OK,
I have a data template for items:
<DataTemplate x:Key="SmallDayEventItemTemplate">
<Border ...>
<Grid ...>
<TextBlock ...
Text="{Binding Path=Title}"/>
<my:SmallPlayer ...
PlayerSource="{Binding Path=MediaSource}">
</my:SmallPlayer>
</Grid>
</Border>
</DataTemplate>
Also i have a UserControl named SmallPlayer.
In SmallPlayer.xaml.cs:
public Uri PlayerSource
{
get { return (Uri)GetValue(PlayerSourceProperty); }
set
{
SetValue(PlayerSourceProperty, value);
//player.Open(value);
}
}
public static readonly DependencyProperty PlayerSourceProperty =
DependencyProperty.Register("PlayerSource", typeof(Uri), typeof(SmallPlayer));
So when i feed MediaSource of an item inside owner window code, item's set accessor gets called but, SmallPlayer's PlayerSource's set accessor never gets called! This is while TextBlock which is bind to Title property acts as expected!
Uri uri = null;
if (Uri.TryCreate(mediaName, UriKind.RelativeOrAbsolute, out uri))
item.MediaSource = uri;
It make me confuse! What's wrong?
The CLR wrapper for a dependency property is never guaranteed to be called, so should never contain any extraneous logic. If you need extra logic when the dependency property is changed, use dependency property metadata. And specifically, the property changed callback.
Related
I have a Custom user control in a silver light Project.
I use it in other page and want to Pass textbox to Custom User control.
For this I create dependcy as below :
public static readonly DependencyProperty MyPropertyProperty = DependencyProperty.Register("TextBoxControl", typeof(TextBox), typeof(SpellCheck), new PropertyMetadata(false));
public TextBox TextBoxControl
{
get { return (TextBox)GetValue(MyPropertyProperty); }
set
{
SetValue(MyPropertyProperty, value);
TextSpell = value;
}
}
Here TextSpell is a textbox.
And I use this property in a silver light page as below:
<TextBox x:Name="txtNote" Grid.Row="3" Grid.Column="1" HorizontalAlignment="Left" VerticalAlignment="Stretch" Width="400"/>
<myButton:SpellCheck x:Name="btnSpell" Grid.Row="3" TextBoxControl="txtNote" Grid.Column="1" Width="20" Height="20" Margin="403,0,0,0" HorizontalAlignment="Left"/>
But I give s me a error : "The Typeconvertor for Texbox dose not support converting from a string"
So How can I pass a text box in custom usercontrol.
Thanks,
Hitesh
You can not simply use the field name (x:Name) string of the TextBox as a value for your TextBoxControl property. Instead you may use an ElementName binding like this:
<myButton:SpellCheck TextBoxControl="{Binding ElementName=txtNote}" ... />
And there are more things wrong:
In the CLR wrappers of a dependency property, you should never call anything else than GetValue and SetValue. The explanation is given in the XAML Loading and Dependency Properties article on MSDN. Instead, you have to have a PropertyChangedCallback registered with the property metadata.
There is a naming convention for the static dependency property fields. They should be named like the property, with a trailing Property.
The default value has to match the property type. Your false value is not valid, and might be null instead. But as that is the default anyway, you should leave it out completely.
The declaration would now look like this:
public static readonly DependencyProperty TextBoxControlProperty =
DependencyProperty.Register(
"TextBoxControl", typeof(TextBox), typeof(SpellCheck),
new PropertyMetadata(TextBoxControlPropertyChanged));
public TextBox TextBoxControl
{
get { return (TextBox)GetValue(TextBoxControlProperty); }
set { SetValue(TextBoxControlProperty, value); }
}
private static void TextBoxControlPropertyChanged(
DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
var spellCheck = (SpellCheck)obj;
spellCheck.TextSpell = (TextBox)e.NewValue;
}
I have a little problem here. I've created custom TreeView using RadTreeView. It all works nice, but I've encountered an obstacle. I've set DependencyProperty for SelectedItem in TreeView. I nest my control in View, bind property to SelectedItem in TwoWay mode, but bound property won't update, it's null all the time, despite DependencyProperty value being set.
