? ? ? ?
textEdit30.Text = ReadValue<int>(() => plc.ReadInt32("DB57.DBD16"), ref _last_num).ToString();

// 通用讀取方法（支持所有值類型）
private T ReadValue<T>(Func<OperateResult<T>> readFunc, ref T lastValue) where T : struct
{
try
{
OperateResult<T> result = readFunc();
if (result != null && result.IsSuccess)
{
lastValue = result.Content;
return result.Content;
}
return lastValue;
}
catch
{
return lastValue;
}
}