApplyTemplate()
{
base.OnApplyTemplate();
ButtonControl = GetTemplateChild(nameof(ButtonControl)) as Button;
if (GetTemplateChild(nameof(ContentControl)) is ContentControl contentControl)
{
if (ContentControl is not null)
{
ContentControl.SizeChanged -= ContentControl_SizeChanged;
}
ContentControl = contentControl;
ContentControl.SizeChanged += ContentControl_SizeChanged;
}
}
private void ContentControl_SizeChanged(object sender, SizeChangedEventArgs e)
{
if (sender is ContentControl contentControl &&
ButtonControl is not null)
{
ButtonControl.Width = contentControl.ActualWidth + 20.0;
ButtonControl.Height = contentControl.ActualHeight + 20.0;
}
}
}
And use it like this:
MainWindow.xaml
<Grid>
<local:CustomButton
IsButtonEnabled="False"
IsContentEnabled="True">
<ComboBox
SelectedIndex="0"
SelectionChanged="ComboBox_SelectionChanged">
<x:String>Blue</x:String>
<x:String>Green</x:String>
<x:String>Red</x:String>
</ComboBox>
</local:CustomButton>
</Grid>

AutomationProperties.AutomationId on custom control not exposed

I've been banging my head against this problem for 3 days and haven't been able to find an answer.
I've got an application written in WPF (dot Net 4.5) and I'm working with Teststack.White trying to write some automated GUI test cases. The developers have given x:Names to some of the controls and they show up through Inspect/WPF Inspector/Visual UI Automation Verify as the AutomationId just fine.
There are other controls that are buried a bit deeper that I've been tasked with giving automation ids to (mostly as an exercise so I can get more familiar with the back-end). This is where I've been banging my head against things.
I've tried giving the controls the AutomationProperties.AutomationId (and .Name) attribute. I've given AutomationProperties a name space definition. As well I've made sure SWA.Peers is referenced.
I haven't tried using property setters in XAML as they don't make much sense currently and I'm hoping don't need to write stuff in C# to set them (if I do, I'll do it but just hoping).
One of my co-workers sat down and we pulled out the bare minimum setup that isn't exposing the Automation ID property (unfortunately he as well as the other devs are drawing a blank as to why this isn't happening). It looks like:
MainWindow.xaml:
<Window x:Class="TestAutomationUI.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:autoProp="clr-namespace:System.Windows.Automation;assembly=PresentationCore"
xmlns:common="clr-namespace:Asi.Ui.Common"
Title="Test UI (Pick me)" Height="455.075" Width="525">
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/IconLabelButton.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
<StackPanel x:Name="PresentationRoot">
<common:IconLabelButton x:Name="TestButton" autoProp:AutomationProperties.AutomationId="TestButtonClick" Text="Stuff" Margin="245,0,214.4,0" RenderTransformOrigin="4.648,0.588" Height="32">
</common:IconLabelButton>
</StackPanel>
</Window>
IconLabelButton.xaml:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:autoProp="clr-namespace:System.Windows.Automation;assembly=PresentationCore"
xmlns:common="clr-namespace:Asi.Ui.Common">
<Style TargetType="common:IconLabelButton">
<Setter Property="Template" Value="{DynamicResource Asi.Ui.Common.IconLabelButton}" />
<Setter Property="IsTabStop" Value="False" />
<Setter Property="Background" Value="Transparent" />
<Setter Property="FontWeight" Value="{DynamicResource Mobius.UI.Resources.Fonts.WeightLight}"/>
<Setter Property="Spacing" Value="10" />
</Style>
<ControlTemplate x:Key="Asi.Ui.Common.IconLabelButton" TargetType="common:IconLabelButton">
<Border Background="{TemplateBinding Background}" Height="30">
<Button Style="{DynamicResource Mobius.UI.Resources.Styles.IconButton}" Margin="0" Padding="0" HorizontalContentAlignment="Stretch" HorizontalAlignment="Left"
Command="{TemplateBinding Command}" CommandParameter="{TemplateBinding CommandParameter}" Foreground="{TemplateBinding Foreground}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="22" />
<ColumnDefinition Width="{TemplateBinding Spacing}" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid Grid.Column="0" HorizontalAlignment="Left" VerticalAlignment="Top" Width="22" Height="22">
