> ## Documentation Index
> Fetch the complete documentation index at: https://docs.on-it.no/llms.txt
> Use this file to discover all available pages before exploring further.

# Create event listeners

All event listeners will inherit from IEventListener\<T> where T is a Zpider event.

## Available events

All events are in the namespace `Zpider.eShop.Web.Base.Plugins.Events`

| Name                      | Description                                                          |
| ------------------------- | -------------------------------------------------------------------- |
| AddToCartBeforeSaveEvent  | Fired when an item is added to the cart, but before the cart i saved |
| AddToCartEvent            | Fired after an item is added to the cart                             |
| ClearCacheEvent           | Fired when an admin clicks "Clear cache"                             |
| LogonUserEvent            | Fired when a user (or guest) is logged on                            |
| NewUserBeforeSaveEvent    | Fired before a new user is saved                                     |
| NewUserEvent              | Fired when a new user is created                                     |
| OrderStep1Event           | Fired in orderstep1                                                  |
| OrderStep2Event           | Fired in orderstep2                                                  |
| PageLoadEvent             | Fired for each page load                                             |
| PlaceOrderBeforeSaveEvent | Fired before an order is placed                                      |
| PlaceOrderEvent           | Fired after an order is placed                                       |

## Example

This is the code behind the Trustpilot integration in Zpider. In this example we are listening for both the PageLoadEvent in order to inject a trustbox using the PageBuilderService and a PlaceOrderEvent to pass a copy of the order to Trustpilot so that they can send an invitation when the order is ready.

```csharp theme={null}
using Newtonsoft.Json;
using System;
using System.Threading.Tasks;
using System.Web;
using Zpider.eShop.Lib;
using Zpider.eShop.Lib.Configuration;
using Zpider.eShop.Web.Base;
using Zpider.eShop.Web.Base.Plugins;
using Zpider.eShop.Web.Base.Plugins.Events;
using Zpider.eShop.Web.Base.Plugins.Providers;
using Zpider.eShop.Web.Base.Services;
using Zpider.eShop.Web.Config;

namespace Plugin.Trustpilot
{
    public class TrustpilotPlugin : ZpiderPlugin
    {
        private readonly Func<IPluginInstaller> installer;
        public const string IntegrationKey = nameof(IntegrationKey);
        public const string TrustBox = nameof(TrustBox);
        public TrustpilotPlugin(Func<IPluginInstaller> installer)
        {
            this.installer = installer;
        }
        public override Task Install()
        {
            installer().Module("TRUSTPILOT", module =>
            {
                module.SetProperty(IntegrationKey, "");
                module.SetProperty(TrustBox, module.GetProperty<bool>(TrustBox, true));
            }
            ).Commit();
            return base.Install();
        }
    }

    public class TrustpilotPageloadListener : IEventListener<PageLoadEvent>
    {
        public int Priority => 0;

        public IPageBuilderService PageBuilderService { get; }

        public TrustpilotPageloadListener(IPageBuilderService pageBuilderService)
        {
            PageBuilderService = pageBuilderService;
        }

        public void Handle(PageLoadEvent zpiderEvent)
        {
            var module = Domain.Configuration.Modules["TRUSTPILOT"] as Module;
            if (module?.GetProperty<bool>("TrustBox") == true)
                PageBuilderService.AppendHeadContent(@"<!-- TrustBox script --><script type='text/javascript' src='//widget.trustpilot.com/bootstrap/v5/tp.widget.bootstrap.min.js' async></script><!--End TrustBox script-->");
            if (!string.IsNullOrEmpty(module?.GetProperty<string>(TrustpilotPlugin.IntegrationKey)))
            {
                PageBuilderService.AppendHeadContent($@"<script>
        (function(w,d,s,r,n){{w.TrustpilotObject = n;w[n]=w[n]||function(){{(w[n].q=w[n].q||[]).push(arguments)}};
            a=d.createElement(s);a.async=1;a.src=r;a.type='text/java'+s;f=d.getElementsByTagName(s)[0];
            f.parentNode.insertBefore(a,f)}})(window,document,'script', 'https://invitejs.trustpilot.com/tp.min.js', 'tp');
            tp('register', '{module.GetProperty<string>(TrustpilotPlugin.IntegrationKey)}');</script>");
            }
        }
    }

    public class TrustpilotOrderListener : IEventListener<PlaceOrderEvent>
    {
        public int Priority => 0;

        public IPageBuilderService PageBuilderService { get; }

        public TrustpilotOrderListener(IPageBuilderService pageBuilderService)
        {
            PageBuilderService = pageBuilderService;
        }

        public void Handle(PlaceOrderEvent zpiderEvent)
        {
            var order = zpiderEvent.ZpiderOrder as ZpiderOrderDataClass;
            var lines = order.ZpiderOrderLine;
            var invitation = new TrustpilotInvitation
            {
                recipientEmail = order.bdGetString((int)ZpiderOrderFields.Email),
                recipientName = order.bdGetString((int)ZpiderOrderFields.Name),
                referenceId = $"ORDER{order.bdGetString((int)ZpiderOrderFields.ZpiderOrderNo)}",
                source = "InvitationScript"
            };
            using (var art = Domain.MainClass.CreateDataClass("article") as BaseTableDataClass)
            {
                foreach (ZpiderOrderLineDataClass line in lines)
                {
                    art.bdSetFilterCondition(ArticleFields.Number, line.bdGetString((int)ZpiderOrderLineFields.ArticleNumber));
                    if (art.bdRequeryFilterCondition() == ErrorCodes.None && art.bdFetchFirst() == ErrorCodes.None)
                    {
                        var item = new Product
                        {
                            name = line.bdGetString((int)ZpiderOrderLineFields.Name),
                            sku = line.bdGetString((int)ZpiderOrderLineFields.ArticleNumber),
                            imageUrl = $"https://{HttpContext.Current.Request.Url.Host}/ErpImages/{line.bdGetString((int)ZpiderOrderLineFields.ArticleNumber)}",
                            productUrl = $"https://{HttpContext.Current.Request.Url.Host}{Domain.Resolve<IUrlProvider>().GetUri(line.bdGetString((int)ZpiderOrderLineFields.ArticleNumber), line.bdGetString((int)ZpiderOrderLineFields.Name), art.bdGetInt((int)ArticleFields.GroupNumber), "product")}"
                        };
                        invitation.products.Add(item);
                    }
                }
            }
            PageBuilderService.AppendFootContent(@"
<script>
document.addEventListener('DOMContentLoaded', function() {
    if(tp) tp('createInvitation', " + JsonConvert.SerializeObject(invitation) + @");
	});
</script>");
        }
    }
}
```