How many times have you discovered that you need to reuse some fields defined in a data template, but don’t want to use that data template as a base template since it defines a bunch of fields that you don’t want to use?

What do you usually do in such a situation?

In the past, I would have created a new data template, moved the fields I would like to reuse underneath it, followed by setting that new template as a base template on the data template I moved the fields from.

I’ve spoken with other Sitecore developers on what they do in this situation, and one developer conveyed he duplicates the template, and delete fields that are not to be reused — thus creating a new base template. Though this might save time, I would advise against it — any code referencing fields by IDs will break using this paradigm for creating a new base template.

Martin Fowler — in his book
Refactoring: Improving the Design of Existing Code — defined the refactoring technique ‘Pull Up Field’ for moving fields from a class up into its base class — dubbed superclass for the Java inclined audience.

One should employ this refactoring technique when other subclasses of the base class are to reuse the fields being pulled up.

When I first encountered this refactoring technique in Fowler’s book, I pondered over how useful this would be in the Sitecore data template world, and decided to build two tools for pulling up fields into a base template. One tool will create a new base template, and the other will allow users to move fields to an existing base template.

The following class defines methods that will be used by two new client pipelines I will define below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Sitecore.Configuration;
using Sitecore.Data;
using Sitecore.Data.Items;
using Sitecore.Data.Managers;
using Sitecore.Data.Templates;
using Sitecore.Diagnostics;
using Sitecore.Shell.Applications.Dialogs.ItemLister;
using Sitecore.Shell.Framework;
using Sitecore.Text;
using Sitecore.Web;
using Sitecore.Web.UI.Sheer;

namespace Sitecore.Sandbox.Shell.Framework.Pipelines
{
    public class PullUpFieldsIntoBaseTemplate
    {
        private const char IDDelimiter = '|';
        private const string BaseTemplateFieldName = "__Base template";
        
        public void EnsureTemplate(ClientPipelineArgs args)
        {
            Item item = GetItem(args);
            if (!IsTemplate(item))
            {
                CancelOperation(args, "The supplied item is not a template!");
            }
        }

        private static bool IsTemplate(Item item)
        {
            Assert.ArgumentNotNull(item, "item");
            return TemplateManager.IsTemplate(item);
        }

        public void SelectFields(ClientPipelineArgs args)
        {
            Assert.ArgumentNotNull(args, "args");
            if (!args.IsPostBack)
            {
                UrlString urlString = new UrlString(UIUtil.GetUri("control:TreeListExEditor"));
                UrlHandle urlHandle = new UrlHandle();
                urlHandle["title"] = "Select Fields";
                urlHandle["text"] = "Select the fields to pull up into a base template.";
                urlHandle["source"] = GetSelectFieldsDialogSource(args);
                urlHandle.Add(urlString);
                SheerResponse.ShowModalDialog(urlString.ToString(), "800px", "500px", string.Empty, true);
                args.WaitForPostBack();
            }
            else if (args.HasResult)
            {
                args.Parameters["fieldIds"] = args.Result;
                args.IsPostBack = false;
            }
            else
            {
                CancelOperation(args);
            }
        }

        private static string GetSelectFieldsDialogSource(ClientPipelineArgs args)
        {
            Assert.ArgumentNotNull(args, "args");
            Assert.ArgumentNotNullOrEmpty(args.Parameters["database"], "args.Parameters[\"database\"]");
            Assert.ArgumentNotNullOrEmpty(args.Parameters["templateId"], "args.Parameters[\"templateId\"]");
            return string.Format
            (
                "AllowMultipleSelection=true&DatabaseName={0}&DataSource={1}&IncludeTemplatesForSelection=Template field",
                args.Parameters["database"],
                args.Parameters["templateId"]
            );
        }

        public void ChooseBaseTemplateName(ClientPipelineArgs args)
        {
            if (!args.IsPostBack)
            {
                SheerResponse.Input("Enter the name of the base template", string.Concat("New Base Template 1"));
                args.WaitForPostBack();
            }
            else if (args.HasResult)
            {
                args.Parameters["baseTemplateName"] = args.Result;
                args.IsPostBack = false;
            }
            else
            {
                CancelOperation(args);
            }
        }

