Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All
Expand Minimize

OpenReadCompletedEventHandler Delegate

Note: This delegate is new in the .NET Framework version 2.0.

Represents the method that will handle the OpenReadCompleted event of a WebClient.

Namespace: System.Net
Assembly: System (in system.dll)

'Declaration
Public Delegate Sub OpenReadCompletedEventHandler ( _
	sender As Object, _
	e As OpenReadCompletedEventArgs _
)
'Usage
Dim instance As New OpenReadCompletedEventHandler(AddressOf HandlerMethod)
/** @delegate */
public delegate void OpenReadCompletedEventHandler (
	Object sender, 
	OpenReadCompletedEventArgs e
)
JScript supports the use of delegates, but not the declaration of new ones.

Parameters

sender

The source of the event.

e

A OpenReadCompletedEventArgs containing event data.

When you create a OpenReadCompletedEventHandler 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. The event handler is called whenever the event occurs, unless you remove the delegate.

The following code example demonstrates downloading a resource for reading.

Public Shared Sub OpenResourceForReading2(ByVal address As String)

    Dim client As WebClient = New WebClient()
    AddHandler client.OpenReadCompleted, AddressOf OpenReadCallback2
                Dim uri as Uri = New Uri(address)
    client.OpenReadAsync(uri)                        
End Sub


The following method is called when the download completes.

Public Shared Sub OpenReadCallback2(ByVal sender As Object, ByVal e As OpenReadCompletedEventArgs)

    Dim reply As Stream = Nothing
    Dim s As StreamReader = Nothing

    Try

        reply = CType(e.Result, Stream)
        s = New StreamReader(reply)
        Console.WriteLine(s.ReadToEnd())
    Finally

        If Not s Is Nothing Then

            s.Close()
        End If

        If Not reply Is Nothing Then

            reply.Close()
        End If
    End Try
End Sub


Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

Community Additions

ADD
Show:
© 2015 Microsoft