如何获得Variant变量的真正类型

function GetVariantType(const v: variant): string; 
begin 
  case TVarData(v).vType of 
    varEmpty: result := 'Empty'; 
    varNull: result := 'Null'; 
    varSmallInt: result := 'SmallInt'; 
    varInteger: result := 'Integer'; 
    varSingle: result := 'Single'; 
    varDouble: result := 'Double'; 
    varCurrency: result := 'Currency'; 
    varDate: result := 'Date'; 
    varOleStr: result := 'OleStr'; 
    varDispatch: result := 'Dispatch'; 
    varError: result := 'Error'; 
    varBoolean: result := 'Boolean'; 
    varVariant: result := 'Variant'; 
    varUnknown: result := 'Unknown'; 
    varByte: result := 'Byte'; 
    varString: result := 'String'; 
    varTypeMask: result := 'TypeMask'; 
    varArray: result := 'Array'; 
    varByRef: result := 'ByRef'; 
  end; // case 
end;