对此，没有万无一失的答案。如果你知道任何文本文件只能是ASCII字符（用ASCII，UTF-8或类似的东西编码），那么是的，这将工作...虽然它可能无法捕获所有的非全部字符，文本文件。

但是：

• 任何文本文件都会失败非ASCII文本


• 对于某种格式的文件而言，该文件仍然可能失败，但该文件不包含任何超过128的值。

字节序列{34,87,23,10}是否代表文本或二进制数据？确实无法知道。 你做的任何事情都是启发式的。

I need to read through many files and search for specific text in them. I want to open only text files, i.e., no image, movie, etc. files. I am looking for a way to identify non-text files. Since I will be using a FileStream and doing a byte search, it seems to me I can stop reading and close a file if a byte whose decimal value is greater than 128 is encountered. Does this seem like a good approach?

There's no foolproof answer for this. If you know that any text files will only ever be ASCII characters (and encoded in ASCII, UTF-8 or something similar) then yes, that will work... although it may not catch all non-text files.

However:

• It will fail for any text files using non-ASCII text
• It could still fail for a file which is a valid binary file for some format, but happens not to contain any values above 128.

Does the sequence of bytes { 34, 87, 23, 10 } represent text or binary data? There's simply no way of knowing for sure. Anything you do will be heuristic.