get_file_system_infos() [2/2]

std::vector< xtd::sptr< xtd::io::file_system_info > > xtd::io::directory_info::get_file_system_infos

(

const xtd::string &

search_pattern

)

const

Retrieves an array of strongly typed FileSystemInfo objects representing the files and subdirectories that match the specified search criteria.

Parameters

search_pattern

The search string to match against the names of directories and files. This parameter can contain a combination of valid literal path and wildcard (* and ?) characters, but it doesn't support regular expressions.

Returns

An array of strongly typed xtd::io::file_system_info entries.

Exceptions

xtd::io::directory_not_found_exception	The specified path is invalid, such as being on an unmapped drive.
xtd::security::security_exception	The caller does not have code access permission to create the directory.

Examples

The following example counts the files and directories that match the specified search pattern.

#include <xtd/xtd>
 
using namespace xtd;
using namespace xtd::io;
 
class program {
public:
  static auto main() {
    try {
      console::write_line("Enter the path to a directory:");
 
      string directory = console::read_line();
 
      console::write_line("Enter a search string (for example *p*):");
 
      string search_string = console::read_line();
 
      // Create a new directory_info object.
      directory_info dir(directory);
 
      if (!dir.exists()) {
        throw directory_not_found_exception("The directory does not exist.", csf_);
      }
 
      // Call the GetFileSystemInfos method.
      std::vector<xtd::sptr<file_system_info>> infos = dir.get_file_system_infos(search_string);
 
      console::write_line("Working...");
 
      // Pass the result to the list_directories_and_files
      // method defined below.
      list_directories_and_files(infos, search_string);
 
      // Display the results to the console.
      console::write_line("Directories: {0}", directories);
      console::write_line("Files: {0}", files);
    } catch (const exception& e) {
      console::write_line(e.message());
    }
  }
 
private:
  static void list_directories_and_files(std::vector<xtd::sptr<file_system_info>> fs_info, const string& search_string) {
    // Iterate through each item.
    for (xtd::sptr<file_system_info> i : fs_info) {
      // Check to see if this is a directory_info object.
      if (is<directory_info>(i)) {
        // Add one to the directory count.
        directories++;
 
        // Cast the object to a directory_info object.
        xtd::sptr<directory_info> d_info = as<directory_info>(i);
 
        // Iterate through all sub-directories.
        list_directories_and_files(d_info->get_file_system_infos(search_string), search_string);
      }
      // Check to see if this is a FileInfo object.
      else if (is<file_info>(i)) {
        // Add one to the file count.
        files++;
      }
    }
  }
 
  inline static long files = 0;
  inline static long directories = 0;
};
 
startup_(program::main);

Remarks

search_pattern can be a combination of literal and wildcard characters, but it doesn't support regular expressions. The following wildcard specifiers are permitted in search_pattern.

Wildcard specifier	Matches
* (asterisk)	Zero or more characters in that position.
? (question mark)	Zero or one character in that position.

Characters other than the wildcard are literal characters. For example, the string "*t" searches for all names in ending with the letter "t". ". The search_pattern string "s*" searches for all names in path beginning with the letter "s".

The xtd::io::directory_info::enumerate_file_system_infos and xtd::io::directory_info::get_file_system_infos methods differ as follows:

• When you use xtd::io::directory_info::enumerate_file_system_infos, you can start enumerating the collection of xtd::io::file_system_info objects before the whole collection is returned.
• When you use xtd::io::directory_info::get_file_system_infos, you must wait for the whole array of xtd::io::file_system_info objects to be returned before you can access the array.

Therefore, when you are working with many files and directories, xtd::io::directory_info::enumerate_file_system_infos can be more efficient.

This method pre-populates the values of the following xtd::io::file_system_info properties:

• xtd::io::file_system_info::attributes
• xtd::io::file_system_info::creation_time
• xtd::io::file_system_info::last_access_time
• xtd::io::file_system_info::last_write_time
• xtd::io::file_system_info::size