WPSC in MOSS2007 - "Cannot retrieve properties at this time. "

Introduction

Web Part Service Component (WPSC) is a nice staff for SharePoint developers working on client side programming. It supplies SharePoint Web Parts objects combined with HTML objects for developers to practice on web part management.

Background

There seems no so much changes on the object level between SharePoint 2003 and SharePoint 2007. There is one more property in WPSC 3.0 than WPSC 2.0 called WebServerRelativeURL Property. But things seems like not so simple because the way WPSC register web part changed...

In WSS 2.0, WPSC register a web part using the token like WPQ1, WPQ2, WPQ3 ...

WPSC.Init(document);var varPartWPQ7 = WPSC.WebPartPage.Parts.Register('WPQ7',
    '6b93d728-6d3e-47cb-9917-37cfd0aff443',document.all.item('WebPartWPQ7'));
var varPartWPQ3 = WPSC.WebPartPage.Parts.Register('WPQ3',
    '32950565-92aa-4a11-92b0-9dcff1b4e956',document.all.item('WebPartWPQ3'));
var varPartWPQ2 = WPSC.WebPartPage.Parts.Register('WPQ2',
    '338c0c38-b8cb-4ea2-918e-2d5c632df2bd',document.all.item('WebPartWPQ2'));
var varPartWPQ4 = WPSC.WebPartPage.Parts.Register('WPQ4',
    '3612bf7c-595c-48fe-aaf4-87cbb89078a2',document.all.item('WebPartWPQ4'));
var varPartWPQ5 = WPSC.WebPartPage.Parts.Register('WPQ5',
    '43bf7599-0acf-41d7-b3f5-397cbc7eca6b',document.all.item('WebPartWPQ5'));
var varPartWPQ6 = WPSC.WebPartPage.Parts.Register('WPQ6',
    '4623b8c7-989f-471c-a3fa-7f53148acdcd',document.all.item('WebPartWPQ6'));
var varPartWPQ1 = WPSC.WebPartPage.Parts.Register('WPQ1',
    '056d0533-514b-42e1-8925-38bf2c5b3b07',document.all.item('WebPartWPQ1'));  

In WSS 3.0, WPSC register a web part using the same tokens as WSS2.0, but the WPQ1 is used for register a null web part. If you try to access its properties, you will get error:

"Cannot retrieve properties at this time."

var varPartWPQ4 = WPSC.WebPartPage.Parts.Register('WPQ4',
    'e2412c24-1c4f-4545-93dc-2a4e965b2032',document.all.item('WebPartWPQ4'));
var varPartWPQ5 = WPSC.WebPartPage.Parts.Register('WPQ5',
    '77cbc2a3-c770-4a7d-9024-63b78cc45ff4',document.all.item('WebPartWPQ5'));
var varPartWPQ6 = WPSC.WebPartPage.Parts.Register('WPQ6',
    'f4481df0-a93d-495d-bcb6-fa686bbd9816',document.all.item('WebPartWPQ6'));
var varPartWPQ7 = WPSC.WebPartPage.Parts.Register('WPQ7',
    '1fddcba4-7b65-40d9-972f-d6ee86a224f4',document.all.item('WebPartWPQ7'));
var varPartWPQ1 = WPSC.WebPartPage.Parts.Register('WPQ1',
    '00000000-0000-0000-0000-000000000000',document.all.item('WebPartWPQ1')); 

Let's go through one sample code which will collect the web part titles

if(typeof(WPSC) == 'undefined')
  return;
  
 if(WPSC.WebPartPage)
  PortalPartsCollection = WPSC.WebPartPage.Parts; 
 
 if(PortalPartsCollection) 
 { 
  for(var i=0; i< PortalPartsCollection.Count; i++) 
  { 
   var objWebPart = PortalPartsCollection.Item(i); 
    
   if(objWebPart.WebPartQualifier == "WPQ1")
    continue;
     
   if(objWebPart.Properties.Count() > 0)
   {  
    var webpartTitle = objWebPart.Properties.Item(
       "%22http://schemas.microsoft.com/WebPart/v2#Title%22%29.Value"">http://schemas.microsoft.com/WebPart/v2#Title").Value;
    PortalPartsTitleCollection.push(webpartTitle);
    
    var targetObject = searchTargetNode(objWebPart);    
    if(targetObject)
      targetObject.innerHTML = createArchor(webpartTitle) + targetObject.innerHTML;
   }   
  } 
 }

In the code above, we can see the web part with WebPartQualifier "WPQ1" will be ignored.

History

This is the first version.