MSDN Magazine - July 2008 - (Page 17)

MUEEz SIddIqUI CLR InsIde Out Extend Windows Forms Apps Using System.AddIn Did you know that you can now make Winwork impose constraints on the object model. dows® Forms applications extensible by using In general, the object model should define all the new Microsoft® .NET add-in framework the types that the add-in will use that aren’t (System.AddIn)? In this column I will modify built-in to the .NET Framework; in other the ShapeApp drawing application to expose words, the view assembly should not referits object model through the add-in frameence any assemblies other than the .NET work. This will allow me to create add-ins that Framework assemblies. MarshalByRefObject automatically perform tasks on the host applitypes are explicitly disallowed. For a more decation (automation add-ins). Also, I’ll discuss tailed breakdown of the allowable types, see the kinds of problems commonly encountered the blog post on contracts at go.microsoft.com/ fwlink/?LinkId=117520. in this scenario and present solutions. If you need background information on Figure 2 lists the types in the ShapeApp’s the add-in framework before you get started, object model. All of the classes you see there a good place to begin is the resources page on exist internally in the host application. I will be the CLR Add-In Team Blog at go.microsoft.com/ exposing them through the pipeline later. fwlink/?LinkId=117519. You might also consider The next step is to add a way for the host to reading the previous CLR Inside Out columns Figure 1 Screenshot of a ShapeApp discover and activate add-ins. For this I use a Drawing on the add-in framework. simple add-in manager on the host. This inShapeApp is a drawing application that lets you make drawings cludes both a static class, AddInManager, that loads and keeps track using basic shapes. You can insert new shapes, move them around, of add-ins and a form that lets the user manage add-ins. The form change their color and size, and so on. It allows you to save draw- is activated through a menu item on the host, requiring minimal ings to files and to open multiple drawings in tabs. A simple draw- changes to the host. The form is shown in Figure 3. ing created in ShapeApp can be seen in Figure 1. The add-in manager code is very simple. Here are the three lines ShapeApp was developed by the Visual Studio® Tools for Appli- required to find available add-ins: // update the add-in store to include add-ins located in the cations (VSTA) team as a sample, which lets you embed the Visu// current program folder al Studio IDE into your application. The IDE can then be used to string[] warnings = AddInStore.Update(PipelineStoreLocation.ApplicationBase); // get the view type defined in the host views assembly write extensions for the application. They have provided versions System.Type hostViewOfAddIn = typeof(ShapeAppHostViews.IShapeAddIn); of the application with and without their extensibility code. In this // find all add-ins that implement the view ICollection addIns = AddInStore.FindAddIns(hostViewOfAddIn, sample, I start from the base version and adapt it to work with the PipelineStoreLocation.ApplicationBase); add-in framework. Adapting the Host Figure 2 ShapeApp Types Type ShapeApplication Drawing Shape DrawingCollection ShapeCollection EventArgs-related types In this section I’ll adapt the application to expose its object model, similar to the Document Object Model (DOM) in HTML. This will allow me to create add-ins that automate tasks in the application. The first step in adapting the host is to define an object model that the host will expose (note that I don’t need to write any code yet). The isolation and versioning capabilities of the add-in frameSend your questions and comments to clrinout@microsoft.com. Code download available at msdn.microsoft.com/magazine/cc135911. Description The main application object. An object that represents a drawing in the application. An object that represents a shape in a drawing. A collection of drawing objects. A collection of shape objects. Several types derived from System.EventArgs, used for custom event arguments. July 2008 17 http://go.microsoft.com/fwlink/?LinkId=117520 http://go.microsoft.com/fwlink/?LinkId=117520 http://go.microsoft.com/fwlink/?LinkId=117519 http://go.microsoft.com/fwlink/?LinkId=117519 http://msdn.microsoft.com/magazine/cc135911

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

MSDN Magazine - July 2008 Contents Toolbox CLR Inside Out Flex Your Data Data Points Advanced Basics Office Space Cutting Edge Data Services ADO.NET Data and WPF Transactions WCF P2P Test Run Security Briefs Foundations .NET Matters {End Bracket}

MSDN Magazine - July 2008

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