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AsFloat0

property AsFloat0: Double read write;

Example​

procedure ScriptEvent(var Value: variant);
var
  Text: TJSONString;
  Item: TJSONValue;
begin
  Text := TJSONString.Create;
  try
    Item := Text;
    Item.AsString := 'not-a-number';
    Value := Item.AsFloat0;  // 0.0; conversion failure is suppressed.
  finally
    Text.Free;
  end;
end;

Usage​

AsFloat0 reads a locale-sensitive floating value with zero fallback while retaining the strict AsDouble writer.

Additional Technical Info​

The reader returns 0.0 when IsNull is true. Otherwise it calls locale-sensitive StrToFloatDef(DoGetAsString, 0.0). Any text conversion failure becomes 0.0 rather than an exception. Because it calls the virtual raw getter without checking ValueType, Booleans, malformed Strings, and even serialized objects/arrays normally collapse to zero.

This convenience loses information: valid zero, null, malformed text, incompatible type and some locale mismatches all have the same result. Check IsNull, ValueType and/or use strict AsDouble when validation or diagnostics matter.

The writer is not a defaulting writer. It is the exact strict AsDouble writer: FloatToStr uses current global locale settings, then the concrete value class parses/stores that text or raises. The getter and setter are therefore asymmetric. The no-format-settings conversion path is not locale-invariant and is not thread-safe under concurrent changes to global format settings.

External references

Created 2026-07-15