I am trying to write a customer behavior to set some column widths to 0 if my "Visibility" (which is just a bool in this case) property is false... My problem is that when my on changed event fires it my AssociatedObject is always null.
Here is the relevant sample code, mybe someone can see where I am going wrong.
public static readonly DependencyProperty VisibilityProperty =
DependencyProperty.Register("Visibility", typeof(bool), typeof(HideRadGridViewColumnBehavior),
new PropertyMetadata(OnVisibilityPropertyChanged));
private static void OnVisibilityPropertyChanged(DependencyObject target, DependencyPropertyChangedEventArgs args)
{
if (((HideRadGridViewColumnBehavior)target).AssociatedObject == null)
MessageBox.Show("AssociatedObject is null");
}
Thanks for any help...
how are you attaching the behavior? and can you show some code of the behavior?
the AssociatedObject is set either after the call to Attach or through listing the behavior within <i:Interaction.Behaviors></i:Interaction.Behaviors>
Thanks Markus Hütter for idea. This is how I have implemented in PasswordBox Behaviour (see comments in code below):
<PasswordBox>
<i:Interaction.Behaviors>
<behaviours:PasswordBehavior Password="{Binding Password, Mode=TwoWay}" />
</i:Interaction.Behaviors>
</PasswordBox>
Behaviour:
public class PasswordBehavior : Behavior<PasswordBox>
{
public static readonly DependencyProperty PasswordProperty =
DependencyProperty.Register("Password", typeof(string), typeof(PasswordBehavior), new PropertyMetadata(default(string)));
private object _value;
private bool _skipUpdate;
public string Password
{
get { return (string)GetValue(PasswordProperty); }
set { SetValue(PasswordProperty, value); }
}
protected override void OnAttached()
{
// in my case on OnAttached() called after OnPropertyChanged
base.OnAttached();
AssociatedObject.PasswordChanged += PasswordBox_PasswordChanged;
// using _value saved before in OnPropertyChanged
if (_value != null)
{
AssociatedObject.Password = _value as string;
}
}
protected override void OnDetaching()
{
AssociatedObject.PasswordChanged -= PasswordBox_PasswordChanged;
base.OnDetaching();
}
protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e)
{
// in my case this called before OnAttached(), so that's why AssociatedObject is null on first call
base.OnPropertyChanged(e);
if (AssociatedObject == null)
{
// so, let'save the value and then reuse it when OnAttached() called
_value = e.NewValue as string;
return;
}
if (e.Property == PasswordProperty)
{
if (!_skipUpdate)
{
_skipUpdate = true;
AssociatedObject.Password = e.NewValue as string;
_skipUpdate = false;
}
}
}
private void PasswordBox_PasswordChanged(object sender, RoutedEventArgs e)
{
_skipUpdate = true;
Password = AssociatedObject.Password;
_skipUpdate = false;
}
}
Related
I know I need to call RemoveValueChanged, but I have not been able to find a reliable place to call this. I'm learning that there probably isn't one.
I looks like I need to find a different way to monitor the change then adding a handler using AddValueChanged. I'm looking for advice on the best way to achieve this. I've seen the recommendation of using a PropertyChangedCallback in the PropertyMetadata, but I'm not sure how to do this when my TextBox and Adorner are not static. Also, the IsFocused property is not a DependencyProperty created in my class.
