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Using a Custom Registration Attribute to Register an Extension

In certain cases you may need to create a new registration attribute for your extension. You can use registration attributes to add new registry keys or to add new values to existing keys. The new attribute must derive from RegistrationAttribute, and it must override the Register and Unregister methods.

Creating a Custom Attribute

The following code shows how to create a new registration attribute.

[AttributeUsage(AttributeTargets.Class, Inherited = true, AllowMultiple = false)]
    public class CustomRegistrationAttribute : RegistrationAttribute
    {
    }

The AttributeUsageAttribute is used on attribute classes to specify the program element (class, method, etc.) to which the attribute pertains, whether it can be used more than once, and whether it can be inherited.

Creating a Registry Key

In the following code, the custom attribute creates a Custom subkey under the key for the VSPackage that is being registered.

public override void Register(RegistrationAttribute.RegistrationContext context)
{
    Key packageKey = null;
    try
    { 
        packageKey = context.CreateKey(@"Packages\{" + context.ComponentType.GUID + @"}\Custom");
        packageKey.SetValue("NewCustom", 1);
    }
    finally
    {
        if (packageKey != null)
            packageKey.Close();
    }
}

public override void Unregister(RegistrationContext context)
{
    context.RemoveKey(@"Packages\" + context.ComponentType.GUID + @"}\Custom");
}

Creating a New Value Under an Existing Registry Key

You can add custom values to an existing key. The following code shows how to add a new value to a VSPackage registration key.

public override void Register(RegistrationAttribute.RegistrationContext context)
{
    Key packageKey = null;
    try
    { 
        packageKey = context.CreateKey(@"Packages\{" + context.ComponentType.GUID + "}");
        packageKey.SetValue("NewCustom", 1);
    }
    finally
    {
        if (packageKey != null)
            packageKey.Close();
                }
}

public override void Unregister(RegistrationContext context)
{
    context.RemoveValue(@"Packages\" + context.ComponentType.GUID, "NewCustom");
}