Namespace:
System.Windows
Assembly:
System.Windows (in System.Windows.dll)
Visual Basic (Declaration)
Public Sub SetValue ( _
dp As DependencyProperty, _
value As Object _
)
Dim instance As DependencyObject
Dim dp As DependencyProperty
Dim value As Object
instance.SetValue(dp, value)
public void SetValue(
DependencyProperty dp,
Object value
)
| Exception | Condition |
|---|
| ArgumentException |
value was not the correct type as registered for the dp property. |
If the provided type does not match the type that is declared for the dependency property as it was originally registered, an exception is thrown. The value parameter should always be provided as the appropriate type.
In contrast, to use the managed code version of SetValue, you must provide input of a DependencyProperty object. You would typically get this value from the public static property that serves as a dependency property identifier, available on the same object that owns the dependency property itself. Note that not all properties are dependency properties, which means that the managed code version of SetValue cannot be used to access all possible properties in the managed API for Silverlight (you can only access dependency properties).
For user code, calling SetValue is not typically necessary. Usually, a Silverlight property or a custom dependency property has a CLR property that wraps it, and you can just set the property value through a conventional CLR usage. There are three notable cases where SetValue is used more typically:
You are defining a custom dependency property. You will call SetValue as part of defining your own property set accessor for the CLR usage. For details, see Custom Dependency Objects and Dependency Properties.
You are defining a callback or are in some other scope where you are already being passed a DependencyProperty identifier, and it is possible that more than one dependency property exists that you might want to interact with in that scope. In these cases it is probably simpler to call SetValue, passing the identifier.
The DependencyProperty identifier references an attached property (or you are not sure whether it is attached property or a dependency property with a CLR wrapper). Attached properties also have dedicated get and set accessors, which are typically more type-safe, but it still might be more convenient to use SetValue if you already have the identifier.
JavaScript API Notes
The JavaScript implementation of SetValue is notably different, primarily because its first parameter's input type is treated as a name string, not as a DependencyProperty object. You can use the JavaScript SetValue method to set the value of any Silverlight property that is available to the JavaScript API. However, you generally do not need this method to set property values, because all Silverlight properties support a more direct "dotted" property syntax in JavaScript.
The following example shows a simple dependency property declaration. A call to SetValue constitutes the entirety of the set accessor implementation for the CLR wrapper of the new dependency property.
public class Fish : Control
{
public static readonly DependencyProperty SpeciesProperty =
DependencyProperty.Register(
"Species",
typeof(string),
typeof(Fish), null
);
public string Species
{
get { return (string)GetValue(SpeciesProperty); }
set { SetValue(SpeciesProperty, (string)value); }
}
}
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
Reference
Other Resources