<Path Margin="1" Height="20" Width="20" Fill="{Binding Foreground, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ContentControl}}}" Data="{TemplateBinding Icon}" Stretch="Fill"/>
<Path Margin="1" Height="20" Width="20" Fill="{TemplateBinding AdornerIconFill}" Data="{TemplateBinding AdornerIcon}" Stretch="Fill"/>
</Grid>
<TextBlock Grid.Column="2" Text="{TemplateBinding Text}" VerticalAlignment="Center" Foreground="{Binding Foreground, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ContentControl}}}" FontFamily="{TemplateBinding FontFamily}" FontSize="{TemplateBinding FontSize}" FontStretch="{TemplateBinding FontStretch}" FontWeight="{TemplateBinding FontWeight}"/>
</Grid>
</Button>
</Border>
</ControlTemplate>
</ResourceDictionary>
IconLabelButton.xaml.cs:
using System;
using System.Windows;
using System.Windows.Automation;
using System.Windows.Automation.Peers;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
namespace Asi.Ui.Common
{
public class IconLabelButton : Control
{
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(IconLabelButton), new PropertyMetadata(default(string)));
public static readonly DependencyProperty AdornerIconProperty =
DependencyProperty.Register("AdornerIcon", typeof(object), typeof(IconLabelButton), new PropertyMetadata(default(object)));
public static readonly DependencyProperty IconProperty =
DependencyProperty.Register("Icon", typeof(object), typeof(IconLabelButton), new PropertyMetadata(default(object)));
public static readonly DependencyProperty CommandProperty =
DependencyProperty.Register("Command", typeof(ICommand), typeof(IconLabelButton), new PropertyMetadata(default(ICommand)));
public static readonly DependencyProperty CommandParameterProperty =
DependencyProperty.Register("CommandParameter", typeof(object), typeof(IconLabelButton), new PropertyMetadata(default(ICommand)));
public static readonly DependencyProperty SpacingProperty =
DependencyProperty.Register("Spacing", typeof(GridLength), typeof(IconLabelButton), new PropertyMetadata(default(GridLength)));
public static readonly DependencyProperty IconButtonSizeProperty =
DependencyProperty.Register("IconButtonSize", typeof(GridLength), typeof(IconLabelButton), new PropertyMetadata(default(GridLength)));
public static readonly DependencyProperty AdornerIconFillProperty =
DependencyProperty.Register("AdornerIconFill", typeof(Brush), typeof(IconLabelButton), new PropertyMetadata(default(Brush)));
static IconLabelButton()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(IconLabelButton), new FrameworkPropertyMetadata(typeof(IconLabelButton)));
}
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public object AdornerIcon
{
get { return GetValue(AdornerIconProperty); }
set { SetValue(AdornerIconProperty, value); }
}
public object Icon
{
get { return GetValue(IconProperty); }
set { SetValue(IconProperty, value); }
}
public ICommand Command
{
get { return (ICommand)GetValue(CommandProperty); }
set { SetValue(CommandProperty, value); }
}
public object CommandParameter
{
get { return GetValue(CommandParameterProperty); }
set { SetValue(CommandParameterProperty, value); }
}
public GridLength Spacing
{
get { return (GridLength)GetValue(SpacingProperty); }
set { SetValue(SpacingProperty, value); }
}
public GridLength IconButtonSize
{
get { return (GridLength)GetValue(IconButtonSizeProperty); }
set { SetValue(IconButtonSizeProperty, value); }
}
public Brush AdornerIconFill
{
get { return (Brush)GetValue(AdornerIconFillProperty); }
set { SetValue(AdornerIconFillProperty, value); }
}
}
}
I apologize if this is an easy question (or if I'm not asking the right one). I'm an entry-level programmer who only has a cursory familiarity with WPF/XAML.
Thanks in advance for the help! (Hopefully it's any easy fix!)
Update: After doing some further digging on UI Automation Providers, it looks like all custom controls have to be written to support AutomationProperties. Of course talking with the devs that isn't case.
I'll post more information when I get the solution figured out.

