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TvxVariable

TvxVariable = class(TPersistent)

Example​

procedure ScriptEvent(var Value: Variant);
var WorkVar: TvxVariable;
begin
  WorkVar := Locals['WorkValue'];
  WorkVar.AsStringTrim := '  Example  ';
  Value := WorkVar.AsString;
end;

Usage​

TvxVariable stores a named Variant with optional encryption, typed conversion aliases and an optional client dataset.

Additional Technical Info​

TvxVariable is Velox's named mutable Variant container. Variable lists, variable groups, Settings, Locals, Globals and AzureSecrets expose instances with different ownership/lifetime rules.

The object owns a re-entrant monitor, an optional lazily created TvxClientDataSet and an internal Variant. Value, most aliases and dataset create/free operations lock the monitor, but returned datasets and object references remain usable after unlock and are not lifetime-protected.

Value and encryption

Value is the canonical read/write path. When native Encrypted is true, normal Value writes encrypt the string representation and normal reads decrypt it. Component loading/writing has special raw-storage paths. AsString, AsSQL and AsInfo use Value and therefore honour decryption.

Typed numeric/Boolean/date setters write the internal Variant directly, bypassing Value validation and encryption. Their getters also read the raw Variant, so they are unsafe aliases for encrypted variables. This is an implementation quirk, not a general conversion guarantee.

Conversions and data

  • String aliases use Delphi VarToStr; Trim variants remove leading/trailing spaces and control characters.
  • Float/Integer aliases catch failed Variant coercion and return zero; DateTime propagates failed conversion.
  • Boolean accepts Boolean values, nonzero ordinals, or exactly True/true; unsupported types can leave an undefined result.
  • SQL aliases create quoted SQL text, but their setters contain a lossy substring calculation and are not safe round-trip parsers.
  • Data lazily creates a dataset named from Code; FreeData destroys it.

Code's setter locks, but its getter deliberately does not. Treat shared variables as individually synchronized scalar snapshots, not as atomic multi-property records. Do not free list/group-owned variables, and do not retain their datasets across FreeData or owner/cache invalidation.

The runtime importer contains a constructor binding but the compiler registration does not declare Create, and no generated constructor entry exists. Do not rely on constructing this class in Velox scripts.

Created 2026-07-15