I used a eventhandler for that. This prevents deleting and unpublishing for certain doctypes

namespace Customer.Cms.Events
{
    using System.Collections.Generic;
    using System.Linq;

    using Umbraco.Core;
    using Umbraco.Core.Services;

    /// <summary>
    /// The prevent delete event handler
    /// </summary>
    public class PreventDelete : ApplicationEventHandler
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="PreventDelete"/> class.
        /// </summary>
        public PreventDelete()
        {
            ContentService.Trashing += this.ContentServiceTrashing;
            ContentService.UnPublishing += this.ContentServiceUnPublishing;
        }

        /// <summary>
        /// Gets the content types to prevent deleting and unpublishing for
        /// </summary>
        private IEnumerable<string> ContentTypes
        {
            get
            {
                return new[]
                           {
                               "Homepage",
                               "Settings"
                           };
            }
        }

        /// <summary>
        /// The content trashing event handler
        /// </summary>
        /// <param name="sender">
        /// The sender.
        /// </param>
        /// <param name="e">
        /// The e.
        /// </param>
        private void ContentServiceTrashing(IContentService sender, Umbraco.Core.Events.MoveEventArgs<Umbraco.Core.Models.IContent> e)
        {
            if (this.ContentTypes.Contains(e.Entity.ContentType.Alias))
            {
                e.Cancel = true;
            }
        }

        /// <summary>
        /// The content unpublishing event handler
        /// </summary>
        /// <param name="sender">
        /// The sender.
        /// </param>
        /// <param name="e">
        /// The e.
        /// </param>
        private void ContentServiceUnPublishing(Umbraco.Core.Publishing.IPublishingStrategy sender, Umbraco.Core.Events.PublishEventArgs<Umbraco.Core.Models.IContent> e)
        {
            foreach (var item in e.PublishedEntities)
            {
                if (this.ContentTypes.Contains(item.ContentType.Alias))
                {
                    e.Cancel = true;
                    break;
                }
            }
        }
    }
}

Dave

And here is a eventhandler to allow certain doctypes only once in your site

namespace Customer.Cms.Events
{
    using System.Collections.Generic;
    using System.Linq;

    using Umbraco.Core;
    using Umbraco.Core.Models;
    using Umbraco.Core.Services;

    /// <summary>
    /// Allow document types to be created once
    /// </summary>
    public class AllowOnce : ApplicationEventHandler
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="AllowOnce"/> class.
        /// </summary>
        public AllowOnce()
        {
            ContentService.Creating += this.ContentServiceCreating;
        }

        /// <summary>
        /// Gets the content types that are allowed once under the parent
        /// </summary>
        private IEnumerable<string> ContentTypes
        {
            get
            {
                return new[]
                           {
                               "Homepage",
                               "Settings"
                           };
            }
        }

        /// <summary>
        /// The content service_ creating.
        /// </summary>
        /// <param name="sender">
        /// The sender.
        /// </param>
        /// <param name="e">
        /// The e.
        /// </param>       
        private void ContentServiceCreating(IContentService sender, Umbraco.Core.Events.NewEventArgs<IContent> e)
        {
            if (this.ContentTypes.Contains(e.Entity.ContentType.Alias))
            {
                if (e.ParentId == -1 && e.Entity.ContentType.Alias == DocumentTypes.Homepage.Alias)
                {
                    // only allow one homepage
                    e.Cancel = true;
                }
                else
                {
                    IContent parent = sender.GetById(e.ParentId);
                    if (parent != null)
                    {
                        if (parent.Children().Any(x => x.ContentType.Alias == e.Entity.ContentType.Alias))
                        {
                            e.Cancel = true;
                        }
                    }
                }
            }
        }
    }
}

Hi Dawoe,

Thanks for the fast reply!
I'll try this solution in our next site.

Kind regards,

Frans

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