public sealed class WatermarkTextBoxBehavior
{
private readonly TextBox m_TextBox;
private TextBlockAdorner m_TextBlockAdorner;
private WatermarkTextBoxBehavior(TextBox textBox)
{
if (textBox == null)
throw new ArgumentNullException("textBox");
m_TextBox = textBox;
}
#region Behavior Internals
private static WatermarkTextBoxBehavior GetWatermarkTextBoxBehavior(DependencyObject obj)
{
return (WatermarkTextBoxBehavior)obj.GetValue(WatermarkTextBoxBehaviorProperty);
}
private static void SetWatermarkTextBoxBehavior(DependencyObject obj, WatermarkTextBoxBehavior value)
{
obj.SetValue(WatermarkTextBoxBehaviorProperty, value);
}
private static readonly DependencyProperty WatermarkTextBoxBehaviorProperty =
DependencyProperty.RegisterAttached("WatermarkTextBoxBehavior",
typeof(WatermarkTextBoxBehavior), typeof(WatermarkTextBoxBehavior), new UIPropertyMetadata(null));
public static bool GetEnableWatermark(TextBox obj)
{
return (bool)obj.GetValue(EnableWatermarkProperty);
}
public static void SetEnableWatermark(TextBox obj, bool value)
{
obj.SetValue(EnableWatermarkProperty, value);
}
public static readonly DependencyProperty EnableWatermarkProperty =
DependencyProperty.RegisterAttached("EnableWatermark", typeof(bool),
typeof(WatermarkTextBoxBehavior), new UIPropertyMetadata(false, OnEnableWatermarkChanged));
private static void OnEnableWatermarkChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.OldValue != null)
{
var enabled = (bool)e.OldValue;
if (enabled)
{
var textBox = (TextBox)d;
var behavior = GetWatermarkTextBoxBehavior(textBox);
behavior.Detach();
SetWatermarkTextBoxBehavior(textBox, null);
}
}
if (e.NewValue != null)
{
var enabled = (bool)e.NewValue;
if (enabled)
{
var textBox = (TextBox)d;
var behavior = new WatermarkTextBoxBehavior(textBox);
behavior.Attach();
SetWatermarkTextBoxBehavior(textBox, behavior);
}
}
}
private void Attach()
{
m_TextBox.Loaded += TextBoxLoaded;
m_TextBox.TextChanged += TextBoxTextChanged;
m_TextBox.DragEnter += TextBoxDragEnter;
m_TextBox.DragLeave += TextBoxDragLeave;
m_TextBox.IsVisibleChanged += TextBoxIsVisibleChanged;
}
private void Detach()
{
m_TextBox.Loaded -= TextBoxLoaded;
m_TextBox.TextChanged -= TextBoxTextChanged;
m_TextBox.DragEnter -= TextBoxDragEnter;
m_TextBox.DragLeave -= TextBoxDragLeave;
m_TextBox.IsVisibleChanged -= TextBoxIsVisibleChanged;
}
private void TextBoxDragLeave(object sender, DragEventArgs e)
{
UpdateAdorner();
}
private void TextBoxDragEnter(object sender, DragEventArgs e)
{
m_TextBox.TryRemoveAdorners<TextBlockAdorner>();
}
private void TextBoxIsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
UpdateAdorner();
}
private void TextBoxTextChanged(object sender, TextChangedEventArgs e)
{
var hasText = !string.IsNullOrEmpty(m_TextBox.Text);
SetHasText(m_TextBox, hasText);
}
private void TextBoxLoaded(object sender, RoutedEventArgs e)
{
Init();
}
#endregion
#region Attached Properties
public static string GetLabel(TextBox obj)
{
return (string)obj.GetValue(LabelProperty);
}
public static void SetLabel(TextBox obj, string value)
{
obj.SetValue(LabelProperty, value);
}
public static readonly DependencyProperty LabelProperty =
DependencyProperty.RegisterAttached("Label", typeof(string), typeof(WatermarkTextBoxBehavior));
public static Style GetLabelStyle(TextBox obj)
{
return (Style)obj.GetValue(LabelStyleProperty);
}
public static void SetLabelStyle(TextBox obj, Style value)
{
obj.SetValue(LabelStyleProperty, value);
}
public static readonly DependencyProperty LabelStyleProperty =
DependencyProperty.RegisterAttached("LabelStyle", typeof(Style),
typeof(WatermarkTextBoxBehavior));
public static bool GetHasText(TextBox obj)
{
return (bool)obj.GetValue(HasTextProperty);
}
private static void SetHasText(TextBox obj, bool value)
{
obj.SetValue(HasTextPropertyKey, value);
}
private static readonly DependencyPropertyKey HasTextPropertyKey =