There is no AutomationPeer for your control. So your AutomationId setup does not set anything.
Override OnCreateAutomationPeer in your control codebehind like this:
protected override AutomationPeer OnCreateAutomationPeer()
{
return new IconLabelButtonAutomationPeer(this);
}
where your new IconLabelButtonAutomationPeer looks like this:
public class IconLabelButtonAutomationPeer : FrameworkElementAutomationPeer
{
public IconLabelButtonAutomationPeer(IconLabelButton owner)
: base(owner)
{
}
}

Binding Validation.HasError property in MVVM

I am currently implementing a ValidationRule to check if some invalid character are in a TextBox. I am happy that setting the class I have implemented that inherits ValidationRule on my TextBox sets it in red when such characters are found, but I would also like to use the Validation.HasError property or the Validation.Errors property to pop a messagebox telling the user that there are errors in the various textboxes in the page.
Is there a way to bind a property in my ViewModel to the Validation.HasError and/or to the Validation.Errors properties in order for me to have access to them in my ViewModel?
Here is my error style for the TextBox:
<Style x:Key="ErrorValidationTextBox" TargetType="{x:Type pres:OneTextBox}">
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<DockPanel LastChildFill="True">
<TextBlock DockPanel.Dock="Right"
Foreground="Red"
FontSize="12pt"
Text="{Binding ElementName=MyAdorner,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">
</TextBlock>
<AdornedElementPlaceholder x:Name="MyAdorner"/>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Here is how I declare my TextBox (OneTextBox encapsulates the regular WPF TextBox) in my XAML:
<pres:OneTextBox Watermark="Name..." Margin="85,12,0,0" Style="{StaticResource ErrorValidationTextBox}"
AcceptsReturn="False" MaxLines="1" Height="22" VerticalAlignment="Top"
HorizontalAlignment="Left" Width="300" >
<pres:OneTextBox.Text>
<Binding Path="InterfaceSpecification.Name" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<interfaceSpecsModule:NoInvalidCharsRule/>
</Binding.ValidationRules>
</Binding>
</pres:OneTextBox.Text>
</pres:OneTextBox>

