DataPackage.SetDataProvider(String, DataProviderHandler) 方法
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
设置委托以处理来自目标应用的请求。
public:
virtual void SetDataProvider(Platform::String ^ formatId, DataProviderHandler ^ delayRenderer) = SetDataProvider;
void SetDataProvider(winrt::hstring const& formatId, DataProviderHandler const& delayRenderer);
public void SetDataProvider(string formatId, DataProviderHandler delayRenderer);
function setDataProvider(formatId, delayRenderer)
Public Sub SetDataProvider (formatId As String, delayRenderer As DataProviderHandler)
参数
- formatId
-
String
Platform::String
winrt::hstring
指定数据的格式。 建议使用 StandardDataFormats 类设置此值。
- delayRenderer
- DataProviderHandler
负责处理来自目标应用的请求的委托。
示例
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using Windows.Storage;
using Windows.Storage.Pickers;
using Windows.Storage.Streams;
using Windows.UI.Xaml.Media.Imaging;
using Windows.Storage;
using Windows.Storage.Pickers;
using Windows.Storage.Streams;
using Windows.UI.Xaml.Media.Imaging;
using Windows.ApplicationModel.DataTransfer;
using Windows.Graphics.Imaging;
namespace ShareMainBetaCS
{
public sealed partial class ShareFiles : Page
{
private StorageFile imageFile = null;
private RandomAccessStreamReference imageStreamRef = null;
private RandomAccessStreamReference dataPackageThumbnail = null;
private IRandomAccessStream imageStream = null;
public ShareFiles()
{
this.InitializeComponent();
pickImageButton.Click += new RoutedEventHandler(pickImageButton_Click);
this.ShareSourceLoad();
}
async void pickImageButton_Click(object sender, RoutedEventArgs e)
{
FileOpenPicker imagePicker = new FileOpenPicker
{
ViewMode = PickerViewMode.Thumbnail,
SuggestedStartLocation = PickerLocationId.PicturesLibrary,
FileTypeFilter = { ".jpg", ".png", ".bmp", ".gif", ".tif" }
};
this.imageFile = await imagePicker.PickSingleFileAsync();
if (this.imageFile != null)
{
this.imageStreamRef = RandomAccessStreamReference.CreateFromFile(this.imageFile);
this.dataPackageThumbnail = this.imageStreamRef;
this.imageStream = await this.imageFile.OpenAsync(FileAccessMode.Read);
}
}
public void ShareSourceLoad()
{
DataTransferManager datatransferManager;
datatransferManager = DataTransferManager.GetForCurrentView();
datatransferManager.DataRequested += new TypedEventHandler<DataTransferManager, DataRequestedEventArgs>(this.DataRequested);
}
void DataRequested(DataTransferManager sender, DataRequestedEventArgs e)
{
e.Request.Data.Properties.Title = "Hello World!";
e.Request.Data.Properties.Description = "This example shows how to use delayed sharing.";
if (this.dataPackageThumbnail != null)
{
e.Request.Data.Properties.Thumbnail = this.dataPackageThumbnail;
}
e.Request.Data.SetDataProvider(StandardDataFormats.Bitmap,
new DataProviderHandler(this.OnDeferredImageRequestedHandler));
}
async void OnDeferredImageRequestedHandler(DataProviderRequest request)
{
// Here we provide updated Bitmap data using delayed rendering
if (this.imageStream != null)
{
DataProviderDeferral deferral = request.GetDeferral();
try
{
InMemoryRandomAccessStream inMemoryStream = new InMemoryRandomAccessStream();
// Decode the image
BitmapDecoder imageDecoder = await BitmapDecoder.CreateAsync(this.imageStream);
// Re-encode the image at 50% width and height
BitmapEncoder imageEncoder = await BitmapEncoder.CreateForTranscodingAsync(inMemoryStream, imageDecoder);
imageEncoder.BitmapTransform.ScaledWidth = (uint)(imageDecoder.OrientedPixelHeight * 0.5);
imageEncoder.BitmapTransform.ScaledHeight = (uint)(imageDecoder.OrientedPixelHeight * 0.5);
await imageEncoder.FlushAsync();
request.SetData(RandomAccessStreamReference.CreateFromStream(inMemoryStream));
}
catch (Exception ex)
{
// Handle the exception
}
finally
{
deferral.Complete();
}
}
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
}
}
}
注解
如果应用支持特定格式,但在目标应用请求数据之前不希望提供数据,请使用 SetDataProvider 方法。 如果你的应用共享可能需要大量处理时间的内容,我们建议你使用此方法;例如,共享所选的照片、视频或文件。
使用此方法时,需要指定格式和函数。 可以使用 StandardDataFormats 类指定格式,也可以将字符串值用于自定义格式。 函数必须使用 SetData 等方法将数据放入 DataPackage 中。
必须指定要传递给共享目标的 StorageItems 的扩展。
SetDataProvider 方法不同于 DataRequest 类的 GetDeferral 方法。 使用 GetDeferral,源应用可以调用立即将数据放入 DataPackage 对象的函数。 SetDataProvider 方法适用于更复杂的共享操作,其中打包要共享的数据更耗时或资源密集型。