DependencyProperty.RegisterAttachedReadOnly("HasText", typeof(bool),
typeof(WatermarkTextBoxBehavior), new UIPropertyMetadata(false));
public static readonly DependencyProperty HasTextProperty =
HasTextPropertyKey.DependencyProperty;
#endregion
private void Init()
{
m_TextBlockAdorner = new TextBlockAdorner(m_TextBox, GetLabel(m_TextBox), GetLabelStyle(m_TextBox));
UpdateAdorner();
DependencyPropertyDescriptor focusProp = DependencyPropertyDescriptor.FromProperty(UIElement.IsFocusedProperty, typeof(FrameworkElement));
if (focusProp != null)
{
focusProp.AddValueChanged(m_TextBox, (sender, args) => UpdateAdorner());
}
DependencyPropertyDescriptor containsTextProp = DependencyPropertyDescriptor.FromProperty(HasTextProperty, typeof(TextBox));
if (containsTextProp != null)
{
containsTextProp.AddValueChanged(m_TextBox, (sender, args) => UpdateAdorner());
}
}
private void UpdateAdorner()
{
if (GetHasText(m_TextBox) ||
m_TextBox.IsFocused ||
!m_TextBox.IsVisible)
{
// Hide the Watermark Label if the adorner layer is visible
m_TextBox.ToolTip = GetLabel(m_TextBox);
m_TextBox.TryRemoveAdorners<TextBlockAdorner>();
}
else
{
// Show the Watermark Label if the adorner layer is visible
m_TextBox.ToolTip = null;
m_TextBox.TryAddAdorner<TextBlockAdorner>(m_TextBlockAdorner);
}
}
}
AddValueChanged of dependency property descriptor results in memory leak as you already know. So, as described here, you can create custom class PropertyChangeNotifier to listen to any dependency property changes.
Complete implementation can be found here - PropertyDescriptor AddValueChanged Alternative.
Quote from the link:
This class takes advantage of the fact that bindings use weak
references to manage associations so the class will not root the
object who property changes it is watching. It also uses a
WeakReference to maintain a reference to the object whose property it
is watching without rooting that object. In this way, you can maintain
a collection of these objects so that you can unhook the property
change later without worrying about that collection rooting the object
whose values you are watching.
Also for sake of completeness of answer I am posting complete code here to avoid any rot issue in future.
public sealed class PropertyChangeNotifier : DependencyObject, IDisposable
{
#region Member Variables
private readonly WeakReference _propertySource;
#endregion // Member Variables
#region Constructor
public PropertyChangeNotifier(DependencyObject propertySource, string path)
: this(propertySource, new PropertyPath(path))
{
}
public PropertyChangeNotifier(DependencyObject propertySource, DependencyProperty property)
: this(propertySource, new PropertyPath(property))
{
}
public PropertyChangeNotifier(DependencyObject propertySource, PropertyPath property)
{
if (null == propertySource)
throw new ArgumentNullException("propertySource");
if (null == property)
throw new ArgumentNullException("property");
_propertySource = new WeakReference(propertySource);
Binding binding = new Binding
{
Path = property,
Mode = BindingMode.OneWay,
Source = propertySource
};
BindingOperations.SetBinding(this, ValueProperty, binding);
}
#endregion // Constructor
#region PropertySource
public DependencyObject PropertySource
{
get
{
try
{
// note, it is possible that accessing the target property
// will result in an exception so i’ve wrapped this check
// in a try catch
return _propertySource.IsAlive
? _propertySource.Target as DependencyObject
: null;
}
catch
{
return null;
}
}
}
#endregion // PropertySource
#region Value
/// <summary>
/// Identifies the <see cref="Value"/> dependency property
/// </summary>
public static readonly DependencyProperty ValueProperty = DependencyProperty.Register("Value",
typeof(object), typeof(PropertyChangeNotifier), new FrameworkPropertyMetadata(null, OnPropertyChanged));
private static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
