System.Variants.VarCheckEmpty
Delphi
procedure VarCheckEmpty(const V: Variant);
C++
extern DELPHI_PACKAGE void __fastcall VarCheckEmpty(const System::Variant &V);
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
procedure function |
public | System.Variants.pas System.Variants.hpp |
System.Variants | System.Variants |
Description
Raises an exception if a specified variant's value is Unassigned.
Call VarCheckEmpty when your code requires that a Variant have a value, and you want to raise an exception if it doesn't. VarCheckEmpty checks whether the Variant specified by V has a value of Unassigned. If so, it raises an EVariantTypeMismatchError exception.
To check whether the Variant is Unassigned without raising an exception, use the VarIsEmpty function instead. To check whether the Variant's value is undefined, use the VarIsClear function instead.
Note: Do not confuse an Unassigned variant with a Variant whose value is Null. A Null variant is still assigned, but has the value Null. Unlike unassigned variants, Null variants can be used in expressions and can be converted to other types of variants.