        public void ChooseBaseTemplateLocation(ClientPipelineArgs args)
        {
            if (!args.IsPostBack)
            {
                Dialogs.BrowseItem
                (
                    "Select Base Template Location",
                    "Select the parent item under which the new base template will be created.",
                    args.Parameters["icon"],
                    "OK",
                    "/sitecore/templates",
                    args.Parameters["templateId"]
                );

                args.WaitForPostBack();
            }
            else if (args.HasResult)
            {
                args.Parameters["baseTemplateParentId"] = args.Result;
                args.IsPostBack = false;
            }
            else
            {
                CancelOperation(args);
            }
        }

        public void CreateNewBaseTemplate(ClientPipelineArgs args)
        {
            Database database = GetDatabase(args.Parameters["database"]);
            Item baseTemplateParent = database.GetItem(args.Parameters["baseTemplateParentId"]);
            Item baseTemplate = baseTemplateParent.Add(args.Parameters["baseTemplateName"], new TemplateID(TemplateIDs.Template));
            SetBaseTemplateField(baseTemplate, TemplateIDs.StandardTemplate);
            args.Parameters["baseTemplateId"] = baseTemplate.ID.ToString();
        }

        public void ChooseExistingBaseTemplate(ClientPipelineArgs args)
        {
            if (!args.IsPostBack)
            {
                ItemListerOptions itemListerOptions = new ItemListerOptions
                {
                    ButtonText = "OK",
                    Icon = args.Parameters["icon"],
                    Title = "Select Base Template",
                    Text = "Select the base template for pulling up the fields."
                };

                TemplateItem templateItem = GetItem(args);
                itemListerOptions.Items = ExcludeStandardTemplate(templateItem.BaseTemplates).Select(baseTemplate => baseTemplate.InnerItem).ToList();
                itemListerOptions.AddTemplate(TemplateIDs.Template);
                SheerResponse.ShowModalDialog(itemListerOptions.ToUrlString().ToString(), true);
                args.WaitForPostBack();
            }
            else if (args.HasResult)
            {
                args.Parameters["baseTemplateId"] = args.Result;
                args.IsPostBack = false;
            }
            else
            {
                CancelOperation(args);
            }
        }

        private static IEnumerable<TemplateItem> ExcludeStandardTemplate(IEnumerable<TemplateItem> baseTemplates)
        {
            if (baseTemplates != null && baseTemplates.Any())
            {
                return baseTemplates.Where(baseTemplate => baseTemplate.ID != TemplateIDs.StandardTemplate);
            }

            return baseTemplates;
        }

        public void EnsureCanCreateAtBaseTemplateLocation(ClientPipelineArgs args)
        {
            Item baseTemplateParent = GetItem(args.Parameters["database"], args.Parameters["baseTemplateParentId"]);
            if (!baseTemplateParent.Access.CanCreate())
            {
                CancelOperation(args, "You cannot create an item at the selected location!");
            }
        }

        public void Execute(ClientPipelineArgs args)
        {
            Database database = GetDatabase(args.Parameters["database"]);
            Item baseTemplate = database.GetItem(args.Parameters["baseTemplateId"]);
            SetBaseTemplateField(baseTemplate, TemplateIDs.StandardTemplate);
            IDictionary<SectionInformation, IList<Item>> sectionsWithFields = GetSectionsWithFields(database, args.Parameters["fieldIds"]);

            foreach (SectionInformation sectionInformation in sectionsWithFields.Keys)
            {
                IEnumerable<Item> fields = sectionsWithFields[sectionInformation];
                MoveFieldsToAppropriateSection(baseTemplate, sectionInformation, fields);
            }

