.NET Framework 4.6 and 4.5
Provides data for the DownloadDataCompleted event.
Assembly: System (in System.dll)
Thetype exposes the following members.
|Cancelled||Gets a value indicating whether an asynchronous operation has been canceled. (Inherited from AsyncCompletedEventArgs.)|
|Error||Gets a value indicating which error occurred during an asynchronous operation. (Inherited from AsyncCompletedEventArgs.)|
|Result||Gets the data that is downloaded by a DownloadDataAsync method.|
|UserState||Gets the unique identifier for the asynchronous task. (Inherited from AsyncCompletedEventArgs.)|
|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 it is reclaimed by garbage collection. (Inherited from Object.)|
|GetHashCode||Serves as the default hash function. (Inherited from Object.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|MemberwiseClone||Creates a shallow copy of the current Object. (Inherited from Object.)|
|RaiseExceptionIfNecessary||Raises a user-supplied exception if an asynchronous operation failed. (Inherited from AsyncCompletedEventArgs.)|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
The following code example demonstrates downloading a user-specified resource.
' Sample call : DownLoadDataInBackground ("http:' www.contoso.com/GameScores.html") Public Shared Sub DownloadDataInBackground(ByVal address As String) Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(False) Dim client As WebClient = New WebClient() ' Specify that the DownloadDataCallback method gets called ' when the download completes. AddHandler client.DownloadDataCompleted, AddressOf DownloadDataCallback Dim uri as Uri = New Uri(address) client.DownloadDataAsync(uri, waiter) ' Block the main application thread. Real applications ' can perform other tasks while waiting for the download to complete. waiter.WaitOne() End Sub
The following method is called when the download completes.
Private Shared Sub DownloadDataCallback(ByVal sender As Object, ByVal e As DownloadDataCompletedEventArgs) Dim waiter As System.Threading.AutoResetEvent = CType(e.UserState, System.Threading.AutoResetEvent) Try ' If the request was not canceled and did not throw ' an exception, display the resource. If e.Cancelled = False AndAlso e.Error Is Nothing Then Dim data() As Byte = CType(e.Result, Byte()) Dim textData As String = System.Text.Encoding.UTF8.GetString(data) Console.WriteLine(textData) End If Finally ' Let the main application thread resume. waiter.Set() End Try End Sub