Unable to get the getting null in the context

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ServiceModel;
using Microsoft.Xrm.Sdk;
namespace kb
{
public class customFields:IPlugin
{
public void Execute(IServiceProvider serviceProvider)
{
// Obtain the tracing service
ITracingService tracingService =
(ITracingService)serviceProvider.GetService(typeof(ITracingService));

// Obtain the execution context from the service provider.
IPluginExecutionContext context = (IPluginExecutionContext)
serviceProvider.GetService(typeof(IPluginExecutionContext));

// The InputParameters collection contains all the data passed in the message request.
if (context.InputParameters.Contains("Target") &&
context.InputParameters["Target"] is Entity)
{
// Obtain the target entity from the input parameters.
Entity entity = (Entity)context.InputParameters["Target"];

// Obtain the organization service reference which you will need for
// web service calls.
IOrganizationServiceFactory serviceFactory =
(IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
IOrganizationService service = serviceFactory.CreateOrganizationService(context.UserId);

try
{
// Plug-in business logic goes here.
if (entity.Contains("kamran_name") && entity["kamran_name"] != null)
{
string name = (string)entity["kamran_name"];
entity["kamran_setname"] = name;
}

}

catch (FaultException<OrganizationServiceFault> ex)
{
throw new InvalidPluginExecutionException("An error occurred in the plugin.", ex);
}

catch (Exception ex)
{
tracingService.Trace("Plugin: {0}", ex.ToString());
throw;
}
}

}
}
}