MSDN Magazine - December 2008 - (Page 71)

sort items as rows in the table. From Outlook 2007 onwards, you should use the Table mechanism in preference to the traditional method of working with collections of items. To get a table, you use the same filter string that you would use with the Restrict or Find methods, but you use this with the GetTable method instead. From the code shown in Figure 9, it should be clear that there would be little advantage in using the existing version of the LINQ-to-DASL extensions with an Outlook Table, because you still need to use a query string to get a Table, and Table filtering is done by specifying Table Columns. The LINQ-to-DASL approach in the extensions library can be used for either Outlook 2003 or Outlook 2007, but if you are targeting Outlook 2007 only, the Table approach is likely to offer better performance, especially for large data sets. Example code for this approach is in Figure 9. Figure 10 Outlook Query in Visual Basic Dim source As New ItemsSource(Of MailEx)(folder.Items) Dim builder As New StringBuilder() Dim filteredItems = ( _ From item In source _ Where item.MessageClass.StartsWith("IPM.Note") _ AndAlso item.Subject.StartsWith("RE:") _ AndAlso item.DateReceived >= _ (DateTime.Now.ToUniversalTime() - New TimeSpan(30, 0, 0, 0)) _ Select item).ToList() For Each filteredItem In filteredItems builder.AppendLine(String.Format("{0},{1},{2}", _ filteredItem.Date, filteredItem.DateReceived, filteredItem.Size)) Next MessageBox.Show(builder.ToString()) Figure 11 MailEx for Visual Basic Friend Class MailEx Inherits Mail _ Public ReadOnly Property Size() As Integer Get Return MyBase.Item.Size End Get End Property _ Public Overrides ReadOnly Property MessageClass() As String Get Return MyBase.Item.MessageClass End Get End Property End Class Using the Extensions in Visual Basic The main benefit of the extensions is to provide C# developers with a coding experience that is similar to Visual Basic. That said, some of the extensions—in particular, the LINQ-to-DASL extensions—also bring benefits to developers working in Visual Basic (or indeed any other managed language). For example, it is beneficial in any language to use a strongly typed LINQ query instead of a string-based DASL query. Figure 10 shows a Visual Basic version of the Outlook query operation. Note one of the differences in the way C# and Visual Basic generate expression trees. C# uses the base type—OutlookItem, in our example—which defines a mapped property for MessageClass. On the other hand, Visual Basic uses the most derived type—Mail— which defines an override for MessageClass that is not attributed with a property mapping. For this reason, we have to define another override of MessageClass in our MailEx class (see Figure 11) that is attributed with a property mapping (this is another possible place for improvement in future releases). Wrapping Up Vsto Resources To learn even more about using VSTO to build your own Officebased applications, see these articles from the archives of MSDN Magazine: VSTO 3.0: Developing Office Business Apps with Visual Studio 2008 by Steve Fox In this article, we showed how C# developers can use the Office interop API extensions to streamline Office development. The extensions provide a thin, strongly typed layer over the loosely typed Office object models, which makes your code less error-prone and more robust, and can significantly reduce the cost of testing and maintenance. We also showed how to extend the extensions for custom scenarios and how to use them in Visual Basic.  Andrew whitechApel is a Program Manager in the Visual Studio Business Applications team, responsible for architecting new Office development features in Visual Studio. msdn.microsoft.com/magazine/cc164242 VSTO: Build Office-Based Solutions Using WPF, WCF, and LINQ by Andrew Whitechapel phillip hoff is a Software Development Engineer in the Visual Studio Busi- msdn.microsoft.com/magazine/cc163292 Office Apps: Extend Your VBA Code with VSTO by Paul Stubbs and Kathleen McGrath ness Applications team and is one of the original authors of the Office Interop API Extensions library. He is currently working on SharePoint tool integration with Visual Studio. VlAdimir morozoV is a developer in the Visual Studio Business Applications team. He worked together with Phillip Hoff on envisioning and creation of the Office Interop API Extensions library. He is currently working on SharePoint tooling for Visual Studio. msdn.microsoft.com/magazine/cc163373 msdnmagazine.com December 2008 71 http://schemas.microsoft.com/mapi/proptag/0x0E080003 http://schemas.microsoft.com/mapi/proptag/0x001a001e http://msdn.microsoft.com/magazine/cc164242 http://msdn.microsoft.com/magazine/cc163292 http://msdn.microsoft.com/magazine/cc163373 http://www.msdnmagazine.com

Table of Contents Feed for the Digital Edition of MSDN Magazine - December 2008

MSDN Magazine - December 2008 Contents Toolbox CLR Inside Out Advanced Basics Cutting Edge Patterns In Practice Team System Real-World WF Visual Studio OBA Tools SOA Data Access Geneva Framework Test Run Foundations Windows With C++ Going Places End Bracket

MSDN Magazine - December 2008

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