Here's tree xaml:
<Grid xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
xmlns:sdk='http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk'
xmlns:telerik='http://schemas.telerik.com/2008/xaml/presentation' x:Name='this' >
<Grid.Resources>
<DataTemplate x:Key='ChildTemplate'>
<TextBlock Text='{Binding Path=ChildPath}' Margin='5,0' />
</DataTemplate>
<telerik:HierarchicalDataTemplate x:Key='NameTemplate' ItemsSource='{Binding ChildrenCollectionPath}' ItemTemplate='{StaticResource ChildTemplate}'>
<TextBlock Text='{Binding Path=ParentPath }' Padding='7'/>
</telerik:HierarchicalDataTemplate>
</Grid.Resources>
<telerik:RadTreeView x:Name='rtvTreeView' Padding='5' BorderThickness='0' IsEditable='False' IsLineEnabled='True' IsExpandOnDblClickEnabled='False' ItemTemplate='{StaticResource NameTemplate}' />
</Grid>
Below is way I nest the control in View:
<windows:TreeViewReuse CollectionSource="{Binding SitesCollectionWithAddress}" ParentPath="Napis" Grid.Column="0" BorderThickness="2" SelectedItemD="{Binding SelectedSide, ElementName=this, UpdateSourceTrigger=Explicit, Mode=TwoWay}" ChildPath="FullAddress" ChildrenCollectionPath="AdresyStrony" BorderBrush="Red" DoubleClickCommand="{Binding TreeViewDoubleClick}">
</windows:TreeViewReuse>
And here's Tree's code behind in parts:
public partial class TreeViewReuse : UserControl
{
static Telerik.Windows.FrameworkPropertyMetadata propertyMetaData = new Telerik.Windows.FrameworkPropertyMetadata(null,
Telerik.Windows.FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, new PropertyChangedCallback(SelectedItemChangedCallback));
public object SelectedItemD
{
get { return GetValue(SelectedItemDProperty); }
set { SetValue(SelectedItemDProperty, value); }
}
public static readonly DependencyProperty SelectedItemDProperty =
DependencyProperty.Register("SelectedItemD", typeof(object), typeof(TreeViewReuse), propertyMetaData);
public TreeViewReuse()
{
InitializeComponent();
Loaded += new RoutedEventHandler(TreeViewReuse_Loaded);
}
void treeView_SelectionChanged(object sender, Telerik.Windows.Controls.SelectionChangedEventArgs e)
{
SelectedItemD = _treeView.SelectedItem;
}
static private void SelectedItemChangedCallback(DependencyObject dp, DependencyPropertyChangedEventArgs e)
{
}
Does anyone have an idea why property bound to SelectedItemD does not update? I don't care about setting tree's selected item from it, I only want to set it to selected item.
Here's property:
public StronaSprawy SelectedSide
{
get
{
return _selectedSide;
}
set
{
_selectedSide = value;
}
}
Your Dependency Property looks fine.. all except for that Telerik.Windows.FrameworkPropertyMetadata instance.
Silverlight does not support setting meta data options, so I cant think how the Telerik implementation will achieve that. It is possible that Telerik have their own DP implementation, or even that this type of property meta data only works with their controls.
Try using the standard System.Windows.PropertyMetaData type instead and see if that works for you.
I'm trying to register 3 dependency properties on a Window to control it's formatting. I've looked over and over the code but I must be missing something.
public static readonly DependencyProperty TextColorProperty = DependencyProperty.Register("TextColor", typeof(Color), typeof(WinStickyFingers), new PropertyMetadata(Colors.White));
public Color TextColor {
get { return (Color)base.GetValue(TextColorProperty); }
set { base.SetValue(TextColorProperty, value); }
}
public static readonly DependencyProperty BackgroundColorProperty = DependencyProperty.Register("BackgroundColor", typeof(Color), typeof(WinStickyFingers), new PropertyMetadata(Colors.Black));
public Color BackgroundColor {
get { return (Color)base.GetValue(BackgroundColorProperty); }
set {
base.SetValue(BackgroundColorProperty, value);
}
}
<TextBlock DockPanel.Dock="Top" Text="{Binding Name}" Foreground="{Binding TextColor,Converter={StaticResource DebugConverter}}" Background="{Binding Path=BackgroundColor}" />
I'm using Bea Stollnitz's debugging method but my breakpoint isn't even triggered.
