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How To: Get automation working properly on data bound WPF list or combo box

  • Artigo

WPF makes it really easy to data bind properties of a control including the children collection of ItemsControl like ListBox, ComboBox, TreeView etc.  For example, for a list box, the user can easily bind the ItemsSource property.

When an ItemsControl is bound to a data source, the accessibility implementation of WPF uses the ToString() method to get the value of each item in the ItemsControl. If the data source is XML (or even if it is .NET class without proper ToString() method), this value is simply the string "System.Xml.XmlElement" (or similar format representing the class type) for all the items.

This means an automation tool cannot get an meaningful property for these items to search. If the automation tool records Name=System.Xml.XmlElement as the search criteria, then it will always playback the action on the first item irrespective of the which item the action was performed.  (For that matter, even the accessibility applications like Narrator will not give any meaningful property.)

The Coded UI Test recorder recognizes this problem and gives following error -

Last action on list item was not recorded because the control does not have any good identification property.

To fix the problem, you can do one of the two things in your product code -

  1. If the data binding is to .NET object(s) and you own the code for those .NET class(es) too, override the ToString() method to provide meaningful value.  This issue stems from the fact that the default ToString() of the System.Object simply returns the type of object as string like System.Xml.XmlElement.
  2. The other alternative is to bind the AutomationProperties.Name property of list item properly.

For example, adding the following code in bold corrects the problem for this List -

   <ListBox Name="GoodList" Grid.Column="1" Grid.Row="1"
           ItemsSource="{Binding Source={StaticResource Oscar2010},
                                 XPath=BestPictureNomination}">
       < ListBox.ItemContainerStyle ><br>          <Style ><br>              <Setter Property ="AutomationProperties.Name"                      Value="{Binding XPath
 =.}"/><br>          </Style ><br>      </ListBox.ItemContainerStyle > 
  </ListBox>

A complete sample XAML file with one bad list and one good list is here.

MainWindow.xaml

Comments

  • Anonymous
    May 26, 2010
    How do I add the property "AutomationProperties.Name" a) to a Window via XAML? b) to a Window programmatically?

  • Anonymous
    May 27, 2010
    Can you please also provide an example for a grid control? I want to read the value from cell (3, 4). Thanks.

  • Anonymous
    June 09, 2010
    Can you please provide a full example with a grid and access one cell with Coded UI Test and upload the Visual Studio solution file. I am having a real hard time figuring out how to do that. Thank you very much.

  • Anonymous
    July 12, 2010
    Sorry for late reply.  For some reason, my blog settings got messed up and I had trouble login in.  In general, the Coded UI Test forum (social.msdn.microsoft.com/.../threads) is better place to post your questions as that is monitored by many folks & you will get faster response. Are you still struggling here?  If so, I suggest putting a post on the above forum and someone from the team will help you. Thanks, Gautam

  • Anonymous
    July 19, 2010
    I managed to get it working in the meantime. Thanks for your reply.

  • Anonymous
    September 23, 2010
    How do I add the property "AutomationProperties.Name" a) to a Window via XAML? b) to a Window programmatically? c) to a List Control ?

  • Anonymous
    September 23, 2010
    @Mihir - You can set it like any other properties.  Not sure I understand your question.

  • Anonymous
    May 23, 2011
    Not able to identify ItemsControl. I have one custom control called Custom1 and in that using ItemsControl. CUIT is able to identify Custom1 but not able to identify ItemsControl. I have downloaded SPOON tool and checked that ItemsControl is child of Custom1 but still CUIT is not getting it. Can you please help me on this?

  • Anonymous
    May 23, 2011
    Please post it on social.msdn.microsoft.com/.../threads and someone from the community will help you. Thanks.