C#中，如何获得或设置文件属性（Attributes）

When testing for a single specific attribute, you need to use bitwise arithmetic. For example,consider the following faulty code:

 

if (myFile.Attributes == FileAttributes.ReadOnly)
...{ ... }

 

This test succeeds only if the read-only attribute is the only attribute for the current file. This israrely the case. If you want to successfully check whether the file is read-only, you need this codeinstead:

 

if ((myFile.Attributes & FileAttributes.ReadOnly) != 0)...{ ... }

When setting an attribute, you must also use bitwise arithmetic. In this case, you need to ensure
that you don’t inadvertently wipe out the other attributes that are already set.

 

// This sets the read-only attribute (and keeps all others as is).
myFile.Attributes = myFile.Attributes | FileAttributes.ReadOnly;

// This removes the read-only attribute (and keeps all others as is).
myFile.Attributes = myFile.Attributes & ~FileAttributes.ReadOnly;