Supporting the “new” Operator in VSTA Add-Ins

It is possible to support the “new” operator in VSTA add-ins.  Integration styles which do not use a full proxy, such as NoRuntime and ProxyShim, can easily support this feature.  All that is required is public constructor methods in the host application.  In the ShapeAppDyanmicProgrammingModelCSharp sample an additional code change is required in order to ensure all host items created in the add-in using the “new” operator are hooked-up prior to building (for more information on this please see the blog ShapeAppDynamicProgrammingModelCSharp_ProxyShim Sample).  This is possible because these styles of integration do not use a full proxy, which generally cannot support the new operator and must instead use factory methods.  One exception to this rule is for structs and custom exceptions in VSTA v 2 add-ins.  Because structs and custom exceptions are reimplemented in the proxy their public constructors are available for VSTA v 2 add-ins.  For more information on the different styles of integration, please see the blog Integration Styles and the Benefits: SDK, NoRuntime, and ProxyShim.

Below are code samples which show how to create a new Drawing object for the ShapeAppCSharp samples in the SDK, NoRuntime, and ProxyShim style integrations:

NoRuntime and ProxyShim: 

Both integration styles can use public constructor methods, in this example a public constructor for the Drawing class was added by changing the existing private constructor to public.  Note that the factory method may still be used.
//create a new Drawing using a public constructor

Drawing d = new Drawing(this.Application, "Drawing4");

'create a new drawing using a public constructor

Dim d As Drawing = New Drawing(Me.Application, "Drawing4")

SDK Factory Method: 

This code utilizes the factory method Application.NewDrawing (this is from the VSTA v 1 samples but applies to VSTA v 2 as well).

//create a new drawing using the factory method

Drawing d = this.NewDrawing();

'create a new drawing using the factory method

Dim d As Drawing = Me.NewDrawing()

SDK Structs and Custom Exceptions (VSTA v 2 only):

Because structs and custom exceptions are reimplemented in the proxy layer, their public constructors are available.

//factory methods, these are static methods in the application class

Color cFM = Microsoft.VisualStudio.Tools.Applications.Samples.ShapeApp.

    Application.CreateColor(System.Drawing.Color.Green.ToArgb());

Point pFM = Microsoft.VisualStudio.Tools.Applications.Samples.ShapeApp.

    Application.CreatePoint(25, 25);

Size sFM = Microsoft.VisualStudio.Tools.Applications.Samples.ShapeApp.

    Application.CreateSize(25, 25);           

//public constructos for structs and custom exceptions

Color cPC = new Color(System.Drawing.Color.Green);

Point pPC = new Point(25,25);

Size sPC = new Size(25, 25);

LocationInvalidException liePC= new LocationInvalidException("invalid location");

SizeInvalidException siePC = new SizeInvalidException("invalid size");

'factory methods, these are static methods in the application class

Dim cFM As Color = Microsoft.VisualStudio.Tools.Applications.Samples.ShapeApp. _

    Application.CreateColor(System.Drawing.Color.Green.ToArgb())

Dim pFM As Point = Microsoft.VisualStudio.Tools.Applications.Samples.ShapeApp. _

    Application.CreatePoint(25, 25)

Dim sFM As Size = Microsoft.VisualStudio.Tools.Applications.Samples.ShapeApp. _

    Application.CreateSize(25, 25)

'public constructos for structs and custom exceptions

Dim cPC As Color = New Color(System.Drawing.Color.Green)

Dim pPC As Point = New Point(25, 25)

Dim sPC As Size = New Size(25, 25)

Dim liePC As LocationInvalidException = New LocationInvalidException("invalid location")

Dim siePC As SizeInvalidException = New SizeInvalidException("invalid size")