            Item templateItem = database.GetItem(args.Parameters["templateId"]);
            ListString baseTemplateIDs = new ListString(templateItem[BaseTemplateFieldName], IDDelimiter);
            baseTemplateIDs.Add(baseTemplate.ID.ToString());
            SetBaseTemplateField(templateItem, baseTemplateIDs);
            Refresh(templateItem);
        }

        private static void MoveFieldsToAppropriateSection(Item baseTemplate, SectionInformation sectionInformation, IEnumerable<Item> fields)
        {
            TemplateItem templateItem = baseTemplate;
            TemplateSectionItem templateSectionItem = templateItem.GetSection(sectionInformation.Section.Name);

            if (templateSectionItem != null)
            {
                MoveFields(templateSectionItem, fields);
            }
            else
            {
                Item sectionItemCopy = sectionInformation.Section.CopyTo(baseTemplate, sectionInformation.Section.Name, ID.NewID, false);
                MoveFields(sectionItemCopy, fields);
            }

            if (!sectionInformation.Section.GetChildren().Any())
            {
                sectionInformation.Section.Delete();
            }
        }

        private static void MoveFields(TemplateSectionItem templateSectionItem, IEnumerable<Item> fields)
        {
            Assert.ArgumentNotNull(templateSectionItem, "templateSectionItem");
            Assert.ArgumentNotNull(fields, "fields");
            foreach (Item field in fields)
            {
                field.MoveTo(templateSectionItem.InnerItem);
            }
        }

        private static void SetBaseTemplateField(Item templateItem, object baseTemplateIds)
        {
            Assert.ArgumentNotNull(templateItem, "templateItem");
            templateItem.Editing.BeginEdit();
            templateItem[BaseTemplateFieldName] = EnsureDistinct(baseTemplateIds.ToString(), IDDelimiter);
            templateItem.Editing.EndEdit();
        }

        private static string EnsureDistinct(string strings, char delimiter)
        {
            return string.Join(delimiter.ToString(), EnsureDistinct(strings.ToString().Split(new[] { delimiter })));
        }

        private static IEnumerable<string> EnsureDistinct(IEnumerable<string> strings)
        {
            return strings.Distinct();
        }

        private static IDictionary<SectionInformation, IList<Item>> GetSectionsWithFields(Database database, string fieldIds)
        {
            IDictionary<SectionInformation, IList<Item>> sectionsWithFields = new Dictionary<SectionInformation, IList<Item>>();

            foreach (TemplateFieldItem field in GetFields(database, fieldIds))
            {
                SectionInformation sectionInformation = new SectionInformation(field.Section.InnerItem);
                if (sectionsWithFields.ContainsKey(sectionInformation))
                {
                    sectionsWithFields[sectionInformation].Add(field.InnerItem);
                }
                else
                {
                    sectionsWithFields.Add(sectionInformation, new List<Item>(new[] { field.InnerItem }));
                }
            }

            return sectionsWithFields;
        }

        private static IEnumerable<TemplateFieldItem> GetFields(Database database, string fieldIds)
        {
            ListString fieldIdsListString = new ListString(fieldIds, IDDelimiter);
            IList<TemplateFieldItem> fields = new List<TemplateFieldItem>();

            foreach (string fieldId in fieldIdsListString)
            {
                fields.Add(database.GetItem(fieldId));
            }

            return fields;
        }

        private static Item GetItem(ClientPipelineArgs args)
        {
            Assert.ArgumentNotNull(args, "args");
            Item item = GetItem(args.Parameters["database"], args.Parameters["templateId"]);
            Assert.IsNotNull(item, "Item cannot be null!");
            return item;
        }

        private static Item GetItem(string databaseName, string itemId)
        {
            Assert.ArgumentNotNullOrEmpty(databaseName, "databaseName");
            Assert.ArgumentNotNullOrEmpty(itemId, "itemId");
            ID id = GetID(itemId);
            Assert.IsTrue(!ID.IsNullOrEmpty(id), "itemId is not valid!");
            Database database = GetDatabase(databaseName);
            Assert.IsNotNull(database, "Database is not valid!");
            return database.GetItem(id);
        }

        private static ID GetID(string itemId)
        {
            ID id;
            if (ID.TryParse(itemId, out id))
            {
                return id;
            }

            return ID.Null;
        }

        private static Database GetDatabase(string databaseName)
        {
            Assert.ArgumentNotNullOrEmpty(databaseName, "databaseName");
            return Factory.GetDatabase(databaseName);
        }
        
        private static void CancelOperation(ClientPipelineArgs args)
        {
            Assert.ArgumentNotNull(args, "args");
            CancelOperation(args, "Operation has been cancelled!");
        }

