Share content from your Windows app

The Windows Share contract lets users quickly share content—such as text, links, photos, and videos—from your app to other apps. For example, a user might want to share a webpage with their friends using a social networking app, or save a link in a notes app to refer to later.

This article explains how to implement the source side of the Share contract: the code that prepares content and opens the Windows Share Sheet from your app. For information on receiving shared content, see Receive shared data in your Windows app.

The Windows.ApplicationModel.DataTransfer APIs used in this article work for apps that have package identity, including UWP apps and packaged WinUI 3 desktop apps. Unpackaged Win32 apps can participate by granting package identity and then using IDataTransferManagerInterop.

Set up an event handler

Register a DataRequested event handler on your DataTransferManager instance. This event fires when the user invokes Share—for example, when they tap a Share button in your app, or when your app determines there is content ready to share.

For WinUI 3 desktop apps, obtain the DataTransferManager for your window using IDataTransferManagerInterop, as described in Display WinRT UI objects that depend on CoreWindow.

Provide content in the DataRequested handler

When a DataRequested event occurs, your app receives a DataRequest object containing a DataPackage that you populate with the content to share. You must set a title and at least one data format. A description is optional but recommended.

private void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
    DataRequest request = args.Request;
    request.Data.Properties.Title = "Contoso article";
    request.Data.Properties.Description = "An interesting article from Contoso.";
    request.Data.SetText("Read this article at Contoso.com.");
    request.Data.SetWebLink(new Uri("https://contoso.com/articles/1234"));
}

Choose data formats

DataPackage supports multiple built-in data formats. You can provide more than one format in the same package—the receiving app uses whichever format it supports best.

Set properties

DataPackagePropertySet lets you attach additional metadata to the shared content. Adding a thumbnail gives the share sheet a richer visual preview. For more information, see DataPackagePropertySet.

private void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
    DataRequest request = args.Request; // The DataRequested event provides the request via args.Request.
    request.Data.Properties.Title = "Sunset photo";
    request.Data.Properties.Description = "Taken at Lake Tahoe.";
    // Providing a thumbnail is optional but improves the share sheet preview.
    // request.Data.Properties.Thumbnail = RandomAccessStreamReference.CreateFromFile(thumbnailFile);
}

Launch the share UI

After registering for the DataRequested event, open the Windows Share Sheet when the user invokes Share. For WinUI 3 desktop apps, call ShowShareUIForWindow on the IDataTransferManagerInterop interface, passing your window's HWND. For code examples, see Display WinRT UI objects that depend on CoreWindow.

Handle errors

If your app can't provide sharable content—for example, because the user hasn't selected anything—call FailWithDisplayText to show an informative message in the share UI:

private void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
    if (string.IsNullOrEmpty(selectedText))
    {
        args.Request.FailWithDisplayText("Select some text in the app before sharing.");
        return;
    }

    args.Request.Data.Properties.Title = "Selected text";
    args.Request.Data.SetText(selectedText);
}

Delay share with delegates

If producing the share data is resource-intensive—for example, encoding a large image at multiple resolutions—use a delegate so the data is produced only when the receiving app requests it. This avoids unnecessary work when the user hasn't chosen a target yet.

private void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
    args.Request.Data.Properties.Title = "High-res photo";
    args.Request.Data.SetDataProvider(StandardDataFormats.Bitmap, OnDeferredImageRequested);
}

// Note: DataProviderHandler requires async void. The try/finally ensures the
// deferral completes even if an exception occurs.
private async void OnDeferredImageRequested(DataProviderRequest request)
{
    DataProviderDeferral deferral = request.GetDeferral();
    try
    {
        if (this.imageStream == null)
        {
            return;
        }

        InMemoryRandomAccessStream inMemoryStream = new InMemoryRandomAccessStream();

        // Decode the source image and re-encode at 50% size.
        BitmapDecoder imageDecoder = await BitmapDecoder.CreateAsync(this.imageStream);
        BitmapEncoder imageEncoder = await BitmapEncoder.CreateForTranscodingAsync(
            inMemoryStream, imageDecoder);

        imageEncoder.BitmapTransform.ScaledWidth =
            (uint)(imageDecoder.OrientedPixelWidth * 0.5);
        imageEncoder.BitmapTransform.ScaledHeight =
            (uint)(imageDecoder.OrientedPixelHeight * 0.5);
        await imageEncoder.FlushAsync();

        request.SetData(RandomAccessStreamReference.CreateFromStream(inMemoryStream));
    }
    finally
    {
        deferral.Complete();
    }
}

See also

• Receive shared data in your Windows app
• Integrate packaged apps with Windows Share
• Integrate unpackaged apps with Windows Share
• Display WinRT UI objects that depend on CoreWindow
• IDataTransferManagerInterop
• DataTransferManager
• DataPackage
• DataRequest
• FailWithDisplayText
• WPF Sharing content source app sample