Jeff Lynch [MVP]

public CatalogItemsDataSet GetRootProducts(string CatalogName)

{

    return CommerceContext.Current.CatalogSystem.GetCatalog(CatalogName).GetRootCategory().ChildProducts.DataSet;

}

public CatalogItemsDataSet GetCategoryProducts(string CatalogName, string CategoryName)

{

    return CommerceContext.Current.CatalogSystem.GetCatalog(CatalogName).GetCategory(CategoryName).ChildProducts.DataSet;

}

public CatalogItemsDataSet GetRootCategories(string CatalogName)

{

    return CommerceContext.Current.CatalogSystem.GetCatalog(CatalogName).GetRootCategory().ChildCategories.DataSet;

}

public CatalogItemsDataSet GetSubCategories(string CatalogName, string CategoryName)

{

    return CommerceContext.Current.CatalogSystem.GetCatalog(CatalogName).GetCategory(CategoryName).ChildCategories.DataSet;

}

public CatalogItemsDataSet SearchForProducts(string CatalogName, string SearchPhrase)

{        

    CatalogSearch catalogSearch = CommerceContext.Current.CatalogSystem.GetCatalogSearch();

    catalogSearch.CatalogNames = CatalogName; 

    catalogSearch.SearchOptions.ClassTypes = CatalogClassTypes.ProductClass;

    catalogSearch.FreeTextSearchPhrase = SearchPhrase; 

    return catalogSearch.Search();

} 

As you can see, the CatalogItemsDataSet is pretty versatile and is easily bound to any ASP.NET databound control.