问题
I was reading File.AppendAllText method from msdn
http://msdn.microsoft.com/en-us/library/ms143356.aspx
I saw they have listed FileNotFoundException to possible exceptions list for the method but according to there description about method on the same page
Opens a file, appends the specified string to the file, and then closes the file. If the file does not exist, this method creates a file, writes the specified string to the file, then closes the file.
this part
If the file does not exist, this method creates a file
it seems this exception can never be thrown for this method.
回答1:
If you take a look at (say) Mono's implementation (which is compatible with Microsoft's), all File.AppendAllText ends up doing (argument checks aside) is creating a StreamWriter with your path and calling a Write on that object.
Neither the used constructor nor the method are listed anywhere to throw a FileNotFoundException, as far as I can tell, so it might be a documentation error.
回答2:
This thread may be old, but the correct answer given above by One-man-crew was ignored by others. The fact is that the FileNotFoundException is not a typo error. It exists, and I get it. The reason is in the exception message as follows: "Could not find part of the path". As described, the File.AppendAllText will open the file if it does not exist, but it must have a valid path.
来源：https://stackoverflow.com/questions/14626728/filenotfoundexception-in-file-appendalltext