        private static void CancelOperation(ClientPipelineArgs args, string alertMessage)
        {
            Assert.ArgumentNotNull(args, "args");

            if (!string.IsNullOrEmpty(alertMessage))
            {
                SheerResponse.Alert(alertMessage);
            }

            args.AbortPipeline();
        }

        private static void Refresh(Item item)
        {
            Assert.ArgumentNotNull(item, "item");
            Context.ClientPage.ClientResponse.Timer(string.Format("item:load(id={0})", item.ID), 1);
        }

        public class SectionInformation : IEquatable<SectionInformation>
        {
            public Item Section { get; set; }

            public SectionInformation(Item section)
            {
                Assert.ArgumentNotNull(section, "section");
                Section = section;
            }

            public override int GetHashCode()
            {
                return Section.ID.Guid.GetHashCode();
            }

            public override bool Equals(object other)
            {
                return Equals(other as SectionInformation);
            }

            public bool Equals(SectionInformation other)
            {
                return other != null 
                        && Section.ID.Guid == Section.ID.Guid;
            }
        }
    }
}

This above class defines methods that will be used as pipeline processor steps to prompt users for input — via dialogs — needed for pulling up fields to a new or existing base template.

I then defined commands to launch the pipelines I will define later on. I employed the Template method pattern here — each subclass must define its icon path, and the client pipeline it depends on after being clicked:

using System.Collections.Specialized;
using System.Linq;

using Sitecore.Data.Items;
using Sitecore.Data.Managers;
using Sitecore.Diagnostics;
using Sitecore.Shell.Framework.Commands;

namespace Sitecore.Sandbox.Commands.Base
{
    public abstract class PullUpFieldsCommand : Command
    {
        public override void Execute(CommandContext context)
        {
            Assert.ArgumentNotNull(context, "context");
            Context.ClientPage.Start(GetPullUpFieldsClientPipelineName(), CreateNewParameters(GetItem(context)));
        }

        protected abstract string GetPullUpFieldsClientPipelineName();

        private NameValueCollection CreateNewParameters(Item templateItem)
        {
            return new NameValueCollection 
            {
                {"icon", GetIcon()},
                {"database", templateItem.Database.Name},
                {"templateId", templateItem.ID.ToString()}
            };
        }

        protected abstract string GetIcon();

        public override CommandState QueryState(CommandContext context)
        {
            Assert.ArgumentNotNull(context, "context");
            if (ShouldEnable(GetItem(context)))
            {
                return CommandState.Enabled;
            }

            return CommandState.Hidden;
        }

        protected static Item GetItem(CommandContext context)
        {
            Assert.ArgumentNotNull(context, "context");
            Assert.ArgumentNotNull(context.Items, "context.Items");
            Assert.ArgumentCondition(context.Items.Any(), "context.Items", "At least one item must be present!");
            return context.Items.FirstOrDefault();
        }

        private static bool ShouldEnable(Item item)
        {
            return item != null && IsTemplate(item);
        }

        private static bool IsTemplate(Item item)
        {
            Assert.ArgumentNotNull(item, "item");
            return TemplateManager.IsTemplate(item);
        }
    }
}

The command for pulling up fields into a new base template:

using Sitecore.Sandbox.Commands.Base;

namespace Sitecore.Sandbox.Commands
{
    public class PullUpFieldsIntoNewBaseTemplate : PullUpFieldsCommand
    {
        protected override string GetIcon()
        {
            return "Business/32x32/up_plus.png";
        }

        protected override string GetPullUpFieldsClientPipelineName()
        {
            return "uiPullUpFieldsIntoNewBaseTemplate";
        }
    }
}

