修改日期后如何读取文件？ [英] How to read file when its date modified is change?

问题描述

大家好，

我有一个文件夹，里面有一个csv文件。我想在修改或更新时读取此文件，我想创建等待文件更新的循环，当文件更新，即其修改日期更改时，快速读取该文件。再等一下。



这可能吗？



我写了下面的代码，但它不能正常工作。纠正我。谢谢。

 私人  void  button1_Click（ object  sender，EventArgs e）
 {
  for （ int  p =  0 ; p >  =  0 ; p ++）
 {
 DateTime dt = File.GetLastWriteTime（filepath）; 
 DateTime date = File.GetCreationTime（filepath）; 
 
  if （File.Exists（filepath））
 {
  if （date！= dt）
 {
 task（）; 
} 
} 
} 
} 
 
  public   void  task（）
 {
  using （FileStream fs =  new  FileStream（filepath，FileMode.Open，FileAccess.Read））
 {
  using （StreamReader sr =  new  StreamReader（fs））
 {
  string  [] line = sr.ReadLine（）。Split （' ，'）; 
 textBox1.Text =  文件更新 + Environment.NewLine; 
} 
} 
} 
 

解决方案

已有机制到位为此，称为 FileSystemWatcher Class [< a href =https://msdn.microsoft.com/en-us/library/system.io.filesystemwatcher(v=vs.110).aspx\"target =_ blanktitle =New Window> ^ ]。



点击链接查看示例。

而不是试图轮询日期我建议你改用FileSystemWatcher并处理Changed事件。请查看此参考，其中包含一个示例： https://msdn.microsoft.com/en-us/ library / system.io.filesystemwatcher [ ^ ]

Hey everyone,
I have one folder which has one csv file. I want to read this file when it is modified or update, I want to create loop that it waits for file update and when file update i.e. its date modified changes , quickly read that file. and again wait.

Is that possible?

I written following code but it does not work proper. Correct me.Thank you.

private void button1_Click(object sender, EventArgs e)
{
    for (int p = 0; p >= 0; p++)
    {
        DateTime dt = File.GetLastWriteTime(filepath);
        DateTime date = File.GetCreationTime(filepath);

        if (File.Exists(filepath))
        {
            if (date != dt)
            {
                task();
            }
        }
    }
}

public void task()
{
    using (FileStream fs = new     FileStream(filepath,FileMode.Open,FileAccess.Read))
    {
        using (StreamReader sr = new StreamReader(fs))
        {
            string[] line = sr.ReadLine().Split(',');
          textBox1.Text = "File update"+ Environment.NewLine;
        }
    }
}

解决方案

There is already a mechanism in place for this, called the FileSystemWatcher Class[^].

Follow the link and have a look at the examples.

Instead of attempting to poll the date I suggest you use a FileSystemWatcher instead and handle the "Changed" event. Check this reference which includes an example: https://msdn.microsoft.com/en-us/library/system.io.filesystemwatcher[^]

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