---
title: Filter and sort
slug: commerce-connect-15/docs/filter-and-sort
docTags: 
createdAt: 2026-07-30T20:34:45.000Z
---

Business Foundation (BF) has a unified object model for filtering and sorting rows and entity objects. The filter is analogous to the SQL **WHERE** clause. The filter contains a *filter pattern*, which evaluates to a Boolean value and is tested for each element in the collection. Elements that fail the test are omitted from the result collection.

The sorting is analogous to the SQL **ORDER BY** clause. The sorting element contains field name and direction.

:::hint{type="info"}
**Note**
By default, the top block is **AND**.
:::

Classes in this topic are available in the `Mediachase.BusinessFoundation.Data` namespace.

## Create simple filters

**Example:** Returns elements where the key is 1:

```csharp
FilterElement filter = FilterElement.EqualElement("Key", "1");
```

**Example:** Returns elements where `key` contains keyword:

```csharp
FilterElement filter = new FilterElement("Key", FilterElementType.Contains, keyword)
```

**Example:** Returns elements where `StartDate` is between two days:

```csharp
FilterElement filter = new IntervalFilterElement("StartDate", from, to)
```

## Use logical blocks

You can create logical blocks using the `OrBlockFilterElement` and `AndBlockFilterElement` classes.

**Example:** Return elements where `Extension` is `txt` or empty string:

```csharp
OrBlockFilterElement orBlock = new OrBlockFilterElement(
       FilterElement.EqualElement("Extension", "txt"),
       FilterElement.EqualElement("Extension", string.Empty));
```

## Templates

BF supports template values in the filter and sorting expressions, using the template directives in the following section. Use the `ResolveAll` and `Resolve` methods to resolve custom template strings in your code.

**Template Directive:**

`{_TemplateSource_:_TemplateValue_}`

For example, the string `:{DateTime:Today}` is converted to the current date.

To register a new template source, call `AddSource` of the `TemplateResolver` class, passing template source name and template source class.

`DateTimeTemplateSource`, included in BF, can convert template value strings to real date time.

**Supported template values** – `Today`, `TodayStart`, `Yesterday`, `YesterdayStart`, `ThisWeek`, `ThisWeekStart`, `ThisMonth`, `ThisMonthStart`, `LastMonth`, `LastMonthStart`, `ThisYear`, `ThisYearStart`, `LastYear`, `LastYearStart`, `TodayEnd`, `YesterdayEnd`, `ThisWeekEnd`, `LastWeekEnd`, `ThisMonthEnd`, `ThisYearEnd`, `LastMonthEnd`, `ThisYearEnd`, `LastYearEnd`.

To create a custom template source, create a class that implements the `ITemplateSource` interface. Implement the `GetValue` method.

## Use template value in filters

**Example:** Using template value in filter expression:

```csharp
IntervalFilterElement filter = new IntervalFilterElement("StartDate",
  string.Format("{{DateTime:{0}Start}}", "Today"),
  string.Format("{{DateTime:{0}End}}", "Today"));
  filter.ValueIsTemplate = true;
```

## Sort

Use the `SortingElement` class to define sorting element.

**Example:** Sorting output collection by `IsProject` columns, ascending:

```csharp
SortingElement sorting = new SortingElement("IsProject", SortingElementType.Asc);
```