The Validation.HasError is readonly property, therefore Binding will not work with this property. This can be seen in ILSpy:
public virtual bool HasError
{
get
{
return this._validationError != null;
}
}
As an alternative, you should see a great article which provides a solution in the form of use attached dependency properties, there you will see a detailed explanation of the example.
Below is a full example from this article, I just translated it under C#, the original language is VB.NET:
XAML
<Window x:Class="HasErrorTestValidation.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:HasErrorTestValidation"
WindowStartupLocation="CenterScreen"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:TestData />
</Window.DataContext>
<StackPanel>
<TextBox x:Name="TestTextBox"
local:ProtocolSettingsLayout.MVVMHasError="{Binding Path=HasError}">
<TextBox.Text>
<Binding Path="TestText" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<local:OnlyNumbersValidationRule ValidatesOnTargetUpdated="True"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
<TextBlock>
<TextBlock.Text>
<Binding Path="HasError" StringFormat="HasError is {0}"/>
</TextBlock.Text>
</TextBlock>
<TextBlock>
<TextBlock.Text>
<Binding Path="(Validation.HasError)" ElementName="TestTextBox" StringFormat="Validation.HasError is {0}"/>
</TextBlock.Text>
</TextBlock>
</StackPanel>
</Window>
Code-behind
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
}
#region Model
public class TestData : INotifyPropertyChanged
{
private bool _hasError = false;
public bool HasError
{
get
{
return _hasError;
}
set
{
_hasError = value;
NotifyPropertyChanged("HasError");
}
}
private string _testText = "0";
public string TestText
{
get
{
return _testText;
}
set
{
_testText = value;
NotifyPropertyChanged("TestText");
}
}
#region PropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(string sProp)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(sProp));
}
}
#endregion
}
#endregion
#region ValidationRule
public class OnlyNumbersValidationRule : ValidationRule
{
public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
var result = new ValidationResult(true, null);
string NumberPattern = #"^[0-9-]+$";
Regex rgx = new Regex(NumberPattern);
if (rgx.IsMatch(value.ToString()) == false)
{
result = new ValidationResult(false, "Must be only numbers");
}
return result;
}
}
#endregion
public class ProtocolSettingsLayout
{
public static readonly DependencyProperty MVVMHasErrorProperty= DependencyProperty.RegisterAttached("MVVMHasError",
typeof(bool),
typeof(ProtocolSettingsLayout),
new FrameworkPropertyMetadata(false,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
null,
CoerceMVVMHasError));
public static bool GetMVVMHasError(DependencyObject d)
{
return (bool)d.GetValue(MVVMHasErrorProperty);
}
public static void SetMVVMHasError(DependencyObject d, bool value)
{
d.SetValue(MVVMHasErrorProperty, value);
}
private static object CoerceMVVMHasError(DependencyObject d,Object baseValue)
{
bool ret = (bool)baseValue;
if (BindingOperations.IsDataBound(d,MVVMHasErrorProperty))
{
if (GetHasErrorDescriptor(d)==null)
{
DependencyPropertyDescriptor desc = DependencyPropertyDescriptor.FromProperty(Validation.HasErrorProperty, d.GetType());
desc.AddValueChanged(d,OnHasErrorChanged);
SetHasErrorDescriptor(d, desc);
ret = System.Windows.Controls.Validation.GetHasError(d);
}
}
else
{
if (GetHasErrorDescriptor(d)!=null)
{
DependencyPropertyDescriptor desc= GetHasErrorDescriptor(d);
desc.RemoveValueChanged(d, OnHasErrorChanged);
SetHasErrorDescriptor(d, null);
}
}
return ret;
}
private static readonly DependencyProperty HasErrorDescriptorProperty = DependencyProperty.RegisterAttached("HasErrorDescriptor",
typeof(DependencyPropertyDescriptor),
typeof(ProtocolSettingsLayout));
private static DependencyPropertyDescriptor GetHasErrorDescriptor(DependencyObject d)
{
var ret = d.GetValue(HasErrorDescriptorProperty);
return ret as DependencyPropertyDescriptor;
}
private static void OnHasErrorChanged(object sender, EventArgs e)
{
DependencyObject d = sender as DependencyObject;
if (d != null)
{
d.SetValue(MVVMHasErrorProperty, d.GetValue(Validation.HasErrorProperty));
}
}
private static void SetHasErrorDescriptor(DependencyObject d, DependencyPropertyDescriptor value)
{
var ret = d.GetValue(HasErrorDescriptorProperty);
d.SetValue(HasErrorDescriptorProperty, value);
}
}
As an alternative to the use of ValidationRule, in MVVM style you can try to implement IDataErrorInfo Interface. For more info see this:
Enforcing Complex Business Data Rules with WPF

all perfect work set NotifyOnValidationError="True" on binding;
(or maybe with binding group also possible)
then use
<Button IsEnabled="{Binding ElementName=tbPeriod, Path=(Validation.HasError)}"
sample with one textBox:
<val:RangeRulecan be changed to ms sample agerangerule etc
<TextBox MaxLength="5" x:Name="tbPeriod" HorizontalAlignment="Left" VerticalAlignment="Top" Width="162" Margin="10,10,0,0" Style="{StaticResource TextBoxInError}">
<TextBox.Text>
<Binding Path="ReportPeriod" UpdateSourceTrigger="PropertyChanged" NotifyOnValidationError="True">
<Binding.ValidationRules>
<val:RangeRule Min="70" Max="5000" />
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>