PropertyChangeNotifier notifier = (PropertyChangeNotifier)d;
if (null != notifier.ValueChanged)
notifier.ValueChanged(notifier, EventArgs.Empty);
}
/// <summary>
/// Returns/sets the value of the property
/// </summary>
/// <seealso cref="ValueProperty"/>
[Description("Returns/sets the value of the property")]
[Category("Behavior")]
[Bindable(true)]
public object Value
{
get
{
return GetValue(ValueProperty);
}
set
{
SetValue(ValueProperty, value);
}
}
#endregion //Value
#region Events
public event EventHandler ValueChanged;
#endregion // Events
#region IDisposable Members
public void Dispose()
{
BindingOperations.ClearBinding(this, ValueProperty);
}
#endregion
}
A more lightweight solution for FrameworkElements and FrameworkContentElements is to subscribe to the Unloaded event and remove the handler. This requires a non-anonymous delegate (UpdateAdorner in that case) though:
focusProp.AddValueChanged(m_TextBox, UpdateAdorner);
m_TextBox.Unloaded += (sender, args) => focusProp.RemoveValueChanged(sender, UpdateAdorner);
I'm working on a custom behavior for the visiblox chart. This custom behavior has a dependency property Value that identifies the position of a cursor that consists of vertical line draw in the chart. This cursor follows the mouse if I set the property FollowMouse to true.
If I bind the Value property the changedvaluecallback only gets 0 as the newValue, while if the value is not bound it works properly. But if i change the source property of the binding (property on ViewModel) it works too. So the problem is setting the value with SetCurrentValue on PointerMoved.
Here is the source code of the behavior:
public class TimeCursorBehavior : BehaviourWithAxesBase
{
private System.Windows.Shapes.Line _line;
public TimeCursorBehavior()
: base("TimeCursor")
{
_line = new System.Windows.Shapes.Line();
_line.Stroke = System.Windows.Media.Brushes.Black;
_line.StrokeThickness = 2;
}
public override void DeInit()
{
base.DeInit();
Chart.BehaviourCanvas.Children.Remove(_line);
}
protected override void Init()
{
base.Init();
Chart.BehaviourCanvas.Children.Add(_line);
}
public override void PointerMoved(IBehaviourEventSource sender, PointerEventContext context)
{
base.PointerMoved(sender, context);
if (!FollowMouse)
return;
IComparable xDataValue = XAxis.GetRenderPositionAsDataValueWithZoom(context.Point.X);
SetCurrentValue(ValueProperty, xDataValue);
}
public override void BehaviourCanvasSizeChanged(IBehaviourEventSource sender, SizeChangedEventArgs e)
{
base.BehaviourCanvasSizeChanged(sender, e);
_line.Y2 = e.NewSize.Height;
}
#region Value
public static readonly DependencyProperty ValueProperty = DependencyProperty.Register("Value", typeof(IComparable), typeof(TimeCursorBehavior), new FrameworkPropertyMetadata(0, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnValueChanged));
private static void OnValueChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
{
(sender as TimeCursorBehavior).OnValueChanged(args.OldValue as IComparable, args.NewValue as IComparable);
}
private void OnValueChanged(IComparable oldValue, IComparable newValue)
{
if (XAxis == null)
return;
double x = XAxis.GetDataValueAsRenderPositionWithZoom(newValue);
_line.X1 = x;
_line.X2 = x;
}
public IComparable Value
{
get
{
return GetValue(ValueProperty) as IComparable;
}
set
{
SetValue(ValueProperty, value);
}
}
#endregion
#region FollowMouse
public static readonly DependencyProperty FollowMouseProperty = DependencyProperty.Register("FollowMouse", typeof(bool), typeof(TimeCursorBehavior), new PropertyMetadata(false));
public bool FollowMouse
{
get
{
return (bool)GetValue(FollowMouseProperty);
}
set
{
SetValue(FollowMouseProperty, value);
}
}
#endregion
}
Does anyone know why setcurrentvalue is not updating the value accordingly?
Found the problem.
My property in the ViewModel is an decimal, and the property returned by the line below is a double.
