如何在不使用循环的情况下跳过在C＃中读取文本文件 [英] How to skip reading text file in C# without using looping

问题描述

如何跳过阅读日志/文本文件行。假设今天我的日志文件有1000个行。我已经完全读完了。所以我需要保留该行不作为书签，我也能够获得该行。第二天，我的日志文件发生了变化，并添加了2000个没有行。所以我不想从头开始阅读它需要从1001到2000读取它。所以如何在不使用任何循环的情况下这样做，因为如果我使用循环然后它再次从头到尾阅读。请帮帮我。

How to skip reading log/text files line. Suppose today my log file having 1000 nos of line. I have read it completely already. So i need to keep that line no as bookmarks and i am able to get that line no as well. And next day my log file change and added 2000 no of lines. So i don't want to read it from start i need to read it from 1001 to 2000. So how to do that without using any looping because if i am using looping then its again reading from start to end. Please help me on this.

推荐答案

您可以使用：

You can use this:

var lines = File.ReadLines(ofd.FileName);
foreach (string line in lines.Skip(8))
    Trace.WriteLine(line);

Because the File.ReadLines returns an IEnumerable<string>, the lines are only loaded when iterated.

Also check File.ReadLines Method http://msdn.microsoft.com/en-us/library/dd383503.aspx

快乐编码小时; _）

Happy coding Hours ;_)

解决方案1：

在阅读之前重命名日志文件，例如通过在文件名中添加日期，然后阅读它。然后，新条目将记录到新的空日志文件中。这样你就不必跟踪任何东西了。



解决方案2：

阅读日志文件时你可能会使用StreamReader并调用ReadLine（）在循环中反复出现？您可以通过StreamReader.BaseStream.Position获取文件中StreamReader的字节位置。我并不是100％确定这与最后一行的读取完全匹配，但如果不匹配则会非常接近。将该位置保存在某个位置 - 在额外的文件或数据库中 - 当您下次打开日志文件时，在开始ReadLine（）之前在该位置前寻找BaseStream。

Solution 1:
Rename the log file before you read it, e.g. by adding the date into the filename, and then read it. The new entries then get logged into a new empty log file. That way you won't have to track anything.

Solution 2:
When reading the log file you probably use a StreamReader and call ReadLine() repeatedly in a loop? You can get the byte-position of the StreamReader in the file via StreamReader.BaseStream.Position. I'm not 100% sure that this matches the end of the last line read exactly but if it doesn't it will be "very close". Save that position somewhere - in an extra file or in a database - and when you open the logfile the next time, seek the BaseStream ahead to that position before starting to ReadLine().

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