Icon IsNull Property

property IsNull: Boolean

Usage

Use the IsNull property to discover if the value of the parameter is NULL, indicating the value of a blank field. NULL values can arise in the following ways:

   Assigning the value of another, NULL, parameter.
   Assigning the value of a blank TField object using the AssignFieldValue method.
   Calling the Clear method.

Information NULL parameters are not the same as unbound parameters. Unbound parameters have not had a value assigned. NULL parameters have a NULL value. NULL parameters may be bound or unbound.
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