I created a UserControl in WPF and generated some Dependency Properties.
But on one of the Properties i cannot set a Binding in XAML.
internal Visibility ProgressbarVisibility
{
get { return (Visibility)GetValue(ProgressbarVisibilityProperty); }
set { SetValue(ProgressbarVisibilityProperty, value); }
}
internal static readonly DependencyProperty ProgressbarVisibilityProperty =
DependencyProperty.Register("ProgressbarVisibility", typeof(Visibility), typeof(ImportBox), new PropertyMetadata(Visibility.Hidden));
So i get the following Error:
A 'Binding' cannot be set on the 'ProgressbarVisibility' property of
type 'ImportBox'. A 'Binding' can only be set on a DependencyProperty
of a DependencyObject.
When i set the Property "hardcoded" with a fix Value, its no Problem.
The other Dependeny Properties dont throw Errors of this type and i can Bind everthing i want.
internal ImageSource ImageSource
{
get { return (ImageSource)GetValue(ImageSourceProperty); }
set { SetValue(ImageSourceProperty, value); }
}
internal static readonly DependencyProperty ImageSourceProperty =
DependencyProperty.Register("ImageSource", typeof(ImageSource), typeof(ImportBox));
internal string HeaderText
{
get { return (string)GetValue(HeaderTextProperty); }
set { SetValue(HeaderTextProperty, value); }
}
internal static readonly DependencyProperty HeaderTextProperty =
DependencyProperty.Register("HeaderText", typeof(string), typeof(ImportBox));
internal UIElement PresenterContent
{
get { return (UIElement)GetValue(PresenterContentProperty); }
set { SetValue(PresenterContentProperty, value); }
}
internal static readonly DependencyProperty PresenterContentProperty =
DependencyProperty.Register("PresenterContent", typeof(UIElement), typeof(ImportBox));
Make the DependencyProperty as Public will solves your problem...
public Visibility ProgressbarVisibility
{
get { return (Visibility)GetValue(ProgressbarVisibilityProperty); }
set { SetValue(ProgressbarVisibilityProperty, value); }
}
public static readonly DependencyProperty ProgressbarVisibilityProperty =
DependencyProperty.Register("ProgressbarVisibility", typeof(Visibility), typeof(ImportBox), new PropertyMetadata(Visibility.Hidden));
Related
In my xaml I declare a custom object which has a property referencing another custom object:
public class CustomObjectA : FrameworkElement
{
public CustomObjectB InnerObj
{
get { return GetValue(InnerObjProperty); }
set { SetValue(InnerObjProperty, value); }
}
public static readonly DependencyProperty InnerObjProperty =
DependencyProperty.Register("InnerObj",
typeof(CustomObjectB),
typeof(CustomObjectA),
new PropertyMetadata(null));
}
public class CustomObjectB : FrameworkElement
{
public string Data
{
get { return GetValue(DataProperty); }
set { SetValue(DataProperty, value); }
}
public static readonly DependencyProperty DataProperty =
DependencyProperty.Register("Data",
typeof(string),
typeof(CustomObjectB),
new PropertyMetadata(null));
}
Now when I declare these objects in my xaml like this the binding doesn't work:
<my:CustomObjectA>
<my:CustomObjectA.InnerObj>
<my:CustomObjectB Data="{Binding someValue}" />
</my:CustomObjectA.InnerObj>
</my:CustomObjectA>
However when I declare these objects in my xaml like this the binding works:
<my:CustomObjectB x:Name="testObj" Data="{Binding someValue}" />
<my:CustomObjectA InnerObj="{Binding ElementName=testObj}" />
I'm assuming this is because the system mapping the bindings doesn't look past the top level object. My question is; is there a way to tell the system to evaluate binding expressions beyond the top level custom object so xaml like option 1 will work?
