Variants.VarCheckEmpty Function

Raises an exception if a specified variant's value is Unassigned.

Pascal

procedure VarCheckEmpty(const V: Variant);

C++

VarCheckEmpty(const Variant V);

File

Variants

Description

Call VarCheckEmpty when your code requires that a System::Variant have a value, and you want to raise an exception if it doesn't. VarCheckEmpty checks whether the System::Variant specified by V has a value of Unassigned. If so, it raises an EVariantTypeMismatchError exception.

To check whether the System::Variant is Unassigned without raising an exception, use the VarIsEmpty function instead. To check whether the System::Variant's value is undefined, use the VarIsClear function instead.

Note: Do not confuse an Unassigned variant with a System::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.