AddHandler Method

DependencyObject.AddHandler Method (DependencyProperty, Object)


Adds a handler for an event of a DependencyObject.

Namespace:   System.Workflow.ComponentModel
Assembly:  System.Workflow.ComponentModel (in System.Workflow.ComponentModel.dll)

public void AddHandler(
	DependencyProperty dependencyEvent,
	object value


Type: System.Workflow.ComponentModel.DependencyProperty

The DependencyProperty.

Type: System.Object

The Object that represents the value of this property. In this case, a Delegate type.

Exception Condition

Either of the arguments is a null reference (Nothing in Visual Basic).


Value is of incorrect Type.


The dependencyEvent represents a non-event DependencyProperty.

When you create a delegate, you identify the method that handles the event. To associate the event with your event handler, add an instance of the delegate to the event. Unless you remove the delegate, the event handler is called whenever the event occurs. Multiple delegates can be added to handle an event. For more information about event-handler delegates, see NIB: Events and Delegates.

Handlers are added and removed using the following code. This code example is part of the Send E-mail SDK sample and is from the SendMailActivity.cs file. For more information, see .bfb5939e-60a9-4037-af4e-2cea9e654669

#region Public Events

[Description("The SendingEmail event is raised before an email is sent through SMTP.")]
public event EventHandler SendingEmail
        base.AddHandler(SendEmailActivity.SendingEmailEvent, value);
        base.RemoveHandler(SendEmailActivity.SendingEmailEvent, value);

.NET Framework
Available since 3.0
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