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Building CommonSnappableTypes.dll

The first order of business is to create an assembly that contains the types that a given snap-in must

leverage to be plugged into the expandable Windows Forms application. The CommonSnappable-

Types Class Library project defines two types:

namespace CommonSnappableTypes

{

public interface IAppFunctionality

{

void DoIt();

}

[AttributeUsage(AttributeTargets.Class)]

public sealed class CompanyInfoAttribute : System.Attribute

{

private string companyName;

private string companyUrl;

public CompanyInfoAttribute(){}

public string Name

{

get { return companyName; }

set { companyName = value; }

}

public string Url

{

get { return companyUrl; }

set { companyUrl = value; }

}

}

}

The IAppFunctionality interface provides a polymorphic interface for all snap-ins that can be

consumed by the extendable Windows Forms application. Given that this example is purely illustra-

tive, you supply a single method named DoIt(). A more realistic interface (or a set of interfaces)

might allow the object to generate scripting code, render an image onto the application’s toolbox, or

integrate into the main menu of the hosting application.

The CompanyInfoAttribute type is a custom attribute that will be applied on any class type

that wishes to be snapped in to the container. As you can tell by the definition of this class,

[CompanyInfo] allows the developer of the snap-in to provide some basic details about the compo-

nent’s point of origin.

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