c# asp.net

[salahuddin]

Error show:The type or namespace name 'DeveloperReportEntities' could not be found (are you missing a using directive or an assembly reference?)
how can i solve this problem, could u please give any solution

//using System;
//using System.Collections.Generic;
//using System.Linq;
//using System.Web;
 
//namespace TaxSolutions.Models
//{
//    public class UserManager
//    {
//    }
//}
using System;
using System.Linq;
using System.Data.EntityModel;
using System.Web;
using System.Collections.Generic;
using TaxSolutions.Models.DB;
using TaxSolutions.Models.ViewModels;
using TaxSolutions.Models;
 
namespace TaxSolutions.Models.ObjectManager
{
   public class UserManager {
 
        private DeveloperReportEntities dre = new DeveloperReportEntities();
 
        public void Add(UserView user) {
            DB.SysUser sysUser = new DB.SysUser();
            sysUser.SysUserLoginID = user.LoginID;
            sysUser.SysPassword = user.Password;
            sysUser.FirstName = user.FirstName;
            sysUser.LastName = user.LastName;
            sysUser.ContactNumber = user.LastName;
 
            dre.AddToSysUsers(sysUser);
            dre.SaveChanges();
        }
 
        public bool IsUserLoginIDExist(string userLogIn) {
            return (from o in dre.SysUsers where o.SysUserLoginID == userLogIn select o).Any();
        }
    }
}

[JamesGaunt]

To fix this you'll need to find out where the class DeveloperReportEntities is defined.

The class must be defined in an assembly somewhere, and within that assembly the class will be defined within a specific namespace.

So you need to do 2 things:

- Firstly ensure you have referenced the assembly in your Visual Studio project. Right click on References in Solution Explorer and select Add Reference, then find the assembly to add it.
- Secondly add the appropriate 'using ...' to the top of the file to include the namespace that the class resides in.

This doesn't help you find where the class is defined however. For that you'll need to look at the documentation for the library you are using.