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IExpression

Interface

Defines a contract for expression objects that can provide dynamic property values and participate in the RadProperty value resolution system.

Definition

Namespace:Telerik.WinControls

Assembly:Telerik.WinControls.dll

Syntax:

C#
public interface IExpression

Methods

Gets the current value for the specified property on the given RadObject.

C#
object GetValue(RadObject forObject, RadProperty property)
Parameters:forObjectRadObject

The RadObject instance for which to retrieve the property value.

propertyRadProperty

The RadProperty whose value should be retrieved.

Returns:

object

The current value of the property, or UnsetValue if no value is available.

Remarks:

This method is called by the property system when resolving property values. Implementations should return the appropriate value based on their expression logic or UnsetValue to allow fallback to the next value source.

Called when this expression is being attached to the specified property on the given RadObject.

C#
void OnAttach(RadObject radObject, RadProperty dp)
Parameters:radObjectRadObject

The RadObject to which the expression is being attached.

dpRadProperty

The RadProperty to which the expression is being attached.

Remarks:

This method provides an opportunity for expressions to initialize resources, subscribe to events, or perform other setup operations when they begin providing values for a property.

Called when this expression is being removed from the specified property on the given RadObject.

C#
void OnDetach(RadObject radObject, RadProperty dp)
Parameters:radObjectRadObject

The RadObject from which the expression is being detached.

dpRadProperty

The RadProperty from which the expression is being detached.

Remarks:

This method provides an opportunity for expressions to clean up resources, unsubscribe from events, or perform other cleanup operations when they are no longer providing values for a property.

Attempts to set a value through this expression.

C#
bool SetValue(RadObject radObject, RadProperty dp, object value)
Parameters:radObjectRadObject

The RadObject on which to set the property value.

dpRadProperty

The RadProperty to set.

valueobject

The value to set.

Returns:

bool

true if the expression handled the set operation; otherwise, false.

Remarks:

Most expression types are read-only and will return false from this method. Data binding expressions may support two-way binding and return true when they successfully update the underlying data source.