DependencyObject.RemoveHandler(DependencyProperty, Object) Method

Definition

Namespace:

System.Workflow.ComponentModel

Assembly:

System.Workflow.ComponentModel.dll

Removes an EventHandler from an associated DependencyProperty.

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

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

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

Public Sub RemoveHandler (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

The dependencyEvent is a metaproperty.

-or-

The dependencyEvent is not an event.

ReadOnlyException

The value is a ActivityBind and this instance is not in DesignMode.

Examples

Handlers are added and removed using the following code. 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

Provided as a convenient direct method for removing an event delegate.

When you create a delegate, you identify the method that will handle 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. For more information about event-handler delegates, see Handling and Raising Events.