What is the best way to check if the Item is being inherited from a template?

Question

I am using Sitecore 10.1 and I am upgrading my code from the Sitecore 8.2 solutions.

I want to know the best practice to check if the Item is being inherited from a template? The requirement is to use a method (maybe OOTB) that should not reduce the performance. Please suggest.

Answer 1

There is an OOTB call that handles this now.

protected virtual bool InheritsTemplate(Item candidate, string templateIdentifier)
{
    if (candidate == null || string.IsNullOrEmpty(templateIdentifier))
        return false;

    var t = TemplateManager.GetTemplate(candidate);
    var y = TemplateManager.GetTemplate(templateIdentifier, candidate.Database);

    if (y == null)
        throw new Exception($"Invalid Template Identifier: \'{templateIdentifier}\'");

    return t.InheritsFrom(y.ID);
}

The important parts of this code being:

// Get the template of the Item you want to check
var t = TemplateManager.GetTemplate(candidate);

// Get the template you want to check for
var y = TemplateManager.GetTemplate(templateIdentifier, candidate.Database);

// then use the OOTB call
t.InheritsFrom(y.ID)

templateIdentifier could be anything you can normally send to Sitecore; e.g. an ID or a template path user defined/common folder or whatever.

Answer 2

I just found a blog which might be helpful. Please check this https://kylekingsbury.com/a-faster-isderived-extension-method/

Here is quick code and info I captured from this blog. We can find the updates to the IsDerived extension methods that reduced the time taken.

public static class ItemExtensions
{
    /// <summary>
    /// Determine if the Item inherits a specific template, by ID
    /// </summary>
    /// <param name="item">The item</param>
    /// <param name="templateId">The template id</param>
    /// <returns><c>True</c> if the item inherits from <paramref name="templateId"/></returns>
    public static bool IsDerived(this Item item, ID templateId)
    {
        if (item == null)
        {
            return false;
        }

        return !templateId.IsNull && item.IsDerived(item.Database.GetItem(templateId, item.Language));
    }

    /// <summary>
    /// Determine if the Item inherits a specific template, by TemplateItem
    /// </summary>
    /// <param name="item">The item</param>
    /// <param name="inheritedTemplateItem">the templateItem</param>
    /// <returns><c>True</c> if the item inherits from <paramref name="inheritedTemplateItem"/></returns>
    public static bool IsDerived(this Item item, Item inheritedTemplateItem)
    {
        if (item == null
            || inheritedTemplateItem == null)
        {
            return false;
        }

        var itemTemplate = TemplateManager.GetTemplate(item);

        return itemTemplate != null && (itemTemplate.ID == inheritedTemplateItem.ID || itemTemplate.InheritsFrom(inheritedTemplateItem.ID, item.Database));
    }
}


    public static class TemplateExtensions
{
    public static ID StandardTemplateId = ID.Parse("{1930BBEB-7805-471A-A3BE-4858AC7CF696}");

    /// <summary>
    /// 
    /// </summary>
    /// <param name="template"></param>
    /// <param name="inheritedId"></param>
    /// <param name="database"></param>
    /// <returns></returns>
    public static bool InheritsFrom(this Template template, ID inheritedId, Database database)
    {
        if (template == null || database == null)
        {
            return false;
        }

        if (template.ID == inheritedId)
        {
            return true;
        }

        var hasBaseTemplate = template.BaseIDs.Any(baseId => baseId == inheritedId);

        if (hasBaseTemplate)
        {
            return true;
        }

        var baseTemplates = template.BaseIDs
                                    .Where(baseId => baseId != TemplateExtensions.StandardTemplateId)
                                    .Select(baseId => TemplateManager.GetTemplate(baseId, database));

        return baseTemplates.Any(baseTemplate => baseTemplate != null && baseTemplate.InheritsFrom(inheritedId, database));
    }
}