IComparable xDataValue = XAxis.GetRenderPositionAsDataValueWithZoom(context.Point.X);
I added an converter to the binding it everything worked as expected.
I am using Phone7.Fx R1
The following works. The system does not react when a user presses the button. This means, than there is no reaction if Stop Game is pressed without a game has been started and vice versa.
However the button looks active. I am aware that I can bind the IsEnabled to a different property, but I would like it to bind to NewGameCanExecute and StopGameCanExecute. Is this possible?
Some XAML code:
<Preview:BindableApplicationBarIconButton Command="{Binding NewGame}" IconUri="/images/icons/appbar.add.rest.png" Text="New game" />
<Preview:BindableApplicationBarIconButton Command="{Binding StopGame}" IconUri="/images/icons/appbar.stop.rest.png" Text="Stop game" />
And the relay commands:
public RelayCommand NewGame { get; private set; }
public RelayCommand StopGame { get; private set; }
//Constructor
NewGame = new RelayCommand(NewGameExecute, NewGameCanExecute);
StopGame = new RelayCommand(StopGameExecute, StopGameCanExecute);
void NewGameExecute()
{
_gameStarted = true;
_gameControlModel.StartNewGame();
StopGame.RaiseCanExecuteChanged();
}
bool NewGameCanExecute()
{
return !_gameStarted;
}
void StopGameExecute()
{
_gameControlModel.StopGame();
_gameStarted = false;
NewGame.RaiseCanExecuteChanged();
}
bool StopGameCanExecute()
{
return _gameStarted;
}
Couple of questions and answers:
Q: Have you tried to set a breakpoint in the CanExecute functions to see if it gets called?
A: Yes. It does get called, but the icon is not grayed out, eventhough false is returned.
The Execute method is not executed, if the CanExecute method returns false. But I want the icon to be grayed out like a normal button.
SOLUTION
I spend some time and came up with a solution, which can be found here:
http://pastebin.com/MM75xACj
This is obviously a bug in whatever BindableApplicationBarIconButton implementation you're using.
Ask the author of it for help, or debug your 3rd party software yourself.
SOLUTION
I spend some time and came up with a solution and edited the applicationbariconbutton class.
namespace Phone7.Fx.Controls
{
public class BindableApplicationBarIconButton : FrameworkElement, IApplicationBarIconButton
{
public int Index { get; set; }
public static DependencyProperty CommandProperty = DependencyProperty.RegisterAttached("Command", typeof(ICommand), typeof(BindableApplicationBarIconButton), new PropertyMetadata(null, OnCommandPropertyChanged));
private static void OnCommandPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
((BindableApplicationBarIconButton)d).Command = (ICommand)e.NewValue;
}
}
public ICommand Command
{
get { return (ICommand)GetValue(CommandProperty); }
set {
Command.CanExecuteChanged -= ValueOnCanExecuteChanged;
SetValue(CommandProperty, value);
Command.CanExecuteChanged += ValueOnCanExecuteChanged;
}
}
private void ValueOnCanExecuteChanged(object sender, EventArgs eventArgs)
{
ICommand commandSender = sender as ICommand;
if(commandSender != null)
{IsEnabled = commandSender.CanExecute(null);}
}
public static readonly DependencyProperty CommandParameterProperty =
DependencyProperty.RegisterAttached("CommandParameter", typeof(object), typeof(BindableApplicationBarIconButton), new PropertyMetadata(null, OnCommandParameterPropertyChanged));
private static void OnCommandParameterPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var invokeCommand = d as BindableApplicationBarIconButton;
if (invokeCommand != null)
{
