Member variable Get():postBlock Foundation

A code block may optionally be assigned to the instance variable :postBlock. By default, the value of this instance variable is NIL and is not required by the Get object. During processing of the READ command by ReadModal(), if the :postBlock instance variable of the currently active Get object contains a code block it is evaluated by the function GetPostValidate() prior to the Get object losing input focus. The code block in :postBlock should contain an expression or call a function that accepts one argument (the Get object) and return .T. (true) if the data entered in the Get object's edit buffer is valid, or .F. (false) if it is not. If the code block returns .T., focus is lost on the current Get object and processing continues with the next Get object; otherwise, the focus remains with the current Get object. When using the @...GET command, the expression specified in the VALID or RANGE clause is stored in a code block which is then automatically assigned to the instance variable :postBlock.