Expression Editor

An Expression is ultimately just a human-readable string and can be written by hand.

However at run-time Expressions are created using AdapTable's Expression Editor.

This visual has a number of useful features including:

  • Drag n Drop of Columns into the Editor

  • Lists all available functions in a dropdown so they can be immediately applied in the Editor

    note

    This list will include any custom functions provided at design-time

  • Provides common operators as buttons above the Editor

  • Ensures that the functions and operators are suitable for the type of Expression being created (e.g. Observable, Scalar etc)

  • Shows existing Named Queries in a list so they can be dragged into the Editor when using QUERY function

  • Displays a row of data from the Grid organised by Column for scenario analysis

    note

    By default the data is taken from the first row of the Grid, but it can be edited by the user in order to try out different scenarios

  • Highlights the return value of the Expression

  • Context sensitive Support / Help for each available function - the Editor explains what the function does, shows its definition and provides an example

  • Links to this Help Site for more detailed information on writing Expressions and the different Query options

    tip

    Set showDocumentationLinks to false in User Interface Options to turn this off

  • Displays a warning - and prevents the user from continuing - if the Expression is not valid

  • Provides a 2nd text area if the WHERE clause is selected (in Observable and Aggregation Expressions)