The DataContext is not passed down to the InnerObj. I got it to work by updating the DataContext when the InnerObj changes:
public class CustomObjectA : FrameworkElement
{
public CustomObjectB InnerObj
{
get { return (CustomObjectB)GetValue(InnerObjProperty); }
set { SetValue(InnerObjProperty, value); }
}
public static readonly DependencyProperty InnerObjProperty =
DependencyProperty.Register("InnerObj",
typeof(CustomObjectB),
typeof(CustomObjectA),
new FrameworkPropertyMetadata(OnInnerObjUpdated));
private static void OnInnerObjUpdated(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var local = (CustomObjectA)d;
var newObj = (CustomObjectB)e.NewValue;
newObj.DataContext = local.DataContext;
}
}
I am writing two dependency properties and I keep getting the "[Property] was already registered by 'FrameworkElement'" error in the design window of VS11. Here is a snippet of my code
public static readonly DependencyProperty IsEditingNumberProperty =
DependencyProperty.Register("IsEditingNumbers", typeof(bool), typeof(FrameworkElement),
new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender));
the problem seems to be the 3rd parameter (owner parameter typeof(FrameworkElement)). If I set the 3rd parameter to the class the contains two dependency properties, the error goes away, but I cannot use the properties directly from xaml. I would have to add ownership for each dependency property before I use it.
Actually, It does render correctly, but only when I first open it. Immediately after the first render it will give me an exception. At runtime, it seems to work perfectly.
Am I doing something wrong and is there a way to get rid of this annoying error?
---- Edit -----
Here is my custom class (includes 2 of the Dependency Properties):
public partial class EditableTextBox : UserControl
{
#region Dependency Properties
public static readonly DependencyProperty IsEditingNumberProperty =
DependencyProperty.Register("IsEditingNumber", typeof(bool), typeof(FrameworkElement),
new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender));
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(FrameworkElement),
new FrameworkPropertyMetadata("0", FrameworkPropertyMetadataOptions.AffectsRender)
{
CoerceValueCallback = new CoerceValueCallback((sender,value) =>
{
return expressionRestaraint.Match((string)value).Value;
})
});
#endregion
public static Regex expressionRestaraint = new Regex("[-a-zA-z0-9+*.\\(\\)\\[\\]\\{\\}]*");
public string Text
{
get { (string)GetValue(TextProperty); }
set
{
SetValue(TextProperty, value);
tbxValue.Text = (string)GetValue(TextProperty);
}
}
public bool IsEditingNumber
{
get
{
return (bool)GetValue(IsEditingNumberProperty);
}
set
{
bool old = (bool)GetValue(IsEditingNumberProperty);
if (old != value)
{
if (!value)
stopEditing();
else
startEditing();
SetValue(IsEditingNumberProperty, value);
}
}
} . . .
Use in Main Class:
<Window x:Class="VisualMathExpression.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:edit="clr-namespace:VisualMathExpression.EditableTextBox"
xmlns:all="clr-namespace:VisualMathExpression"
Title="MainWindow" Height="350" Width="525">
<StackPanel>
<edit:EditableTextBox HorizontalAlignment="Center" VerticalAlignment="Center"
Text="af" IsEditingNumber="True" /> . . .
--- Edit ---
Wrapper fixed (problem that cause xaml property not to change when ownership belonged to the declared class)
public partial class EditableTextBox : UserControl
{
#region Dependency Properties
public static readonly DependencyProperty IsEditingNumberProperty =
DependencyProperty.Register("IsEditingNumber", typeof(bool), typeof(EditableTextBox),
new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender)
{
PropertyChangedCallback = new PropertyChangedCallback((sender, arg) =>
{
EditableTextBox ed = sender as EditableTextBox;
if (!(bool)arg.NewValue)
ed.stopEditing();
else
ed.startEditing();
}),
});
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(EditableTextBox),
new FrameworkPropertyMetadata("0", FrameworkPropertyMetadataOptions.AffectsRender)
{
PropertyChangedCallback = new PropertyChangedCallback((sender,arg) =>
{
EditableTextBox ed = sender as EditableTextBox;
ed.tbxValue.Text = arg.NewValue as string;
}),
CoerceValueCallback = new CoerceValueCallback((sender,value) =>
{
return expressionRestaraint.Match((string)value).Value;
})
});
#endregion
public static Regex expressionRestaraint = new Regex("[-a-zA-z0-9+*.\\(\\)\\[\\]\\{\\}]*");
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public bool IsEditingNumber
{
get { return (bool)GetValue(IsEditingNumberProperty); }
set { SetValue(IsEditingNumberProperty, value); }
}
The third parameter ownerType of the DependencyProperty.Register method must be the class that declares the property.