invokeCommand.SetValue(CommandParameterProperty, e.NewValue);
}
}
public object CommandParameter
{
get { return GetValue(CommandParameterProperty); }
set
{
SetValue(CommandParameterProperty, value);
}
}
public static readonly DependencyProperty CommandParameterValueProperty =
DependencyProperty.RegisterAttached("CommandParameterValue", typeof(object), typeof(BindableApplicationBarIconButton), null);
public object CommandParameterValue
{
get
{
var returnValue = GetValue(CommandParameterValueProperty);
return returnValue;
}
set { SetValue(CommandParameterValueProperty, value); }
}
public static readonly DependencyProperty IsEnabledProperty =
DependencyProperty.RegisterAttached("IsEnabled", typeof(bool), typeof(BindableApplicationBarIconButton), new PropertyMetadata(true, OnEnabledChanged));
private static void OnEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
((BindableApplicationBarIconButton)d).Button.IsEnabled = (bool)e.NewValue;
}
}
public static readonly DependencyProperty TextProperty =
DependencyProperty.RegisterAttached("Text", typeof(string), typeof(BindableApplicationBarIconButton), new PropertyMetadata(OnTextChanged));
public new static readonly DependencyProperty VisibilityProperty =
DependencyProperty.RegisterAttached("Visibility", typeof(Visibility), typeof(BindableApplicationBarIconButton), new PropertyMetadata(OnVisibilityChanged));
private static void OnVisibilityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
var button = ((BindableApplicationBarIconButton)d);
BindableApplicationBar bar = button.Parent as BindableApplicationBar;
bar.Invalidate();
}
}
public new Visibility Visibility
{
get { return (Visibility)GetValue(VisibilityProperty); }
set { SetValue(VisibilityProperty, value); }
}
private static void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
((BindableApplicationBarIconButton)d).Button.Text = e.NewValue.ToString();
}
}
public ApplicationBarIconButton Button { get; set; }
public BindableApplicationBarIconButton()
{
Button = new ApplicationBarIconButton();
Button.Text = "Text";
Button.Click += ApplicationBarIconButtonClick;
}
void ApplicationBarIconButtonClick(object sender, EventArgs e)
{
if (Command != null && CommandParameter != null)
Command.Execute(CommandParameter);
else if (Command != null)
Command.Execute(CommandParameterValue);
if (Click != null)
Click(this, e);
}
public bool IsEnabled
{
get { return (bool)GetValue(IsEnabledProperty); }
set { SetValue(IsEnabledProperty, value); }
}
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public event EventHandler Click;
public Uri IconUri
{
get { return Button.IconUri; }
set { Button.IconUri = value; }
}
}
I Create a TimeInput Control Like to Enter Time.
<TextBox Text="{Binding Path=Hours}" />
<TextBox IsReadOnly="True"
Focusable="False"
Text=":" />
<TextBox Text="{Binding Path=Minutes}" />
and
public int Hours {
get { return (int)this.GetValue(HoursProperty); }
set {
this.SetValue(HoursProperty, value);
this.OnPropertyChanged("Hours");
}
}
public static readonly DependencyProperty HoursProperty =
DependencyProperty.Register("Hours", typeof(int), typeof(UserControl1), new UIPropertyMetadata(0, new PropertyChangedCallback(OnHoursChanged)));
private static void OnHoursChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) {
if (obj != null) {
int newValue = (int)e.NewValue;
}
}
public int Minutes {
get { return (int)this.GetValue(MinutesProperty); }
set {
this.SetValue(MinutesProperty, value);
this.OnPropertyChanged("Minutes");
}
}
// Using a DependencyProperty as the backing store for Minutes. This enables animation, styling, binding, etc...
