Question

有人可以解释System.Timer对ElapsedEventHandler的作用吗？我不明白这种语法：

private readonly System.Timers.Timer _timer7 = new System.Timers.Timer();
this._timer7.Elapsed += (ElapsedEventHandler) ((A_1, A_2) =>
      {
        this._logger.LoggingOfError("T7-Timeout");
      });

Answer 1

您的问题的代码与以下代码相同：

...
19982
19983
---------------------------------------------------------------------------
InvalidArgumentError                      Traceback (most recent call last)
<ipython-input-26-36305ee0e8ef> in <module>()
----> 1 for i,(label, img) in enumerate(dataset):
      2   print(i)

4 frames
/usr/local/lib/python3.6/dist-packages/six.py in raise_from(value, from_value)

InvalidArgumentError: ValueError: Tensor's shape (7,) is not compatible with supplied shape [48, 48, 1]
Traceback (most recent call last):

  File "/usr/local/lib/python3.6/dist-packages/tensorflow/python/ops/script_ops.py", line 209, in __call__
    ret = func(*args)

  File "/usr/local/lib/python3.6/dist-packages/tensorflow/python/data/ops/dataset_ops.py", line 525, in generator_py_func
    values = next(generator_state.get_iterator(iterator_id))

  File "<ipython-input-25-196a9ac04fc0>", line 5, in img_resize_and_crop_genr
    img.set_shape([side_len, side_len,1])

  File "/usr/local/lib/python3.6/dist-packages/tensorflow/python/framework/ops.py", line 981, in set_shape
    (self.shape, shape))

ValueError: Tensor's shape (7,) is not compatible with supplied shape [48, 48, 1]


     [[{{node PyFunc}}]] [Op:IteratorGetNextSync]

与以下相同：

_timer7.Elapsed += (sender, e) =>
{
  _logger.LoggingOfError("T7-Timeout");
};

您可以在此处获得有关匿名方法的说明：

What are anonymous methods in C#?

Answer 2

System.Timers.Elapsed是ElapsedEventHandler的类型，定义如下：

public delegate void ElapsedEventHandler(object sender, ElapsedEventArgs e);

为delegate注册的_timer7.Elapsed是Lambda Expression（匿名方法）。

A_1是sender，而A_2是e。

因此，将触发_timer7.Elapsed时，将调用带有参数A_1为sender和A_2为e的匿名方法。
这将导致行this._logger.LoggingOfError("T7-Timeout");被执行

设置Elapsed属性时，这是什么语法？

2 个答案: