sandbox solution

http://msdn.microsoft.com/en-us/library/ff798382.aspx

Cascadin Dropdown in Sharepoint2010

Down Load Js file from this Link
http://www.c-sharpcorner.com/uploadfile/Roji.Joy/cascading-dropdown-in-share-point-using-jquery/

<script language="javascript" type="text/javascript" src="../../jQuery%20Libraries/jquery-1.8.2.js"></script>
<script language="javascript" type="text/javascript" src="../../jQuery%20Libraries/jquery.SPServices-0.7.2.min.js"></script>
<script language="javascript" type="text/javascript">
$(document).ready(function() {
  $().SPServices.SPCascadeDropdowns({
    relationshipList: "Regions",
    relationshipListParentColumn: "Country",
    relationshipListChildColumn: "Title",
    CAMLQuery: "<Eq><FieldRef Name='Status'/><Value Type='Text'>Active</Value></Eq>",   parentColumn: "Country",
    childColumn: "Region",
    debug: true
  });
  $().SPServices.SPCascadeDropdowns({
    relationshipList: "States",
    relationshipListParentColumn: "Region_x0020_Name",
    relationshipListChildColumn: "Title",
    relationshipListSortColumn: "ID",
    parentColumn: "Region",
    childColumn: "State"
  });
});
</script>


Fore More info ref links..
http://basquang.wordpress.com/2010/09/21/spservices-cascading-drop-down-list-in-sharepoint-2010-list-using-jquery/

 

How To Use Multiline Text Field as Calculated Column in Sharepoint?

Following are the Steps to use Multiline Text Field as Calculated Column: 

1. Create a Single line text column . ex, Newsfeed

2. Create a calculated column using the above single line text column.(and select number as data type if u renders any html output )

3. Delete the Single line text column created on step1.

4. Create the multi line text column with the same name as single line text column has,ex Newsfeed.

Now the multiline text is used as calculated column ..

Note: If U want to display any string as Html rendering y must follow above steps..

Client Object Model Architecture Sharepoint2010

The Architecture of Client Object Model, and understand how it functions,



As can be seen in the above diagram all versions of the Client OM go through the WCF Web Service namedClient.svc. This Web Service is located, along with all other SharePoint Web Services, in the folder [SharePoint Root]\ISAPI. The Client OM is responsible for packaging any requests into XML and calling the Web Server, however, when this call takes place is controlled by the developer as you will see. The response from the Client.svc Web Service is sent as JSON and the Client OM is responsible for transforming this into appropriate objects for use in the environment the call was made from.

   The SharePoint Client Object Model is supported in three environments; .NET managed code, JavaScript and SilverLight.

.NET Managed Code Assemblies

To use the Client Object Model in .NET Managed code you must add references to two assemblies in your Visual Studio project. Both of these assemblies can be found in [SharePoint Root]\ISAPI folder, which is typically C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\ISAPI\.

Microsoft.SharePoint.Client.dll (282kb)
Microsoft.SharePoint.Client.Runtime.dll (146kb)

As you can see from the indicated sizes these are not large assemblies and won't bloat an application very much. Despite their relatively diminutive size however they pack a great deal of punch, as you will soon see.

Silverlight Assemblies

Just like .NET managed code, to use the SharePoint Client OM from within a Silverlight application you must add two assemblie references. These assemblies are a little trickier to find and are located in the [SharePoint Root]\Templates\Layouts\ClientBin folder.

Microsoft.SharePoint.Client.Silverlight.dll (266kb)
Microsoft.SharePoint.Client.Silverlight.Runtime.dll (142kb)

The location is understandable considering the the Layout folder is mapped to each SharePoint Web Application and the heavy use of Silverlight within SharePoint 2010. You will notice the size of these assemblies is just slightly smaller than their .NET managed code counterparts. Despite this, there is no difference in functionality.

JavaScript code(ECMA Script) 

To make use of the Client OM in JavaScript you must include the SP.js file on the page. The corresponding SP.Runtime.js will be added automatically by SharePoint.

Object Models Comparision :

Server OM	Client OM
SPContext	ClientContext
SPSite	Site
SPWeb	Web
SPList	List
SPListItem	ListItem

SPService and Jquery

http://sympmarc.com/page/2/

SP 2010: Introduction to programmatically working with Taxonomies in SharePoint Server 2010

http://zimmergren.net/technical/sp-2010-introduction-to-programmatically-working-with-taxonomies-in-sharepoint-server-2010

Cascading dropdown (or) Filtered Values in Lookup Columns in SharePoint

Please see the below link..

http://sharepoint-works.blogspot.in/2012/02/cascading-dropdown-or-filtered-values.html#.USOhOB0_taY