The command for pulling up fields into an existing base template — it will be visible only when the template has base templates, not including the Standard Template:

using System.Linq;

using Sitecore.Sandbox.Commands.Base;
using Sitecore.Data.Items;
using Sitecore.Diagnostics;

using Sitecore.Shell.Framework.Commands;

namespace Sitecore.Sandbox.Commands
{
    public class PullUpFieldsIntoExistingBaseTemplate : PullUpFieldsCommand
    {
        public override CommandState QueryState(CommandContext context)
        {
            Assert.ArgumentNotNull(context, "context");
            bool shouldEnabled = base.QueryState(context) == CommandState.Enabled 
                                    && DoesTemplateHaveBaseTemplates(context);
            if (shouldEnabled)
            {
                return CommandState.Enabled;
            }

            return CommandState.Hidden;
        }

        private static bool DoesTemplateHaveBaseTemplates(CommandContext context)
        {
            Assert.ArgumentNotNull(context, "context");
            TemplateItem templateItem = GetItem(context);
            return templateItem.BaseTemplates.Count() > 1 
                    || (templateItem.BaseTemplates.Any() 
                            && templateItem.BaseTemplates.FirstOrDefault().ID != TemplateIDs.StandardTemplate);
        }

        protected override string GetIcon()
        {
            return "Business/32x32/up_minus.png";
        }

        protected override string GetPullUpFieldsClientPipelineName()
        {
            return "uiPullUpFieldsIntoExistingBaseTemplate";
        }
    }
}

I’ve omitted how I mapped these to context menu buttons in the core database. If you are unfamiliar with how this is done, please take a look at my first and second posts on augmenting the item context menu to see how this is done.

I registered my commands, and glued methods in the PullUpFieldsIntoBaseTemplate class together into two client pipelines in a configuration include file:

<?xml version="1.0"?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <commands>
      <command name="item:pullupfieldsintonewbasetemplate" type="Sitecore.Sandbox.Commands.PullUpFieldsIntoNewBaseTemplate,Sitecore.Sandbox"/>
      <command name="item:pullupfieldsintoexistingbasetemplate" type="Sitecore.Sandbox.Commands.PullUpFieldsIntoExistingBaseTemplate,Sitecore.Sandbox"/>
    </commands>
    <processors>
      <uiPullUpFieldsIntoNewBaseTemplate>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="EnsureTemplate"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="SelectFields"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="ChooseBaseTemplateName"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="ChooseBaseTemplateLocation"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="EnsureCanCreateAtBaseTemplateLocation"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="CreateNewBaseTemplate"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="Execute"/>
      </uiPullUpFieldsIntoNewBaseTemplate>
      <uiPullUpFieldsIntoExistingBaseTemplate>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="EnsureTemplate"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="SelectFields"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="ChooseExistingBaseTemplate"/>
        <processor mode="on" type="Sitecore.Sandbox.Shell.Framework.Pipelines.PullUpFieldsIntoBaseTemplate,Sitecore.Sandbox" method="Execute"/>
      </uiPullUpFieldsIntoExistingBaseTemplate>
    </processors>
  </sitecore>
</configuration>

The uiPullUpFieldsIntoNewBaseTemplate client pipeline contains processor steps to present the user with dialogs for pulling up fields into a new base template that is created during one of those steps.

The uiPullUpFieldsIntoExistingBaseTemplate pipeline prompts users to select a base template from the list of base templates set on the template.

Let’s see this in action.

I created a template with some fields for testing:

I right-clicked the on my Landing Page template to launch its context menu, and clicked on the ‘Pull Up Fields Into New Base Template’ context menu option:

The following dialog was presented to me for selecting fields to pull up:

I clicked the ‘OK’ button, and was prompted to input a name for a new base template. I entered ‘Page Base’:

After clicking ‘OK’, I was asked to select the location where I want to store my new base template:

Not too long after clicking ‘OK’ again, I see that my new base template was created, and the Title field was moved into it:

Further, I see that my Landing Page template now has Page Base as one of its base templates:

I right-clicked again, and was presented with an additional context menu option to move fields into an existing base template — I clicked on this option:

I then selected the remaining field under the Page Data section:

After clicking ‘OK’, a dialog presented me with a list of base templates to choose from — in this case there was only one base template to choose:

After clicking ‘OK’, I see that the Text field was moved into the Page Base template, and the Page Data section under my Landing Page template was removed:

I hope the above tools will save you time in pulling up fields into base templates.

If you can think of other development tools that would be useful in the Sitecore client, please drop a comment.

Addendum

I have put a polished version of the above onto the Sitecore Marketplace.