If your class is MyClass the declaration would have to look like this:
public class MyClass : DependencyObject
{
public static readonly DependencyProperty IsEditingNumberProperty =
DependencyProperty.Register(
"IsEditingNumber", typeof(bool), typeof(MyClass), ...);
// CLR wrapper
public bool IsEditingNumber
{
get { return (bool)GetValue(IsEditingNumberProperty); }
set { SetValue(IsEditingNumberProperty, value); }
}
}
I have set up my own user control which contains two ComboBoxes, each ComboBox item source is bound to a DependencyProperty. The issue I am having is passing a property from the form that uses my user control to the user control.
Below is my user control:
public static readonly DependencyProperty ListOneProperty = DependencyProperty.Register
("ListOne", typeof(List<int>), typeof(LinkedComboBox), new PropertyMetadata(new List<int>()));
public List<int> ListOne
{
get { return (List<int>)GetValue(ListOneProperty); }
set { SetValue(ListOneProperty, value); }
}
public static readonly DependencyProperty ListTwoProperty = DependencyProperty.Register
("ListTwo", typeof(List<string>), typeof(LinkedComboBox), new PropertyMetadata(new List<string>()));
public List<string> ListTwo
{
get { return (List<string>)GetValue(ListTwoProperty); }
set { SetValue(ListTwoProperty, value); }
}
public LinkedComboBox()
{
InitializeComponent();
FillListOne();
}
And below is my MainWindow xaml:
<control:LinkedComboBox x:Name="LinkedBox" ListTwo="{Binding MyList}"/>
And MainWindow.xaml.cs:
static List<string> _myList = new List<string>{"abc","efg"};
public List<string> MyList
{
get { return _myList; }
set { _myList = value; }
}
public MainWindow()
{
InitializeComponent();
}
What do I need to get the User Control to accept a binding from the Main Window?
Everything is fine except that you need a PropertyChangedCallback to handle your property.
Here is a simple example
public static readonly DependencyProperty ListTwoProperty = DependencyProperty.Register
("ListTwo", typeof(List<string>), typeof(LinkedComboBox), new PropertyMetadata(new List<string>(), new PropertyChangedCallback(Changed)));
private static void Changed(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
//e.NewValue here is your MyList in MainWindow.
}
I have usercontrol, and there is a DependencyProperty defined in it.
#region ImageUri
public static readonly DependencyProperty ImageUriProperty = DependencyProperty.Register(
"ImageUri",
typeof(string),
typeof(ScrollableCanvas),
new PropertyMetadata(new PropertyChangedCallback(ImageUriPropertyChangedCallback)));
private static void ImageUriPropertyChangedCallback(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
ScrollableCanvas main = sender as ScrollableCanvas;
if (main != null)
{
main.ImageUri = (string)e.NewValue;
}
}
public string ImageUri
{
get
{
return (string)GetValue(ImageUriProperty);
}
set
{
SetValue(ImageUriProperty, value);
UpdateImage();
}
}
#endregion
In the Xaml, I bind a value to it like this
<my:ScrollableCanvas Name="scrollableCanvas1" ImageUri="{Binding Path=LayerImage}" />
when I update the LayerImage in the viewmodel, the ImageUri property does not update.
Can some help on this? Thanks.
BTW: The value is updated when I set the LayerImage in the constructor of the viewmodel.
You shouldn't include your UpdateImage call in your setter, but rather in the property changed callback.
public static readonly DependencyProperty ImageUriProperty = DependencyProperty.Register(
"ImageUri",
typeof(string),
typeof(ScrollableCanvas),
new PropertyMetadata(new PropertyChangedCallback(ImageUriPropertyChangedCallback)));
private static void ImageUriPropertyChangedCallback(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
ScrollableCanvas main = sender as ScrollableCanvas;
if (main != null)
{
// Since ImageUri has already been called at this point, you can just update your image here...
main.UpdateImage();
}
}
public string ImageUri
{
get
{
return (string)GetValue(ImageUriProperty);
}
set
{
SetValue(ImageUriProperty, value);
}
}
I'm using C# 4.0 and have created a DependencyObject MyView.
In MyView, I have two DependencyProperties, PropA and PropB, both are booleans.
I want a third DependencyProperty, PropC, also a bool, and simply put, should always give me (PropA || PropB).
What is the best way to accomplish this?