public static readonly DependencyProperty MinutesProperty =
DependencyProperty.Register("Minutes", typeof(int), typeof(UserControl1), new UIPropertyMetadata(0, new PropertyChangedCallback(OnMinutesChanged)));
private static void OnMinutesChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) {
if (obj != null) {
int newValue = (int)e.NewValue;
}
}
public Nullable<TimeSpan> Value {
get { return (Nullable<TimeSpan>)this.GetValue(ValueProperty); }
set {
this.SetValue(ValueProperty, value);
this.OnPropertyChanged("Value");
}
}
// Using a DependencyProperty as the backing store for Value. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ValueProperty =
DependencyProperty.Register("Value", typeof(Nullable<TimeSpan>), typeof(UserControl1), new UIPropertyMetadata(null, new PropertyChangedCallback(OnValueChanged)));
private static void OnValueChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) {
if (obj != null) {
(obj as UserControl1).UpdateTime(e.NewValue as TimeSpan?);
}
}
public void UpdateTime(TimeSpan? newTimeSpan) {
if (newTimeSpan.HasValue) {
this.Hours = newTimeSpan.Value.Hours;
this.Minutes = newTimeSpan.Value.Minutes;
}
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name) {
PropertyChangedEventHandler handler = this.PropertyChanged;
if (handler != null) {
handler(this, new PropertyChangedEventArgs(name));
}
}
#endregion
While I use this on another UserControl and Bind to a Property It doesn't work and show values.
I use it like this:
<uc:UserControl1 Value="{Binding StartTime}"/>
and
public TimeSpan StartTime
{
get { return new Types.Time(Item.StartTime).ToTimeSpan(); }
set { Item.StartTime = new Types.Time(value).ToShort(); NotifyPropertyChanged("StartTime"); }
}
That Item is an entity read from database and bind and StartTime is short form of hhmm.
i have updated your code, with dependency properties you don't need fire the property changed event explicit.
public partial class UserControl1 : UserControl
{
public UserControl1() {
this.InitializeComponent();
}
public int Hours {
get { return (int)this.GetValue(HoursProperty); }
set { this.SetValue(HoursProperty, value); }
}
public static readonly DependencyProperty HoursProperty =
DependencyProperty.Register("Hours", typeof(int), typeof(UserControl1), new UIPropertyMetadata(0, new PropertyChangedCallback(OnHoursChanged)));
private static void OnHoursChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) {
var uc = obj as UserControl1;
if (uc != null && e.NewValue != e.OldValue) {
int newValue = (int)e.NewValue;
uc.TimeValue = new TimeSpan(newValue, uc.Minutes, 0);
}
}
public int Minutes {
get { return (int)this.GetValue(MinutesProperty); }
set { this.SetValue(MinutesProperty, value); }
}
// Using a DependencyProperty as the backing store for Minutes. This enables animation, styling, binding, etc...
public static readonly DependencyProperty MinutesProperty =
DependencyProperty.Register("Minutes", typeof(int), typeof(UserControl1), new UIPropertyMetadata(0, new PropertyChangedCallback(OnMinutesChanged)));
private static void OnMinutesChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) {
var uc = obj as UserControl1;
if (uc != null && e.NewValue != e.OldValue) {
int newValue = (int)e.NewValue;
uc.TimeValue = new TimeSpan(uc.Hours, newValue, 0);
}
}
public Nullable<TimeSpan> TimeValue {
get { return (Nullable<TimeSpan>)this.GetValue(ValueProperty); }
set { this.SetValue(ValueProperty, value); }
}
public static readonly DependencyProperty ValueProperty =
DependencyProperty.Register("TimeValue", typeof(Nullable<TimeSpan>), typeof(UserControl1), new UIPropertyMetadata(null, new PropertyChangedCallback(OnValueChanged)));
private static void OnValueChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) {
var uc = obj as UserControl1;
if (uc != null && e.NewValue != e.OldValue) {
uc.UpdateTime(e.NewValue as TimeSpan?);
}
}
public void UpdateTime(TimeSpan? newTimeSpan) {
if (newTimeSpan.HasValue) {
this.Hours = newTimeSpan.Value.Hours;
this.Minutes = newTimeSpan.Value.Minutes;
}
}
}
second, i think you use the StartTime property incorrect, use it as dependency property too, or implement INotifyPropertyChanged.
{
// .....
StartTime = new Types.Time(this.Item.StartTime).ToTimeSpan();
// .....