In response to Anatoliy's request for an example of a non-working project:
Generic.xaml
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TestAttachedPropertyValidationError">
<Style TargetType="{x:Type local:TextBoxCustomControl}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:TextBoxCustomControl}">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="10"/>
<ColumnDefinition Width="50"/>
</Grid.ColumnDefinitions>
<Grid.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</Grid.Resources>
<Label
Grid.Row ="0"
Grid.Column="0"
Content="Enter a numeric value:" />
<TextBox
Grid.Row ="0"
Grid.Column="2"
local:HasErrorUtility.HasError="{Binding NumericPropHasError, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"
Text="{Binding NumericProp, Mode=TwoWay, UpdateSourceTrigger=LostFocus, RelativeSource={RelativeSource TemplatedParent}}" />
<Label
Grid.Row ="1"
Grid.Column="0"
Content="Value entered:" />
<Label
Grid.Row ="1"
Grid.Column="2"
Content="{TemplateBinding NumericProp}" />
<Label
Grid.Row ="2"
Grid.Column="0"
Grid.ColumnSpan="3"
Visibility="{TemplateBinding NumericPropHasError, Converter={StaticResource BooleanToVisibilityConverter}}"
Foreground="Red"
Content="Not a numeric value" />
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
TextBoxCustomControl.cs
using System.Windows;
using System.Windows.Controls;
namespace TestAttachedPropertyValidationError
{
public class TextBoxCustomControl : Control
{
static TextBoxCustomControl()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(TextBoxCustomControl), new FrameworkPropertyMetadata(typeof(TextBoxCustomControl)));
}
public static readonly DependencyProperty NumericPropProperty =
DependencyProperty.Register("NumericProp", typeof (int), typeof (TextBoxCustomControl), new PropertyMetadata(default(int)));
public int NumericProp
{
get { return (int) GetValue(NumericPropProperty); }
set { SetValue(NumericPropProperty, value); }
}
public static readonly DependencyProperty NumericPropHasErrorProperty =
DependencyProperty.Register("NumericPropHasError", typeof (bool), typeof (TextBoxCustomControl), new PropertyMetadata(default(bool)));
public bool NumericPropHasError
{
get { return (bool) GetValue(NumericPropHasErrorProperty); }
set { SetValue(NumericPropHasErrorProperty, value); }
}
}
}
HasErrorUtility.cs
using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
namespace TestAttachedPropertyValidationError
{
class HasErrorUtility
{
public static readonly DependencyProperty HasErrorProperty = DependencyProperty.RegisterAttached("HasError",
typeof(bool),
typeof(HasErrorUtility),
new FrameworkPropertyMetadata(false,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
null,
CoerceHasError));
public static bool GetHasError(DependencyObject d)
{
return (bool)d.GetValue(HasErrorProperty);
}
public static void SetHasError(DependencyObject d, bool value)
{
d.SetValue(HasErrorProperty, value);
}
private static object CoerceHasError(DependencyObject d, Object baseValue)
{
var ret = (bool)baseValue;
if (BindingOperations.IsDataBound(d, HasErrorProperty))
{
if (GetHasErrorDescriptor(d) == null)
{
