Instance Binding Class

public class InstanceBinding : ElementBinding

public bool SetNewParameterToInstanceWall(UIApplication app, DefinitionFile myDefinitionFile)
{
    // create a new group in the shared parameters file
    DefinitionGroups myGroups = myDefinitionFile.Groups;
    DefinitionGroup myGroup = myGroups.Create("MyParameters1");

    // create an instance definition in definition group MyParameters
    ExternalDefinitionCreationOptions option = new ExternalDefinitionCreationOptions("Instance_ProductDate", SpecTypeId.String.Text);
    // Don't let the user modify the value, only the API
    option.UserModifiable = false;
    // Set tooltip
    option.Description = "Wall product date";
    Definition myDefinition_ProductDate = myGroup.Definitions.Create(option);

    // create a category set and insert category of wall to it
    CategorySet myCategories = app.Application.Create.NewCategorySet();
    // use BuiltInCategory to get category of wall
    Category myCategory = Category.GetCategory(app.ActiveUIDocument.Document, BuiltInCategory.OST_Walls);


    myCategories.Insert(myCategory);

    //Create an instance of InstanceBinding
    InstanceBinding instanceBinding = app.Application.Create.NewInstanceBinding(myCategories);

    // Get the BingdingMap of current document.
    BindingMap bindingMap = app.ActiveUIDocument.Document.ParameterBindings;

    // Bind the definitions to the document
    bool instanceBindOK = bindingMap.Insert(myDefinition_ProductDate,
                                    instanceBinding, GroupTypeId.Text);
    return instanceBindOK;
}