I was also thinking of making PropC a readonly DependencyProperty, but have read about issues with binding to readonly dp's (WPF ReadOnly Dependency Properties using MVVM)
You can use the Dependency Property changed callback for PropA and PropB to set the value for PropC (don't use the CLR property wrapper for the Dependency Properties as they are never guaranteed to be called).
If you have these three DP's
public static readonly DependencyProperty PropAProperty =
DependencyProperty.Register("PropA",
typeof(bool),
typeof(MyView),
new PropertyMetadata(false, PropAPropertyChanged));
public static readonly DependencyProperty PropBProperty =
DependencyProperty.Register("PropB",
typeof(bool),
typeof(MyView),
new PropertyMetadata(false, PropBPropertyChanged));
public static readonly DependencyProperty PropCProperty =
DependencyProperty.Register("PropC",
typeof(bool),
typeof(MyView),
new PropertyMetadata(false));
public bool PropA
{
get { return (bool)this.GetValue(PropAProperty); }
set { this.SetValue(PropAProperty, value); }
}
public bool PropB
{
get { return (bool)this.GetValue(PropBProperty); }
set { this.SetValue(PropBProperty, value); }
}
public bool PropC
{
get { return (bool)this.GetValue(PropCProperty); }
set { this.SetValue(PropCProperty, value); }
}
you can use the property changed callback like this
private static void PropAPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
{
MyView myView = source as MyView;
myView.OnPropChanged();
}
private static void PropBPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
{
MyView myView = source as MyView;
myView.OnPropChanged();
}
public void OnPropChanged()
{
PropC = PropA || PropB;
}
This way, you'll always update the value of PropC everytime PropA or PropB changes
Also, PropC doesn't need to be a DP, it can be a normal CLR property if you implement INotifyPropertyChanged. Then the implementation can look like this instead
public void OnPropChanged()
{
OnPropertyChanged("PropC");
}
public bool PropC
{
get
{
return PropA || PropB;
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
You could also bind PropC to PropA and PropB with a MultiBinding. Let me know if you want an example of this as well
The linked web page is for an unusual situation, a "push" binding. That is, a one-way-to-source binding was attempted on the read-only property, not on another property trying to bind to it. By contrast, if you want your property to be bindable to other properties using a one-way binding expression on the other property, then you can use a read-only dependency property without any issues.
Edit:
Here is an example:
<Grid>
<Grid.Resources>
<local:MyObject x:Key="myObject" PropertyA="True" PropertyB="False"/>
</Grid.Resources>
<StackPanel DataContext="{StaticResource myObject}">
<CheckBox IsChecked="{Binding PropertyA}" Content="PropertyA"/>
<CheckBox IsChecked="{Binding PropertyB}" Content="PropertyB"/>
<CheckBox IsChecked="{Binding PropertyC, Mode=OneWay}" IsEnabled="False" Content="PropertyC"/>
</StackPanel>
</Grid>
and the dependency properties, one of which is read-only:
public class MyObject : DependencyObject
{
public bool PropertyA
{
get { return (bool)GetValue(PropertyAProperty); }
set { SetValue(PropertyAProperty, value); }
}
public static readonly DependencyProperty PropertyAProperty =
DependencyProperty.Register("PropertyA", typeof(bool), typeof(MyObject), new UIPropertyMetadata(false, OnPropertyAOrBChanged));
public bool PropertyB
{
get { return (bool)GetValue(PropertyBProperty); }
set { SetValue(PropertyBProperty, value); }
}
public static readonly DependencyProperty PropertyBProperty =
DependencyProperty.Register("PropertyB", typeof(bool), typeof(MyObject), new UIPropertyMetadata(false, OnPropertyAOrBChanged));
public bool PropertyC
{
get { return (bool)GetValue(PropertyCProperty); }
set { SetValue(PropertyCPropertyKey, value); }
}
private static readonly DependencyPropertyKey PropertyCPropertyKey =
DependencyProperty.RegisterReadOnly("PropertyC", typeof(bool), typeof(MyObject), new UIPropertyMetadata());
public static readonly DependencyProperty PropertyCProperty = PropertyCPropertyKey.DependencyProperty;
private static void OnPropertyAOrBChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var myObject = d as MyObject;
myObject.PropertyC = myObject.PropertyA || myObject.PropertyB;
}
}