var desc = DependencyPropertyDescriptor.FromProperty(Validation.HasErrorProperty, d.GetType());
desc.AddValueChanged(d, OnHasErrorChanged);
SetHasErrorDescriptor(d, desc);
ret = Validation.GetHasError(d);
}
}
else
{
if (GetHasErrorDescriptor(d) != null)
{
var desc = GetHasErrorDescriptor(d);
desc.RemoveValueChanged(d, OnHasErrorChanged);
SetHasErrorDescriptor(d, null);
}
}
return ret;
}
private static readonly DependencyProperty HasErrorDescriptorProperty = DependencyProperty.RegisterAttached("HasErrorDescriptor",
typeof(DependencyPropertyDescriptor),
typeof(HasErrorUtility));
private static DependencyPropertyDescriptor GetHasErrorDescriptor(DependencyObject d)
{
var ret = d.GetValue(HasErrorDescriptorProperty);
return ret as DependencyPropertyDescriptor;
}
private static void SetHasErrorDescriptor(DependencyObject d, DependencyPropertyDescriptor value)
{
d.SetValue(HasErrorDescriptorProperty, value);
}
private static void OnHasErrorChanged(object sender, EventArgs e)
{
var d = sender as DependencyObject;
if (d != null)
{
d.SetValue(HasErrorProperty, d.GetValue(Validation.HasErrorProperty));
}
}
}
}
ViewModel.cs
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace TestAttachedPropertyValidationError
{
public class ViewModel :INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private int _vmNumericProp;
private bool _vmNumericPropHasError;
public int VmNumericProp
{
get { return _vmNumericProp; }
set
{
_vmNumericProp = value;
OnPropertyChanged();
}
}
public bool VmNumericPropHasError
{
get { return _vmNumericPropHasError; }
set
{
_vmNumericPropHasError = value;
OnPropertyChanged();
}
}
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
MainWindow.xaml
<Window x:Class="TestAttachedPropertyValidationError.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TestAttachedPropertyValidationError"
Title="MainWindow" Height="350" Width="525">
<StackPanel Margin="10">
<StackPanel.Resources>
<local:ViewModel x:Key="VM1"/>
<local:ViewModel x:Key="VM2"/>
</StackPanel.Resources>
<Label Content="Custom Control...}"></Label>
<local:TextBoxCustomControl
Margin="10"
DataContext="{StaticResource VM1}"
NumericProp="{Binding VmNumericProp}"
NumericPropHasError="{Binding VmNumericPropHasError}"/>
<Label Content="Regular XAML...}" Margin="0,20,0,0"/>
<Grid
Margin="10"
DataContext="{StaticResource VM2}"
>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="10"/>
<ColumnDefinition Width="50"/>
</Grid.ColumnDefinitions>
<Grid.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</Grid.Resources>
<Label
Grid.Row ="0"
Grid.Column="0"
Content="Enter a numeric value:" />
<TextBox
Grid.Row ="0"
Grid.Column="2"
local:HasErrorUtility.HasError="{Binding VmNumericPropHasError, Mode=TwoWay}"
Text="{Binding VmNumericProp, Mode=TwoWay, UpdateSourceTrigger=LostFocus}" />
<Label
Grid.Row ="1"
Grid.Column="0"
Content="Value entered:" />
<Label
Grid.Row ="1"
Grid.Column="2"
Content="{Binding VmNumericProp}" />
<Label
Grid.Row ="2"
Grid.Column="0"
Grid.ColumnSpan="3"
Visibility="{Binding VmNumericPropHasError, Converter={StaticResource BooleanToVisibilityConverter}}"
Foreground="Red"
Content="Not a numeric value" />
</Grid>
</StackPanel>

