Add expression in repository base in C#

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Hello all
I am using asp.net 4.5 with code first using the repository pattern in c#.

base class :

C#

public interface IAuditableEntity
        {
            ...
            string DeletedBy { get; set; }
            DateTime? DeletedDate { get; set; }
            bool IsDeleted { get; set; }
        }
    public abstract class AuditableEntity:  IAuditableEntity
            {
                ...
                public string DeletedBy { get; set; }
                public DateTime? DeletedDate { get; set; }
                public bool IsDeleted { get;set; }
            }

class:

C#

public class Group : AuditableEntity
        {
            public int Id {get;set;}
            public string Code { get; set; }
            public string Name { get; set; }
            public GroupType Type { get; set; }
            public string Description { get; set; }
            public int? ParentId { get; set; }
    
        }

Repository Base :

C#

public class RepositoryBase<T> : IRepository<T> where T : class
        {
            protected DbContext _entities;
            protected DbSet<T> dbSet;
            #endregion
            public RepositoryBase(DbContext context)
            {
                _entities = context;
                dbSet = context.Set<T>();
            }
            ...
            public virtual IQueryable<T> GetAll()
            {
                try
                {
                   
                    return dbSet;
                      
                }
                catch (Exception ex)
                {
                    throw ex;
                }
            }
            public virtual IQueryable<T> GetMany(Expression<Func<T, bool>> where)
            {
                return dbSet.Where(where);
            }
           ...
    
    
        }

My Question:
i want to add expression in `GetAll` and `GetMany` function if Repositorybase T use `IAuditableEntry`

What I have tried:

C#

public virtual IQueryable<T> GetAll()
                {
                    try
                    {
                       
                        return dbSet.Where(x=> x is IAuditableEntity && !((IAuditableEntity)x).IsDeleted);
                          
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                }

When i used this
return dbSet.Where(x=> x is IAuditableEntity && !((IAuditableEntity)x).IsDeleted);

it show error like :

The 'TypeIs' expression with an input of type
'Group' and a check of type
'Base.IAuditableEntity' is not supported. Only entity
 types and complex types are supported in LINQ to Entities queries.

Posted 22-Feb-20 18:06pm

sujan_maharjan

Updated 22-Feb-20 23:02pm

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Comments

Richard Deeming 25-Feb-20 10:34am

catch (Exception ex)
{
    throw ex;
}

Don't do that! You've just thrown away the stack trace of the exception, making it much harder to work out where it was thrown from.

If you really want to re-throw an exception, just use throw; instead of throw ex;:

catch (Exception)
{
    throw;
}

But in this case, since you're not doing anything other than rethrowing the exception, there's no point catching it in the first place. Just remove the try..catch block, and let the exception propagate normally.

Richard Deeming 25-Feb-20 10:36am

If you're using Entity Framework Core, you might want to set up a global filter to hide soft-deleted entities:
Global Query Filters - EF Core | Microsoft Docs[^]

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phil.o · Answer 1 · 2020-02-22T23:03:00

Solution 1

You can test for T instead:

C#

public virtual IQueryable<T> GetAll()
{
   try
   {
      return (T is IAuditableEntity)
         ? dbSet.Where(x => !((IAuditableEntity)x).IsDeleted)
         : dbSet.All();
   }
   catch (Exception ex)
   {
      // Here you should do something with the exception (log it for example, or display its details).
      // If you rethrow it, it will be as if you never caught it in the first place.
   }
}

Posted 22-Feb-20 23:03pm

phil.o

Updated 23-Feb-20 6:20am

v2

Comments

Maciej Los 23-Feb-20 12:06pm

5ed!
BTW: do not forget to add x=> into Where statement.

phil.o 23-Feb-20 12:19pm

Corrected. Thanks Maciej :)