As much Value as AsValue can be used to obtain a control’s value, although they can also be used to assign a value to a concrete control, however, you will notice the differences between them upon obtaining the values.

When you use Value in order to know the value, this property could return a NULL value (when the control doesn’t contain anything), nevertheless, when you are using AsValue, this property will never return a NULL, for instance:

  • A DataType control dtyString without value return:
    • Value = NULL
    • AsValue = ”
  • A DataType control dtyInteger without value returns:
    • Value = NULL
    • AsValue = 0

Later you could use the JfVarIsNull function (JfUtil unit) to know if Value is/isn’t NULL.