public static Expression <Func <T, bool> > BuildPrimaryKeyExpression <T, TKey>(this IMetaDataProvider repository, TKey id)
where T : class
{
var primaryKey = repository.GetPrimaryKey <T>().First();
var parameter = Expression.Parameter(typeof(T));
var left = Expression.Convert(Expression.PropertyOrField(parameter, primaryKey), typeof(TKey));
var body = Expression.Equal(left, Expression.Constant(id, typeof(TKey)));
var predicate = Expression.Lambda <Func <T, bool> >(body, parameter);
return((Expression <Func <T, bool> >)Evaluator.PartialEval(predicate));
}
public static Expression <Func <T, bool> > BuildPrimaryKeyExpression <T, ID>(this IMetaDataProvider repository, ID id)
where T : class
{
var primaryKey = repository.GetPrimaryKey <T>().First();
var parameter = Expression.Parameter(typeof(T));
var body = Expression.Convert(Expression.PropertyOrField(parameter, primaryKey), typeof(ID));
var idSelector = Expression.Lambda <Func <T, ID> >(body, parameter);
var predicate = idSelector.BuildOrExpression(new[] { id });
return(predicate);
}
IEnumerable <T> IBulkOperationsProvider.GetById <T, TKey>(IEnumerable <TKey> ids)
{
if (typeof(OID).IsAssignableFrom(typeof(TKey)))
{
return(ids.Select(id => (T)_context.Session.GetObjectFromId((OID)id)));
}
var primaryKey = _metaDataProvider.GetPrimaryKey <T>().First();
var parameter = Expression.Parameter(typeof(T));
var body = Expression.Convert(Expression.PropertyOrField(parameter, primaryKey), typeof(TKey));
var idSelector = Expression.Lambda <Func <T, TKey> >(body, parameter);
var predicate = idSelector.BuildOrExpression(ids.ToList());
return(All <T>().Where(predicate).AsEnumerable());
}
public IEnumerable <T> GetById <T, ID>(IList <ID> ids) where T : class
{
if (typeof(OID).IsAssignableFrom(typeof(T)))
{
return(ids.Select(id => (T)_context.Session.GetObjectFromId((OID)id)));
}
else
{
var primaryKey = _metaDataProvider.GetPrimaryKey <T>().First();
var parameter = Expression.Parameter(typeof(T));
var body = Expression.Convert(Expression.PropertyOrField(parameter, primaryKey), typeof(ID));
var idSelector = Expression.Lambda <Func <T, ID> >(body, parameter);
var predicate = idSelector.BuildOrExpression <T, ID>(ids);
return(this.All <T>().Where(predicate).AsEnumerable());
}
}
public static Expression <Func <T, bool> > BuildPrimaryKeyExpression <T>(this IMetaDataProvider repository, T entity)
where T : class
{
var primaryKeyValue = repository.GetPrimaryKeyValue(entity);
var primaryKey = repository.GetPrimaryKey <T>();
var values = primaryKey.Zip(primaryKeyValue, Tuple.Create).ToArray();
Expression <Func <T, bool> > predicate = null;
foreach (var value in values)
{
var parameter = Expression.Parameter(typeof(T));
var left = Expression.Convert(Expression.PropertyOrField(parameter, value.Item1), value.Item2.GetType());
var body = Expression.Equal(left, Expression.Constant(value.Item2));
predicate = predicate == null?Expression.Lambda <Func <T, bool> >(body, parameter) : predicate.And(Expression.Lambda <Func <T, bool> >(body, parameter));
}
return((Expression <Func <T, bool> >)Evaluator.PartialEval(predicate));
}