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AsFloat

property AsFloat: Double read write;

Example​

function GrossWeight(const Data: TvxClientDataSet): Double;
begin
  Result := Data.FieldByName('NetWeight').AsFloat +
    Data.FieldByName('PackagingWeight').AsFloat;
end;

Usage​

AsFloat reads or writes a numeric-compatible field as an IEEE Double, subject to field rounding, scale, range and text-conversion rules.

  • Use AsCurrency or a BCD-aware path when exact decimal scale is a business requirement.
  • Check finite/range expectations before assigning calculated values.
  • Do not rely on machine/locale-dependent string parsing; parse governed external text explicitly before assignment.

Additional Technical Info​

AsFloat asks the runtime field descendant to represent its value as a Delphi Double or to accept a Double assignment.

Source-backed behaviour​

Base TField raises a field-access error. Numeric descendants implement the conversion; integer fields return their integer value as Double and round a Double assignment before range checking, while string fields parse using Delphi numeric conversion and current format settings. Currency/BCD descendants can apply their own scale rules. These paths mean the same script assignment can round, overflow or fail differently according to the runtime field class.

A null compatible numeric field normally reads 0.0; use IsNull to retain null semantics. IEEE Double cannot exactly represent every decimal database value or every 64-bit integer. Assignment goes through dataset write-state, read-only, OnValidate, provider verification and change-event handling.

Official RTL references​

Created 2026-07-15