What is the DataContext of the TextBlock? How does it know that it is supposed to bind to the properties on your Window?
You need to either set DataContext to the Window instance, or set the Source (or RelativeSource, or ElementName) properties on your bindings. All of these properties exist as a means of resolving the bound object for your Binding. DataContext is a fallback if none of the others is set, but I'm guessing that you haven't set that either.
How to bind to a WPF dependency property when the datacontext of the page is used for other bindings? (Simple question)
The datacontext of the element needed to be set.
XAML:
<Window x:Class="WpfDependencyPropertyTest.Window1" x:Name="mywindow">
<StackPanel>
<Label Content="{Binding Path=Test, ElementName=mywindow}" />
</StackPanel>
</Window>
C#:
public static readonly DependencyProperty TestProperty =
DependencyProperty.Register("Test",
typeof(string),
typeof(Window1),
new FrameworkPropertyMetadata("Test"));
public string Test
{
get { return (string)this.GetValue(Window1.TestProperty); }
set { this.SetValue(Window1.TestProperty, value); }
}
Also see this related question:
WPF DependencyProperties
In XAML:
Something="{Binding SomethingElse, ElementName=SomeElement}"
In code:
BindingOperations.SetBinding(obj, SomeClass.SomethingProperty, new Binding {
Path = new PropertyPath(SomeElementType.SomethingElseProperty), /* the UI property */
Source = SomeElement /* the UI object */
});
Though usually you will do this the other way round and bind the UI property to the custom dependency property.
Say I have a very simple UserControl that - for all intents and purposes - is nothing more than TextBox:
public partial class FooBox : UserControl
{
public static readonly DependencyProperty FooTextProperty =
DependencyProperty.Register("FooText", typeof(string), typeof(FooBox));
public FooBox()
{
InitializeComponent();
}
public string FooText
{
get { return textBlock.Text; }
set { textBlock.Text = value; }
}
}
<UserControl x:Class="Namespace.FooBox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="300" Width="300">
<Grid>
<TextBlock x:Name="textBlock" />
</Grid>
</UserControl>
On the form it's declared as:
<local:FooBox FooText="{Binding Name}" />
The form's DataContext is set to an object that has a Name property. But this is not working for me. What am I missing?
The "get" and "set" parts of a property declaration in a DependencyProperty aren't actually called by the databinding system of WPF - they're there essentially to satisfy the compiler only.
Instead, change your property declaration to look like this:
public string FooText
{
get { return (string)GetValue(FooTextProperty); }
set { SetValue(FooTextProperty, value); }
}
... and your XAML to:
<UserControl ...
x:Name="me">
<Grid>
<TextBlock Text="{Binding FooText,ElementName=me}" />
</Grid>
</UserControl>
Now your TextBox.Text simply binds directly to the "FooText" property, so you can in turn bind the FooText property to "Name" just like you're currently doing.
Another way is to bind TextBlock.Text to a RelativeSource binding that finds the FooText property on the first ancestor of type "FooBox", but I've found that this is more complex than just giving the control an internal x:Name and using element binding.
Turns out the real problem is I was expecting the WPF framework to set my public property whereupon my code would respond to the changes and render according to the new value. Not so. What WPF does is call SetValue() directly and completely circumvents the public property. What I had to do was receive property change notifications using DependencyPropertyDescriptor.AddValueChanged and respond to that. It looks something like (inside the ctor):
var dpd = DependencyPropertyDescriptor
.FromProperty(MyDependencyProperty, typeof(MyClass));
dpd.AddValueChanged(this, (sender, args) =>
{
// Do my updating.
});