THotPDF.SetLoadedFormFieldValueByIndex Method

Sets the current value of an AcroForm form field in the loaded PDF document by field index

Declaration

procedure SetLoadedFormFieldValueByIndex(FieldIndex: Integer; const AValue: AnsiString);

HPDFDoc

Name	Purpose
`FieldIndex`	Zero-based index of the target field in the AcroForm field array
`AValue`	The new value string to write to the V entry of the form field

对复选框字段，AValue 应为导出值（Export Value）或 Off，而非 true / false
After setting the value, the appearance stream (Appearance Stream) of the field may need to be synchronised, otherwise some readers will still display the old value before saving
Changes must be saved before they can be written to the output file