Can't create dependency property in a UserControl in a Windows Runtime Component library

I wanted to created data bindable property inside a user control. And this user control contains inside a "Windows Runtime Component" project. I used below code to create property.
public MyItem CurrentItem
{
get { return (MyItem)GetValue(CurrentItemProperty); }
set { SetValue(CurrentItemProperty, value); }
}
// Using a DependencyProperty as the backing store for CurrentItem.
// This enables animation, styling, binding, etc...
public static readonly DependencyProperty CurrentItemProperty =
DependencyProperty.Register("CurrentItem", typeof(MyItem), typeof(CollapseUserControl), new PropertyMetadata(null));
When I compile the project I get below error.
Type 'HierachyLib.CollapseUserControl' contains externally visible field 'HierachyLib.CollapseUserControl.CurrentItemProperty'. Fields can be exposed only by structures.
Update 1 - Source code for whole class
public sealed partial class CollapseUserControl : UserControl, IHierarchyHeightFix
{
public MyItem CurrentItem
{
get { return (MyItem)GetValue(CurrentItemProperty); }
set { SetValue(CurrentItemProperty, value); }
}
// Using a DependencyProperty as the backing store for CurrentItem. This enables animation, styling, binding, etc...
public static readonly DependencyProperty CurrentItemProperty =
DependencyProperty.Register("CurrentItem", typeof(MyItem), typeof(CollapseUserControl), new PropertyMetadata(null));
Boolean viewState = true;
public CollapseUserControl()
{
this.DataContext = CurrentItem;
this.InitializeComponent();
this.Loaded += CollapseUserControl_Loaded;
}
void CollapseUserControl_Loaded(object sender, RoutedEventArgs e)
{
LoadData();
if (this.Height.Equals(double.NaN))
{
this.Height = 50;
}
//this.Height = 50;
//this.Width = double.NaN;
}
private void LoadData()
{
if (CurrentItem != null)
{
if (CurrentItem.IsValueControl)
{
ChildItemContainer.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
ValueItem.Visibility = Windows.UI.Xaml.Visibility.Visible;
ValueItem.Text = CurrentItem.Value;
}
else
{
ChildItemContainer.Visibility = Windows.UI.Xaml.Visibility.Visible;
ValueItem.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
ChildItems.ItemsSource = CurrentItem.Childs;
//foreach (MyItem item in CurrentItem.Childs)
//{
// CollapseUserControl control = new CollapseUserControl();
// control.CurrentItem = item;
// ChildItems.Items.Add(control);
//}
ChildItems.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
}
}
}
private void Button_Click_1(object sender, RoutedEventArgs e)
{
if (viewState)
{
ChildItems.Visibility = Windows.UI.Xaml.Visibility.Visible;
//show.Begin();
}
else
{
//hide.Begin();
ChildItems.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
}
viewState = !viewState;
}
private void hide_Completed_1(object sender, object e)
{
ChildItems.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
}
private void show_Completed_1(object sender, object e)
{
}
}
Update 2 : XAML Code
<UserControl
x:Class="HierachyLib.CollapseUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:HierachyLib"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<UserControl.Resources>
<DataTemplate x:Key="ReviewsItemsTemplate">
<StackPanel Margin="0,0,0,20">
<TextBlock Text="TEST" />
<TextBlock Text="TEST"/>
</StackPanel>
</DataTemplate>
<ItemsPanelTemplate x:Key="ReviewsItemsPanelTemplate">
<StackPanel Margin="0,0,0,0" Width="Auto"/>
</ItemsPanelTemplate>
</UserControl.Resources>
<!--xmlns:my="clr-namespace:HierarchyCollapse"-->
<Grid>
<Grid Name="ChildItemContainer">
<Grid.RowDefinitions>
<RowDefinition Height="40" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Rectangle Grid.Row="0" Margin="0,0,70,0" Fill="Transparent" Canvas.ZIndex="4"/>
<ListView HorizontalContentAlignment="Stretch" Background="#FF6599CD" CanDragItems="False" CanReorderItems="False" Grid.Row="0"
ScrollViewer.VerticalScrollBarVisibility="Hidden" ScrollViewer.VerticalScrollMode="Disabled"
ScrollViewer.HorizontalScrollBarVisibility="Hidden" ScrollViewer.HorizontalScrollMode="Disabled">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListViewItem">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Height="40">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="50" />
</Grid.ColumnDefinitions>
<TextBlock Text="Sample Text" FontSize="17" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="10,10,0,0" Canvas.ZIndex="10"/>
<Image PointerPressed="Button_Click_1" Grid.Column="1" HorizontalAlignment="Right" VerticalAlignment="Center" Source="Assets/arrw_right.png" Stretch="None" Margin="0,0,10,0"/>
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListView.ItemContainerStyle>
<ListViewItem />
</ListView>
<ListView Grid.Row="1"
IsHitTestVisible="True"
CanDragItems="True"
CanReorderItems="True"
AllowDrop="True"
Name="ChildItems"
SelectionMode="None"
IsItemClickEnabled="False">
<ListView.ItemTemplate>
<DataTemplate>
<local:CollapseUserControl CurrentItem="{Binding RelativeSource={RelativeSource Self}}" />
</DataTemplate>
</ListView.ItemTemplate>
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="Padding" Value="0"/>
<Setter Property="Margin" Value="0"/>
</Style>
</ListView.ItemContainerStyle>
</ListView>
</Grid>
<TextBlock Name="ValueItem" Margin="0,0,0,0" Height="40" FontSize="36"></TextBlock>
</Grid>
New error I get:
Failed to create a 'Windows.UI.Xaml.PropertyPath' from the text ''.
Error comes from <local:CollapseUserControl CurrentItem="{Binding RelativeSource={RelativeSource Self}}" />.

It seems like you can mark your property as internal and then it starts working...
internal static readonly DependencyProperty CurrentItemProperty...
EDIT*
A better approach that seems to be what the platform controls do is to have an actual CLR property that exposes the DependencyProperty object - something like this:
private static readonly DependencyProperty CurrentItemPropertyField =
DependencyProperty.Register/RegisterAttached(...);
internal static DependencyProperty CurrentItemProperty
{
get
{
return CurrentItemPropertyField;
}
}
This allows tools such as Blend to discover the properties.

You can use an automatic property setting the default value (from c# 5) like this:
public static DependencyProperty CurrentItemPropertyField { get; } =
DependencyProperty.Register("Value", typeof(string), typeof(MyControl), new PropertyMetadata("{No Value}"));
Works also for UWP applications

