.Filter<T>(filter)

Applies a complete Filter (where → order → page → select) to a query.

Signature

public static IQueryable<T> Filter<T>(this IQueryable<T> query, Filter filter)
    where T : class, new()

Parameter	Type	Description
`filter`	`Filter`	Composition object — `ConditionGroup`, `Selects`, `Orders`, `Page`

Composition order

The pipeline is applied in this order: where → order → page → select.

Warning

Ordering and pagination are applied on the strongly-typed IQueryable<T> before the select projection so that original field names referenced in orders always resolve against the original entity type T, regardless of which fields are projected.

Validations

ConditionGroup (if provided) is validated as in .Where<T>.
Selects (if provided) is validated as in .Select<T>.
Orders (if provided): each Field must be non-empty and valid on T.
Page (if provided): both PageNumber and PageSize must be > 0.
Because select uses .Select<T>, T must have a parameterless constructor.

Returns

IQueryable<T> — composed query. You can chain further LINQ operators or call ToList() / ToListAsync() to materialize.

Example

var filter = new Filter
{
    ConditionGroup = new ConditionGroup
    {
        Connector = Connector.And,
        Conditions = new List<Condition>
        {
            new Condition { Sort = 1, Field = "Price",         DataType = DataType.Number, Operator = Operator.GreaterThan, Values = new List<object> { 50 } },
            new Condition { Sort = 2, Field = "Category.Name", DataType = DataType.Text,   Operator = Operator.IEqual,      Values = new List<object> { "electronics" } }
        }
    },
    Selects = new List<string> { "Id", "Name", "Price", "Category.Name" },
    Orders  = new List<OrderBy> { new OrderBy { Sort = 1, Field = "Price", Direction = Direction.Descending } },
    Page    = new PageBy { PageNumber = 1, PageSize = 10 }
};

IQueryable<Product> query = dbContext.Products.Filter(filter);