在C＃中动态设置查询类型

Question

I need your help. I wanna implement a database request with different types depending on the users role.

My current query looks like this:

var myVar = session
            .Query<TypeA>()
            .Where(xyz)
            .ToList();

Now I wanna do it like this:

if(UserIsAdmin)
     Type T = TypeA;
else
     Type T = TypeB;

var myVar= session
           .Query<T>()
           .Where(xyz)
           .ToList();

Notice TypeA an TypeB should be dynamically changed in .Query<T> .

Is there any good way to do this? Do you need more information?

Thanks in advance :-)

EDIT:

The scenario looks as follows:

I have to get different models from the database depending on the users roles. Lets say the user is Admin he can see firstname, lastname, address , if not he can only see firstname, lastname .

I thought to create two different models with these attributes and change the type in the query dynamically.

Answer 1

You need to understand first the consept of seperating layers.

So first of all you will have a DB layer , which in your case(though i don't know you db schema), but it should look something like:

public class UsersDbServices 
{
    public UserDbEntity GetUserById(int userId)
    {
        UserDbEntity user = null
        using (context..)
        {
            user = context.Users.Where(u=> u.Id = userId).FirstOfDefault();
        }

        return user;
    }
}

You will call this service from you Logic layer, note that you can use the same method for both normal user and administrator !

Now for the clinet side I would return a DTO(data transfer object) which will be the same for both cases!:

public class UserDTO
{
    public int UserId { get;set;}
    public string FirstName { get;set;}
    public string LastName { get;set;}
    public string Address { get;set;}       
}

Now the last part is the controller, here you will get the data from the DBLayer (you can go through another layer of logic, but lets say its not a must), and what you will do now in the controller you can poppulate the DTO (and again you can do this all in the logic layer as well) in this way:

public class UsersController
{
    UsersDbServices m_UsersDbServices = new UsersDbServices ();

    [HttpGet]
    public UserDTO GetUserById(userId)
    {
        UserDTO retVal = null;

        UserDbEntity userDbEntity  = m_UsersDbServices.GetUserById(userId);
        if(userDbEntity == null){
            throw...
        }

        retVal = new UserDTO()
        {
            FirstName  = userDbEntity.FirstName;
            ...
        };

        if(!UserIsAdmin) <- kept it as a bool here
        {   
            retVal.Address  = null;
        }

        return retVal; <- convert to json
    }
}

Another approach is to use another DTO like AdminUserDTO and RegularUserDTO