public event EventHandler<SharePointClientDownloadCompletedEventArgs> DownloadCompleted
The event handler receives an argument of type SharePointClientDownloadCompletedEventArgs containing data related to this event. The following SharePointClientDownloadCompletedEventArgs properties provide information specific to this event.
Property | Description |
---|---|
Cancelled (Inherited from System.ComponentModel.AsyncCompletedEventArgs) | Gets a value indicating whether an asynchronous operation has been canceled. |
DestinationData | Gets the download destination stream data. |
DestinationFileName | Gets the download operation destination file name. |
Error (Inherited from System.ComponentModel.AsyncCompletedEventArgs) | Gets a value indicating which error occurred during an asynchronous operation. |
SourceUri | Gets the URI of the source item being downloaded. |
UserState (Inherited from System.ComponentModel.AsyncCompletedEventArgs) | Gets the unique identifier for the asynchronous task. |
The SharePointClient class supports downloading an item asynchronously using the DownloadFileAsync and GetDownloadStreamAsync methods. When you call these methods, control returns instantly to your program and the DownloadCompleted event occurs when the download operation is completed (whether or not the operation was successful).
Note that the SharePointClientDownloadCompletedEventArgs derives from the standard .NET System.ComponentModel.AsyncCompletedEventArgs class and adds properties specified to SharePoint download support.
When the download operation is completed, the DownloadCompleted event will receive a SharePointClientDownloadCompletedEventArgs object containing the foolowing information about the operation:
Property | Value |
---|---|
SourceUri |
The source URI. This is the same value as the sourceUri parameter passed to the DownloadFileAsync or GetDownloadStreamAsync method. |
DestinationFileName |
The destination file name. This is the same value as the destinationFileName parameter passed to DownloadFileAsync if this method was called to initiate the download. If GetDownloadStreamAsync was called to initiate the download, then the value of this property is null (Nothing in Visual Basic) |
DestinationData |
A SharePointClientDownloadData object that contains the download stream information if GetDownloadStreamAsync was called to initiate the download. If DownloadFileAsync was used to initiate the download, then the value of this property will be null (Nothing in Visual Basic) Note that you are responsible for calling System.IDisposable.Dispose on DestinationData if you subscribe to the DownloadCompleted event. |
System.ComponentModel.AsyncCompletedEventArgs.Error |
Gets a value that indicates which error occurred during the asynchronous download operation. If an exception is raised during the asynchronous download operation, the class assigns the exception to the System.ComponentModel.AsyncCompletedEventArgs.Error property. The client application's event-handler delegate should check the System.ComponentModel.AsyncCompletedEventArgs.Error property before accessing any properties in the SharePointClientDownloadCompletedEventArgs class. The value of the System.ComponentModel.AsyncCompletedEventArgs.Error property is null (Nothing in Visual Basic) if the operation was canceled. |
System.ComponentModel.AsyncCompletedEventArgs.UserState |
Gets the unique identifier for the asynchronous download operation. The value of this property is the same as the userState parameter passed to the DownloadFileAsync or GetDownloadStreamAsync method. |
System.ComponentModel.AsyncCompletedEventArgs.Cancelled |
true if the asynchronous download operation has been canceled; otherwise, false. This class does not change the value of this property from the default value of false |
using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing;
using Leadtools.ImageProcessing.Color;
using Leadtools.SharePoint.Client;
public void SharePointClientDownloadFileAsyncExample()
{
// Replace SHAREPOINT_SITE_URI with a valid URL to a SharePoint site, for example
// http://SiteCollection/MySite
Uri siteUri = new Uri(SHAREPOINT_SITE_URI);
// Replace SHAREPOINT_FOLDER_NAME with a valid folder on the site above, for example
// "Documents" or "Documents\Sub Documents"
string folderName = SHAREPOINT_FOLDER_NAME;
// Replace SHAREPOINT_DOCUMENT_NAME with a valid document on the folder above, for example
// MyDocument.tif
string documentName = SHAREPOINT_DOCUMENT_NAME;
// Build the full URL to the document are we going to download
UriBuilder builder = new UriBuilder(siteUri);
builder.Path = Path.Combine(builder.Path, folderName);
builder.Path = Path.Combine(builder.Path, documentName);
Uri sourceDocumentUri = builder.Uri;
SharePointClient spClient = new SharePointClient();
// Optional: Set the credentials:
spClient.Credentials = new NetworkCredential(USER_NAME, PASSWORD, DOMAIN);
string tempFileName = Path.GetTempFileName();
// If this is a console application demo, we might exit the program before the operation completes,
// so use a wait handle to not exit this method till the opreation completes
AutoResetEvent wait = new AutoResetEvent(false);
// Download the SharePoint item to the temporary file asynchronously
spClient.DownloadCompleted += new EventHandler<SharePointClientDownloadCompletedEventArgs>(MyDownloadFileAsyncCompleted);
spClient.DownloadFileAsync(sourceDocumentUri, tempFileName, wait);
// Wait till the operation completes
wait.WaitOne();
wait.Close();
// Delete the temporary file we created
File.Delete(tempFileName);
}
private static void MyDownloadFileAsyncCompleted(object sender, SharePointClientDownloadCompletedEventArgs e)
{
// Remove our handler
SharePointClient spClient = sender as SharePointClient;
spClient.DownloadCompleted -= new EventHandler<SharePointClientDownloadCompletedEventArgs>(MyDownloadFileAsyncCompleted);
if (e.Error == null && !e.Cancelled)
{
// All is OK, use RasterCodecs to get its info
using (RasterCodecs codecs = new RasterCodecs())
{
using (CodecsImageInfo imageInfo = codecs.GetInformation(e.DestinationFileName, true))
{
// Show the image info
Console.WriteLine("URL: {0}", e.SourceUri);
Console.WriteLine("Pages: {0}", imageInfo.TotalPages);
Console.WriteLine("Size: {0} by {1} pixels", imageInfo.Width, imageInfo.Height);
Console.WriteLine("Resolution: {0} by {1} dpi", imageInfo.XResolution, imageInfo.YResolution);
Console.WriteLine("Bits/Pixel: {0}", imageInfo.BitsPerPixel);
}
}
}
else
{
// Some error occured
if (e.Error != null)
Console.WriteLine(e.Error.Message);
else
Console.WriteLine("User cancelled");
}
// Tell whoever is listening that we are done
EventWaitHandle wait = e.UserState as EventWaitHandle;
wait.Set();
}