how to override default dependency property metadata. for example ;Text property for textbox. i use this code
class UCTextBox : TextBox
{
public UCTextBox()
{
var defaultMetadata = TextBox.TextProperty.GetMetadata(typeof(TextBox));
TextBox.TextProperty.OverrideMetadata(typeof(UCTextBox),
new FrameworkPropertyMetadata(string.Empty,
FrameworkPropertyMetadataOptions.Journal |
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
defaultMetadata.PropertyChangedCallback,
new CoerceValueCallback(CoerceText)
));
}
private static object CoerceText(DependencyObject d, object value)
{
return value.ToString().Replace(",","");
}
but this In both runs(get,set)
No one can help me!!!:(((
DependencyProperty has to be static (Class level) because when we create multiple objects of the class which has that property and want to refer the default value for that property the value has to come from that static instance of DependencyProperty.
Property metadata can be defined and used during dependency property registration when calling the Register method (or variations for attached properties or read-only dependency properties), or after original owner registration when calling the OverrideMetadata method. AddOwner also takes property metadata.
Arguably the biggest feature of a dependency property is its built-in ability to provide change notification. The motivation for adding such intelligence to properties is to enable rich functionality directly from declarative markup.
Here is an example of a class derived from TextBox
overriding the metadata for the Text
property:
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
public class MyTextBox : TextBox
{
static MyTextBox()
{
TextBox.TextProperty.OverrideMetadata(typeof(MyTextBox),
new FrameworkPropertyMetadata(string.Empty,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault |
FrameworkPropertyMetadataOptions.Journal,
null, /* property changed callback */
null, /* coerce value callback */
true, /* is animation prohibited */
UpdateSourceTrigger.LostFocus));
}
}
Notice that the override is place in the static
constructor, not the ordinary constructor.
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