LMD-Tools Validators Guide

Error Provider Groups

Error Providers Group is a special type of Error Provider component which allows for grouping of several Error Providers which can be then used as one to employ several ways of error indication simultaneously. Error Providers Group is a descendant of TLMDCsutomErrorProvider and implements DisplayError method by sequential calls to DisplayError method of all the Error Providers included in the ErrorProviders collection. ximum of all the values returned by grouped Validators. Error messages from grouped Validators are then dispatched to the Error Providers included into the ErrorProviders collection according to their [MinErrorLevel;MaxErrorLevel] ranges. Validation Group introduces several properties for controlling validation process (see the table below).

As an Error Provider Group is technically an Error Provider, it can be included into another Error Providers Group. Number of levels of such nesting of Error Providers Group is not limited. It provides a flexible way to re-use error-indication sets.

Warning: Loops should be avoided while nesting Error Providers Groups!

Notes: Validation Group component directly supports use of multiple Error Providers with its ErrorProviders collection, so use of Error Provider Group for multiple ways of error indication is not mandatory when using Validation Groups. Another alternative to Error Provider Group is TLMDErrorProvider component which is an aggregate of several Error Providers and supports four ways of error indication.

Properties

Name	Type	Description
ErrorProviders	TLMDErrorProviders	The collection of Error Providers which are available for error indication. TLMDErrorProviders is a descendant of TCollection class, its items are of type TLMDErrorProviderItem which descends from TCollectionItem. The main property of TLMDErrorProviderItem is ErrorProvider of TLMDCustomErrorProvider type which can refer to an Error Provider or an Error Providers Group component.