Sharing in a Windows 8 App (Part 2)

In Part 1 of this blog, we explained that Sharing is a unique feature in Windows 8, and that it is a key differentiator from the iPAD.  Your app can declare that it is able to share data, or receive shared data, or both.  We introduced the DataTransferManager, which we will need to tell Windows that your app wants to share data.  We built a simple XAML design surface with sample text to share.   And we implemented the DataRequested event handler in the App.xaml code.  Here in Part 2 we complete the rest of the code.

What we do now is dereference the page that is active.  We do this using an interface, which we will define as follows:

We will write the new GetCurrentPage method as follows:

Now we create a page that implements the sharing interface.  This will be the page that produces the data to share.  The code in the page would look like below:

The only code we added were the using statement and the implementation of the GetSharedData method.  We’ve got all the code we need.  Now when we run this, we will see the following result:

Now we can bring up the charms by hovering over the lower right corner of the screen.

When we click on the Share charm, we see a list on the right side like the one below.

This list simply identifies all of the Windows 8 applications that understand how to share the data type that you have declared.

When you select one of these applications, its corresponding dialog will appear.  You will need to perform some action to complete the task of sharing the text data.  If you chose the Mail application, you can expect something like the following in your mailbox.

 

And there you have it.  We have built a Windows 8 application that is capable of sharing text data to other Windows 8 applications that understand how to share text data.  We can use the very similar logic to share other data types, such as bitmaps and HTML files.  The DataTransferManager is the key.

Sharing in a Windows 8 App (Part 1)

Sharing is a unique feature in Windows 8.  It is a key differentiator from the iPAD.  Windows 8 Apps declare themselves as one of the following:

a)      Able to share data,

b)      Able to receive shared data, or

c)       Both

Most of the time, your Windows 8 Apps will be sharing simple data.  These data types include:

a)      Plain text

b)      RTF

c)       HTML

d)      Bitmaps

e)      Files

f)       URIs

The general idea here is that you don’t declare a format.  Your app just states that it is able to share plain text, or that it is able to share bitmaps, etc, and you allow the target apps to make sense of the data.  There is no strict sense of contracts, the way that an Interface might enforce one.  All that your app is declaring is that it is able to share data, and not that it can perform a certain task.

In order to handle outbound sharing, you will need to use the DataTransferManager to tell Windows that your app wants to be asked for shared data.  When the user selects the Share charm, your app will be called, and it will have the opportunity then to provide or share data.

The Request Handler is registered globally, and the first thing you would need to do is to dereference the current page.  We will do this using an interface.  When sharing its data, your app will first need to provide metadata about the data that it is sharing, including the title and description of the data, before providing the actual data.

For this demo, we will be sharing some basic text.    What I have done below is create a simple XAML design surface with a TextBlock and a TextBox with some sample text in it.  The user will be able to enter any test they want, bring up the Share charm, say that they wish to share the text, and that text will be shared by any application that understands text.

The first thing we have to do is go into the App.xaml code and register the handler.  In the OnLaunched event  handler, at the very end,  we write the following line of code:

We would write the method stub for this new method as follows:

We implement the new DataRequested event handler as follows:

So far, we have discussed what Sharing in a Windows 8 app means.  We introduced the DataTransferManager, which we will need to tell Windows that your app wants to share data.  We built a simple XAML design surface with sample text to share.   And we implemented the DataRequested event handler in the App.xaml code.  In Part 2 we complete the rest of the code.