ExmMessageActivator.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.UI.WebControls;
using Sitecore.Modules.EmailCampaign.Application.EmailDispatch;

namespace Foundation.xDB.sitecore.admin
{
    public partial class ExmMessageActivator : System.Web.UI.Page
    {
        private IEmailDispatch _emailDispatch;
        private const string EmailXpath = "/sitecore/content/Email//*[@@templateid='{078D8A76-F971-4891-B422-76C0BCF9FA03}']";

        public ExmMessageActivator()
        {
            _emailDispatch = Sitecore.Modules.EmailCampaign.Application.Application.Instance.EmailDispatch;
        }

        protected void btnActivate_Click(object sender, EventArgs e)
        {
            var items = GetItems(false);

            foreach (var item in items)
            {
                _emailDispatch.Activate(item);
            }
        }

        protected void btnDeactivate_Click(object sender, EventArgs e)
        {
            var items = GetItems(true);

            foreach (var item in items)
            {
                _emailDispatch.Deactivate(item);
            }
        }

        private List<Guid> GetItems(bool isReadOnly)
        {
            return Sitecore.Data.Database.GetDatabase("master")
                        .SelectItems(EmailXpath)
                        .Where(x => x.Appearance.ReadOnly == isReadOnly)
                        .Select(x => x.ID.Guid)
                        .ToList();
        }
    }
}