Struggling to understand why adding a web part to a web part zone is so difficult

Question

It's rather frustrating that a task such as ensuring a web part zone has a certain web part in it (on a page layout) is such a difficult or, at the very least, tricky task considering it's surely included in many specifications!?

1. I've tried the xml approach to this: http://sharepointsearch.com/cs/blogs/sharepointblogs/archive/2007/11/23/adding-custom-webparts-in-a-sharepoint-site-definition.aspx
2. And even used the following server control to try and achieve it: http://code.msdn.microsoft.com/Adding-default-web-parts-ab7aec72

The problem with solution 1 is that every time I switch between a new page layout - the web part's added again (as explained in the article link in solution number 2). Not to mention the fact that every time I deploy a page layout with this xml a duplicate web part is added (which then calls the need for a feature event receiver!!).

The problem with solution 2 is similar - in the fact that when I switch between page layouts - the web part is added to completely different web part zones on completely different pages!

I'd really appreciate any help anyone can offer on this.

Answer 1

The way I do this is similar to #2, but when I add the webpart, I store it's ID into the SPWeb property bag so I know whether I've added the webpart to the page or not:

if (web.AllProperties.ContainsKey("MY_WEBPART_ID")) return;

WebPart webPart = new MyWebPart();

using (SPLimitedWebPartManager mgr = web.GetLimitedWebPartManager("Default.aspx", System.Web.UI.WebControls.WebParts.PersonalizationScope.Shared))
{
    try
    {
        mgr.AddWebPart(webPart, "MiddleLeftZone", 2);
    }
    finally
    {
        if (mgr != null &&
            mgr.Web != null)
        {
            mgr.Web.Dispose();
        }
    }
}
web.AllProperties["MY_WEBPART_ID"] = webpart.ID;

You can always loop through the webparts on the page and make sure it's not currently on there before you add it:

Guid webPartId = new Guid(web.AllProperties["MY_WEBPART_ID"]);
using (SPLimitedWebPartManager mgr = web.GetLimitedWebPartManager("Default.aspx", System.Web.UI.WebControls.WebParts.PersonalizationScope.Shared))
{
    try
    {
        foreach (WebPart wp in mgr.WebParts)
        {
            if (wp.ID == webPartId)
            {
                return;
            }
        }

        WebPart webPart = new MyWebPart();
        mgr.AddWebPart(webPart, "MiddleLeftZone", 2);
        web.AllProperties["MY_WEBPART_ID"] = webpart.ID;
    }
    finally
    {
        if (mgr != null &&
            mgr.Web != null)
        {
            mgr.Web.Dispose();
        }
    }
}

P.S. Some of the code above is just from memory, make sure you debug it first to make sure it works as expected.