DependencyObject.AddHandler(DependencyProperty, Object) Method

Definition

Namespace:

System.Workflow.ComponentModel

Assembly:

System.Workflow.ComponentModel.dll

Adds a handler for an event of a DependencyObject.

public:
 void AddHandler(System::Workflow::ComponentModel::DependencyProperty ^ dependencyEvent, System::Object ^ value);

public void AddHandler (System.Workflow.ComponentModel.DependencyProperty dependencyEvent, object value);

member this.AddHandler : System.Workflow.ComponentModel.DependencyProperty * obj -> unit

Public Sub AddHandler (dependencyEvent As DependencyProperty, value As Object)

Parameters

dependencyEvent

DependencyProperty

The DependencyProperty.

value

Object

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

Exceptions

ArgumentNullException

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

ArgumentException

Value is of incorrect Type

-or-

The dependencyEvent represents a non-event DependencyProperty.

Examples

Handlers are added and removed using the following code. This code example is part of the Send Email SDK sample and is from the SendMailActivity.cs file. For more information, see Send Email Activity Sample.

#region Public Events

[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
[Description("The SendingEmail event is raised before an email is sent through SMTP.")]
[Category(EventsCategory)]
[Browsable(true)]
public event EventHandler SendingEmail
{
    add
    {
        base.AddHandler(SendEmailActivity.SendingEmailEvent, value);
    }
    remove
    {
        base.RemoveHandler(SendEmailActivity.SendingEmailEvent, value);
    }
}

#Region "Public Events"

        <DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)> _
        <Description("The SendingEmail event is raised before an email is sent through SMTP.")> _
        <Category(EventsCategory)> _
        <Browsable(True)> _
        Public Custom Event SendingEmail As EventHandler
            AddHandler(ByVal value As EventHandler)
                MyBase.AddHandler(SendEmailActivity.SendingEmailEvent, value)
            End AddHandler

            RemoveHandler(ByVal value As EventHandler)
                MyBase.RemoveHandler(SendEmailActivity.SendingEmailEvent, value)
            End RemoveHandler

            RaiseEvent(ByVal sender As Object, ByVal e As System.EventArgs)

            End RaiseEvent
        End Event

Remarks

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 Handling and Raising Events.