Using SharePoint Custom Application pages as SharePoint List Forms

I was surprised to know that I can develop a SharePoint custom application page that can be used as one of the SharePoint list forms (NewForm.aspx, EditForm.aspx and DispForm.aspx). This can be done by writing a custom list definition. The code snippet is as follows.

<XmlDocuments>
<XmlDocument NamespaceURI="http://schemas.microsoft.com/sharepoint/v3/contenttype/forms/url"&gt;

<FormUrls
xmlns="http://schemas.microsoft.com/sharepoint/v3/contenttype/forms/url">
<Display>_layouts/ProjectName/Ticket List Forms/TicketsDisplayForm.aspx </Display>

<Edit>_layouts/ProjectName/Ticket List Forms/TicketsEditForm.aspx</Edit>

<New>_layouts/ProjectName/Ticket List Forms/TicketsNewForm.aspx</New>

</FormUrls>

</XmlDocument>

</XmlDocuments>

Where TicketsDisplayForm.aspx, TicketsEditForm.aspx and TicketsNewForm.aspx are SharePoint custom application pages deployed to layouts folder.

If we place this snippet in the list definition,and when we click on "New Item" button on the list it will open SharePoint custom application page "TicketsDisplayForm.aspx". In this case we have to handle all the operations like inserting list items in to the list by ourself. You might me wondering why I have to do this? I had to do this since everyone on this list has read-only permission and List item insertion is done by using impersination. We have to take this route since the system is designed to work on role based.