Binding Issues in XAML

I am trying to build a UserControl but I am having trouble getting my bindings to work. I know I am missing something, but I can't figure out what it is. I am not getting any BindingExpressions
XAML
<UserControl x:Class="WpfApplication3.NumericUpDown"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:WpfApplication3">
<Grid>
<StackPanel>
<TextBox Text="{Binding NumericUpDownText, Mode=TwoWay, RelativeSource={RelativeSource AncestorType={x:Type local:NumericUpDown}}}" LostFocus="PART_NumericUpDown_LostFocus">
<TextBox.Resources>
<Style TargetType="TextBox">
<Style.Triggers>
<DataTrigger Binding="{Binding AnyNumericErrors, RelativeSource={RelativeSource AncestorType={x:Type local:NumericUpDown}, AncestorLevel=1}}" Value="false">
<Setter Property="Background" Value="Blue" />
</DataTrigger>
<DataTrigger Binding="{Binding AnyNumericErrors, RelativeSource={RelativeSource AncestorType={x:Type local:NumericUpDown}, AncestorLevel=1}}" Value="true">
<Setter Property="Background" Value="Red" />
<Setter Property="ToolTip" Value="There is an error" />
</DataTrigger>
</Style.Triggers>
<EventSetter Event="LostFocus" Handler="PART_NumericUpDown_LostFocus" />
</Style>
</TextBox.Resources>
<TextBox.Template>
<ControlTemplate>
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<ScrollViewer x:Name="PART_ContentHost"
Grid.Column="0" />
<Grid Grid.Column="1">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<RepeatButton x:Name="PART_IncreaseButton"
Click="PART_IncreaseButton_Click"
Content="UP" />
<RepeatButton x:Name="PART_DecreaseButton"
Grid.Row="1"
Click="PART_DecreaseButton_Click"
Content="Down"/>
</Grid>
</Grid>
</Border>
</ControlTemplate>
</TextBox.Template>
</TextBox>
</StackPanel>
</Grid>
C# Code Behind
namespace WpfApplication3
{
/// <summary>
/// Interaction logic for NumericUpDown.xaml
/// </summary>
public partial class NumericUpDown : UserControl
{
public NumericUpDown()
{
InitializeComponent();
//AnyNumericErrors = true;
}
private String _NumericUpDownText;
public String NumericUpDownText
{
get { return _NumericUpDownText; }
set
{
_NumericUpDownText = value;
NotifyPropertyChanged("NumericUpDownText");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(String propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private void PART_NumericUpDown_LostFocus(object sender, RoutedEventArgs e)
{
CheckForErrors();
}
public void CheckForErrors()
{
try
{
int value = Int32.Parse(NumericUpDownText);
AnyNumericErrors = false;
}
catch (FormatException)
{
Debug.WriteLine("error");
AnyNumericErrors = true;
}
}
private Boolean m_AnyNumericErrors;
public Boolean AnyNumericErrors
{
get
{
return m_AnyNumericErrors;
}
set
{
m_AnyNumericErrors = value;
NotifyPropertyChanged("AnyNumericErrors");
}
}
#region DP
public Int32 LowerBound
{
get;
set;
}
public static readonly DependencyProperty LowerBoundProperty = DependencyProperty.Register("LowerBound", typeof(Int32), typeof(NumericUpDown));
#endregion
private void PART_IncreaseButton_Click(object sender, RoutedEventArgs e)
{
try
{
Int32 value = Int32.Parse(NumericUpDownText);
value++;
NumericUpDownText = value.ToString();
}
catch (Exception)
{
AnyNumericErrors = true;
}
}
private void PART_DecreaseButton_Click(object sender, RoutedEventArgs e)
{
try
{
Int32 value = Int32.Parse(NumericUpDownText);
value--;
NumericUpDownText = value.ToString();
}
catch (Exception)
{
AnyNumericErrors = true;
}
}
}
}
EDIT
The primary issue is that the DataTriggers are not working... at inception, the textbox is blue, but never changes. And when I press on up/down to increment/decrement the values, the events are getting called, but the value isn't changing in the UI

You should use DependencyProperties like:
public bool AnyNumericErrors
{
get { return (bool)GetValue(AnyNumericErrorsProperty); }
set { SetValue(AnyNumericErrorsProperty, value); }
}
// Using a DependencyProperty as the backing store for AnyNumericErrors. This enables animation, styling, binding, etc...
public static readonly DependencyProperty AnyNumericErrorsProperty =
DependencyProperty.Register("AnyNumericErrors", typeof(bool), typeof(NumericUpDown), new UIPropertyMetadata(false));
If that isn't enough, then remove the level restriction on you ancestor search.