}
public static readonly DependencyProperty StartTimeProperty =
DependencyProperty.Register("StartTime", typeof(TimeSpan?), typeof(Window1), new PropertyMetadata(default(TimeSpan?), new PropertyChangedCallback(OnStartTimePropertyChanged)));
private static void OnStartTimePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) {
if(e.NewValue != e.OldValue) {
(dependencyObject as Window1).Item.StartTime = new Types.Time(e.NewValue).ToShort();
}
}
public TimeSpan? StartTime {
get { return (TimeSpan?)GetValue(StartTimeProperty); }
set { SetValue(StartTimeProperty, value); }
}
hope this helps
You should not have any other code then calling GetValue and SetValue inside getter and setter of dependency property. But this may not resolve you problem. If you want to call some code when value change then do that inside callback method instead of setter.
OK - So I almost have this working. I just need to know who to get the usercontrol to let the viewmodel of the consuming view know there has been a change. Check this out - here is xaml from the consuming view.
<StackPanel>
<pfControls:TriChoiceUserControl Text="{Binding Path=SampleText}" State="{Binding CurrentState}"/>
</StackPanel>
Here is the viewmodel code
class MainWindowViewModel: INotifyPropertyChanged
{
private bool? currentState;
public bool? CurrentState
{
get { return currentState; }
set {
currentState = value;
OnPropertyChanged("CurrentState");
}
}
public string SampleText { get { return "Hi there"; } }
public MainWindowViewModel()
{
CurrentState = false;
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
Now on the initial load of the ViewModel you can see that Current state is false and indeed the control I ends up with the false check box checked (there are three check boxes, one for yes, one for no and one for na - don't ask me, that is what they told me to do). Problem is that when I check the first one (true in this case) the user control is working in that it goes and unchecks the false check box but and changes the state property but my viewmodel for the consuming view never gets notified. I feel like I am so close... Here is the code for the user control.
public partial class TriChoiceUserControl : UserControl, INotifyPropertyChanged
{
#region Fields (5)
public static readonly DependencyProperty StateProperty = DependencyProperty.Register("State", typeof(bool?), typeof(TriChoiceUserControl),
new FrameworkPropertyMetadata(new PropertyChangedCallback(ChangeState)));
public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(String), typeof(TriChoiceUserControl),
new FrameworkPropertyMetadata(new PropertyChangedCallback(ChangeText)));
#endregion Fields
public TriChoiceUserControl()
{
InitializeComponent();
}
public bool? State
{
get
{
return (bool?)GetValue(StateProperty);
}
set
{
SetValue(StateProperty, value);
NotifyPropertyChanged("State");
}
}
public string Text
{
get
{
return (string)GetValue(TextProperty);
}
set
{
SetValue(TextProperty, value);
}
}
private static void ChangeState(DependencyObject source, DependencyPropertyChangedEventArgs e)
{
(source as TriChoiceUserControl).UpdateCheckState((bool?)e.NewValue);
}
private static void ChangeText(DependencyObject source, DependencyPropertyChangedEventArgs e)
{
(source as TriChoiceUserControl).UpdateText(e.NewValue.ToString());
}
private void UpdateText(string newText)
{
label1.Content = newText;
}
private void UpdateCheckState(bool? newState)
{
if (newState != null)
{
if ((bool)newState)
{
chkYes.IsChecked = true;
chkNo.IsChecked = false;
chkNa.IsChecked = false;
}
else
{
chkYes.IsChecked = false;
chkNo.IsChecked = true;
chkNa.IsChecked = false;
}
}
else
{
chkYes.IsChecked = false;
chkNo.IsChecked = false;
chkNa.IsChecked = true;
}
State = newState;
}
private void chkYes_Checked(object sender, RoutedEventArgs e)
{
UpdateCheckState(true);
}
private void chkNo_Checked(object sender, RoutedEventArgs e)
{
UpdateCheckState(false);
}
private void chkNa_Checked(object sender, RoutedEventArgs e)
{
UpdateCheckState(null);
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
}
Here is the XAML for the user control.
Thanks for any input.
All of this works just fine, I had lost sight of the fact that the default mode is "oneWay" on the binding - duh - I set Mode=TwoWay and no everything works. But that OK, I don't mind saying duh, it usually means I have found the answer :)