Articolo
11/18/2011

EventInfo Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Discovers the attributes of an event and provides access to event metadata.

Inheritance Hierarchy

System.Object
System.Reflection.MemberInfo
System.Reflection.EventInfo

Namespace: System.Reflection
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
<ComVisibleAttribute(True)> _
<ClassInterfaceAttribute(ClassInterfaceType.None)> _
Public MustInherit Class EventInfo _
    Inherits MemberInfo

[ComVisibleAttribute(true)]
[ClassInterfaceAttribute(ClassInterfaceType.None)]
public abstract class EventInfo : MemberInfo

The EventInfo type exposes the following members.

Constructors

	Name	Description
	EventInfo	Initializes a new instance of the EventInfo class.

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Properties

	Name	Description
	Attributes	Gets the attributes for this event.
	DeclaringType	Gets the class that declares this member. (Inherited from MemberInfo.)
	EventHandlerType	Gets the Type object of the underlying event-handler delegate associated with this event.
	IsMulticast	Gets a value that indicates whether the event is multicast.
	IsSpecialName	Gets a value that indicates whether the EventInfo has a name with a special meaning.
	MemberType	Gets a MemberTypes value indicating that this member is an event. (Overrides MemberInfo.MemberType.)
	MetadataToken	Gets a value that identifies a metadata element. (Inherited from MemberInfo.)
	Module	Gets the module in which the type that declares the member represented by the current MemberInfo is defined. (Inherited from MemberInfo.)
	Name	Gets the name of the current member. (Inherited from MemberInfo.)
	ReflectedType	Gets the class object that was used to obtain this instance of MemberInfo. (Inherited from MemberInfo.)

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Methods

	Name	Description
	AddEventHandler	Adds an event handler to an event source.
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetAddMethod()	Returns the method that is used to add an event-handler delegate to the event source.
	GetAddMethod(Boolean)	When overridden in a derived class, returns the method that is used to add an event-handler delegate to the event source, specifying whether to return the method if the current event is non-public.
	GetCustomAttributes(Boolean)	When overridden in a derived class, returns an array of all custom attributes applied to this member. (Inherited from MemberInfo.)
	GetCustomAttributes(Type, Boolean)	When overridden in a derived class, returns an array of custom attributes applied to this member and identified by Type. (Inherited from MemberInfo.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetRaiseMethod()	Returns the method that is called when the event is raised.
	GetRaiseMethod(Boolean)	When overridden in a derived class, returns the method that is called when the event is raised, specifying whether to return non-public methods.
	GetRemoveMethod()	Returns the method that is used to remove an event-handler delegate from the event source.
	GetRemoveMethod(Boolean)	When overridden in a derived class, retrieves the MethodInfo object for removing a method of the event, specifying whether to return non-public methods.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	IsDefined	When overridden in a derived class, indicates whether one or more attributes of the specified type or of its derived types is applied to this member. (Inherited from MemberInfo.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	RemoveEventHandler	Removes an event handler from an event source.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Remarks

Use the EventInfo class to inspect events and to hook up event handlers, as shown in the example code for the AddEventHandler method.

Note:
EventInfo is not intended to be used to raise events. An object raises events as dictated by its internal state.

Calling ICustomAttributeProvider.GetCustomAttributes on EventInfo when the inherit parameter of GetCustomAttributes is true does not walk the type hierarchy. You can use System.Attribute to walk the type hierarchy for custom attributes, but only if all the attributes derive from System.Attribute.

In Silverlight, you cannot inherit from EventInfo.

Examples

The following code gets an EventInfo object for the MouseLeftButtonUp event of a TextBlock control.

Note:
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control.

Imports System.Reflection

Class Example

    Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

        Dim myType As Type = outputBlock.GetType()

        Dim myEvent As EventInfo = myType.GetEvent("MouseLeftButtonUp", _
            BindingFlags.Instance Or BindingFlags.Public)

        If Not (myEvent Is Nothing) Then
            outputBlock.Text &= "Looking for the MouseLeftButtonUp event in the " & _
                myType.FullName & " class." & vbCrLf
            outputBlock.Text &= myEvent.ToString() & vbCrLf
        Else
            outputBlock.Text &= "The MouseLeftButtonUp event is not found in the " & _
                myType.FullName & " class." & vbCrLf
        End If

   End Sub 
End Class 

' This example produces the following output:
'
'Looking for the MouseLeftButtonUp event in the System.Windows.Controls.TextBlock class.
'System.Windows.Input.MouseButtonEventHandler MouseLeftButtonUp

using System.Reflection;
using System;

class Example
{
    public static void Demo(System.Windows.Controls.TextBlock outputBlock)
    {
        Type myType = outputBlock.GetType();

        EventInfo myEvent = myType.GetEvent("MouseLeftButtonUp", 
            BindingFlags.Instance | BindingFlags.Public);

        if (myEvent != null)
        {
            outputBlock.Text += "Looking for the MouseLeftButtonUp event in the " +
                myType.FullName + " class.\n";
            outputBlock.Text += myEvent.ToString() + "\n";
        }
        else
        {
            outputBlock.Text += "The MouseLeftButtonUp event is not found in the " +
                myType.FullName + " class.\r\n";
        }
    }
}

/* This example produces the following output:

Looking for the MouseLeftButtonUp event in the System.Windows.Controls.TextBlock class.
System.Windows.Input.MouseButtonEventHandler MouseLeftButtonUp
 */

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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