Algebra Supported In Expressions Filters in WPF Grouping

24 Feb 2016 / 2 minutes to read

Expressions can be any well-formed algebraic combination of the following:

  • Property (column) names enclosed with square brackets []
  • Numerical constants and literals
  • Algebraic and logical operators

The computations are performed as listed below, with level one operations done first.

  • *, /: multiplication, division
  • +, -: addition, subtraction
  • <, >, =, <=, >=, <>: less than, greater than, equal, less than or equal, greater than or equal, not equal
  • match, like, in, between
  • or, and, or

NOTE

  1. Alpha constants used with match and like should be enclosed in apostrophes (‘).
  2. Logical operators return “1”, if the logical expression is True and return “0”, if the logical expression is False.

Given below is some more information on special logical operators:

  • Match-Returns 1 if there is any occurrence of the right-hand argument in the left-hand argument.

Example

[CompanyName] match ‘RTR’ returns 0 for any record whose CompanyName field does not contain RTR anywhere in the string.

  • Like-Checks if the field starts exactly as specified in the right-hand argument.

Example

[CompanyName] like ‘RTR’ returns 1 for any record whose CompanyName field is exactly ‘RTR’. You can use an asterisk as a wildcard. [CompanyName] like ‘RTR’ returns 1 for any record whose CompanyName field starts with ‘RTR’. [CompanyName] like ‘RTR’ returns 1 for any record whose CompanyName field ends with ‘RTR’.

  • In-Checks if the field value is any of the values listed in the right-hand operand. The collection of items used as the right-hand should be separated by commas and enclosed within braces({ }).

Example

[code] in {1,10,21}, returns 1 for any record whose code field contains 1 or 10 or 21. [CompanyName] in {RTR,MAS} returns 1 for any record whose CompanyName field is RTR or MAS.

Note that spaces that are significant in the list, i.e. {RTR,MAS} is not the same as {RTR, MAS}.

  • Between-Checks if a date field value between the two values is listed in the right-hand operand.

Example

[date] between {2/25/2004, 3/2/2004} returns 1 for any record whose date field is greater than or equal to 2/25/2004 and less than 3/2/2004. To represent the current date, use the token TODAY. To represent DateTime.MinValue, leave the first argument empty. To represent DateTime.MaxValue, leave the second argument empty.

Custom Functions

Essential Grouping lets you add custom functions to your code that can then be used in expressions.

Following are the limitations on the use of custom functions:

  • You cannot use custom functions in algebraic expressions.
  • They must be used stand-alone in a simple expression that consists of only the function name and its argument list.
  • The argument list can be any number of arguments separated by a delimiter.