Find a specified generic DbSet in a DbContext dynamically when I have an entity
c# code-first dbset entity-framework generics
Question
I have following classes and DbContext:
public class Order:BaseEntity
{
public Number {get; set;}
}
Product:BaseEntity;
{
public Name {get; set;}
}
public class Context : DbContext
{
....
public DbSet<Order> Orders { set; get; }
public DbSet<Product> Products { set; get; }
....
}
I have a list of objects that want to add to my context, too, but I don't know how can I find appropriate generic DbSet according each entity type dynamically.
IList<BaseEntity> list = new List<BaseEntity>();
Order o1 = new Order();
o1.Numner = "Ord1";
list.Add(o1);
Product p1 = new Product();
p1.Name = "Pencil";
list.Add(p1);
Context cntx = new Context();
foreach (BaseEntity entity in list)
{
cntx.Set<?>().Add(entity);
}
How can I do that?
Accepted Answer
DbContext has a method called Set, that you can use to get a non-generic DbSet, such as:
var someDbSet = this.Set(typeof(SomeEntity));
So in your case:
foreach (BaseEntity entity in list)
{
cntx.Set(entity.GetType()).Add(entity);
}
Popular Answer
The question does not specify EF version and the proposed answer does not work anymore for Entity Framework Core (in EF Core, DbContext does not have a non-generic Set method, at least at the date of this answer).
Yet you can still have a working extension method using Jon Skeet's answer to this question. My code is added below for convenience.
Update: Added the generic function call as well returning IQueryable<T> thanks to the comment from Shaddix.
public static IQueryable Set(this DbContext context, Type T)
{
// Get the generic type definition
MethodInfo method = typeof(DbContext).GetMethod(nameof(DbContext.Set), BindingFlags.Public | BindingFlags.Instance);
// Build a method with the specific type argument you're interested in
method = method.MakeGenericMethod(T);
return method.Invoke(context, null) as IQueryable;
}
public static IQueryable<T> Set<T>(this DbContext context)
{
// Get the generic type definition
MethodInfo method = typeof(DbContext).GetMethod(nameof(DbContext.Set), BindingFlags.Public | BindingFlags.Instance);
// Build a method with the specific type argument you're interested in
method = method.MakeGenericMethod(typeof(T));
return method.Invoke(context, null) as IQueryable<T>;
}
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