How to implement IModelCacheKeyFactory in EF Core
There actually have demo project in docs https://github.com/aspnet/EntityFramework.Docs/tree/master/samples/core/DynamicModel adding post for convinience !
Here is an example.
Derived DbContext that replaces it's ModelCacheKey (and factory) with a Custom one.
class MyDbContext : DbContext
{
public MyDbContext(string schema)
{
Schema = schema;
}
public string Schema { get; }
protected override void OnConfiguring(DbContextOptionsBuilder options)
=> options
.UseSqlServer("...")
.ReplaceService<IModelCacheKeyFactory, MyModelCacheKeyFactory>();
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.HasDefaultSchema(Schema);
// ...
}
}
The factory that creates the Context with a specific key.
class MyModelCacheKeyFactory : IModelCacheKeyFactory
{
public object Create(DbContext context)
=> new MyModelCacheKey(context);
}
The custom ModelCacheKey per context.
class MyModelCacheKey : ModelCacheKey
{
string _schema;
public MyModelCacheKey(DbContext context)
: base(context)
{
_schema = (context as MyDbContext)?.Schema;
}
protected override bool Equals(ModelCacheKey other)
=> base.Equals(other)
&& (other as MyModelCacheKey)?._schema == _schema;
public override int GetHashCode()
{
var hashCode = base.GetHashCode() * 397;
if (_schema != null)
{
hashCode ^= _schema.GetHashCode();
}
return hashCode;
}
}