how to update unicode character in gridview

You must set Request and Response encoding for your page/application to support UTF. Also, make sure that the datatype for the coulmn that store the data must be NVARCHAR(in case you are using MS-SQL Server). To set page level encoding add:

<![CDATA[<%@ Page ResponseEncoding="utf-8" RequestEncoding="utf-8"%>]]>

at the top of your page. And to set application level encoding add:

<configuration>
   <system.web>
      <globalization
           requestEncoding="utf-8"
           responseEncoding="utf-8"
        />
   </system.web>
</configuration>

in your web.config file. Hope it helps.