Question

for Index action i need to pass Guid but it should be null as i’m checking it for edit or delete action.

I have used like this but getting compile error : Guid Cannot be null must be compile time constant.
or runtime error :

The parameters dictionary contains a null entry for parameter ‘uid’ of non-nullable type ‘System.Guid’ for method ‘System.Web.Mvc.ActionResult Index(System.String, System.Guid)’ in ‘Mapping.Controllers.HomeController’. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.

public ActionResult Index(string userAction, Guid uid = new Guid() )
        {
----
----
}

Answer 1

Try using a nullable Guid for your parameter:

public ActionResult Index(string userAction, Guid? uid = null)

Based on your comments, assuming objModel.Id is a Guid, you can use:

objModel.Id != default(Guid)

However, knowing more about your situation now, I would look to themarcuz‘s answer for a better overall solution.