This content originally appeared on DEV Community and was authored by Karen Payne
There are times when the working with files and folders a developer runs into unusual task that for some may be difficult to figure out or takes too much time to code.
Bookmark this article for methods for working with files and folders and overtime more code samples will be added as there are many more to come. What will not be added are methods easy to find on the Internet.
Requires
- Microsoft Visual Studio 2022 or higher
- .NET Core 7 or higher
Is folder or file
When traversing a folder a developer may want to know if an item is a file or folder.
The following method will, if successful indicate if an item is a file or folder and if the item does not exists the method returns false.
public static (bool isFolder, bool success) IsFileOrFolder(string path)
{
try
{
var attr = File.GetAttributes(path);
return attr.HasFlag(FileAttributes.Directory) ? (true, true)! : (false, true)!;
}
catch (FileNotFoundException)
{
return (false, false);
}
}
In the following example, LogFile folder exists, its created using a msbuild task, Log does not exists but TextFile1.txt does exists.
static void Main(string[] args)
{
var items = new List<string>
{
Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "LogFiles"),
Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Log"),
Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TextFile1.txt")
};
foreach (var item in items)
{
var (isFolder, success) = FileHelpers.IsFileOrFolder(item);
if (success)
{
AnsiConsole.MarkupLine($"{item}");
AnsiConsole.MarkupLine($"\tIs folder {isFolder}");
}
else
{
AnsiConsole.MarkupLine($"[white]{item}[/] [red]not found[/]");
}
}
Console.ReadLine();
}
Is file locked
The following method detects if a file is locked when a file is opened with the attribute FileShare.None. Typical example, a developer does not close an Excel file properly or has the Excel file open outside the project.
This will not work if a file is open in shared mode.
public static async Task<bool> CanReadFile(string fileName)
{
static bool IsFileLocked(Exception exception)
{
var errorCode = Marshal.GetHRForException(exception) & ((1 << 16) - 1);
return errorCode is ErrorSharingViolation or ErrorLockViolation;
}
try
{
await using var fileStream = File.Open(fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.None);
if (fileStream != null)
{
fileStream.Close();
}
}
catch (IOException ex)
{
if (IsFileLocked(ex))
{
return false;
}
}
await Task.Delay(50);
return true;
}
See the project IsFileLockedSample for an interactive example with an Excel file and a text file.
Natural sort file names
The following methods will sort file names that end in numbers or an array or list with strings ending in numbers the same as in Windows Explorer.
public class NaturalStringComparer : Comparer<string>
{
[DllImport("Shlwapi.dll", CharSet = CharSet.Unicode)]
private static extern int StrCmpLogicalW(string x, string y);
public override int Compare(string x, string y)
=> StrCmpLogicalW(x, y);
}
Example with a list of unsorted strings.
using System.Runtime.CompilerServices;
using Spectre.Console;
using static HelperLibrary.FileHelpers;
namespace NaturalSortSample;
internal class Program
{
static void Main(string[] args)
{
StandardSortSample();
NaturalSortSample();
Console.ReadLine();
}
private static void NaturalSortSample()
{
Print("Natural sort");
var fileNames = FileNames();
fileNames.Sort(new NaturalStringComparer());
foreach (var item in fileNames)
{
Console.WriteLine(item);
}
}
private static void StandardSortSample()
{
Print("Standard sort");
var fileNames = FileNames();
foreach (var item in fileNames)
{
Console.WriteLine(item);
}
}
private static List<string> FileNames() =>
new()
{
"Example12.txt", "Example2.txt", "Example3.txt", "Example4.txt",
"Example5.txt", "Example6.txt", "Example7.txt", "Example8.txt",
"Example9.txt", "Example10.txt", "Example11.txt", "Example1.txt",
"Example13.txt", "Example14.txt", "Example15.txt", "Example16.txt",
"Example17.txt", "Example18.txt", "Example19.txt", "Example20.txt"
};
private static void Print(string text)
{
AnsiConsole.MarkupLine($"[yellow]{text}[/]");
}
[ModuleInitializer]
public static void Init()
{
Console.Title = "Code sample";
W.SetConsoleWindowPosition(W.AnchorWindow.Center);
}
}
Globbing
File globbing can in specific cases allow a developer to fine tune files that are looking for in a folder or folders.
Provides
- Inclusion of files via patterns
- Exclusion of file via patterns
Base patterns
| Value | Description |
|---|---|
| *.txt | All files with .txt file extension. |
| *.* | All files with an extension |
| * | All files in top-level directory. |
| .* | File names beginning with '.'. |
| *word* | All files with 'word' in the filename. |
| readme.* | All files named 'readme' with any file extension. |
| styles/*.css | All files with extension '.css' in the directory 'styles/'. |
| scripts/*/* | All files in 'scripts/' or one level of subdirectory under 'scripts/'. |
| images*/* | All files in a folder with name that is or begins with 'images'. |
| **/* | All files in any subdirectory. |
| dir/**/* | All files in any subdirectory under 'dir/'. |
| ../shared/* | All files in a diretory named "shared" at the sibling level to the base directory |
In this project (Razor Pages) the goal is to get all .cs file with several exclusions as per the variable exclude
await GlobbingOperations.Find(path, include, exclude); traverses the path which in this case is the current solution folder and on a match adds the match to a StringBuilder which we return the page and append to the body of the page the results.
public class IndexModel : PageModel
{
public IndexModel()
{
GlobbingOperations.TraverseFileMatch += TraverseFileMatch;
}
[BindProperty]
public StringBuilder Builder { get; set; } = new();
public void OnGet()
{
}
public async Task<PageResult> OnPost()
{
string path = DirectoryHelper.SolutionFolder();
string[] include = { "**/*.cs", "**/*.cshtml" };
string[] exclude =
{
"**/*Assembly*.cs",
"**/*_*.cshtml",
"**/*Designer*.cs",
"**/*.g.i.cs",
"**/*.g.cs",
"**/TemporaryGeneratedFile*.cs"
};
Builder = new StringBuilder();
await GlobbingOperations.Find(path, include, exclude);
return Page();
}
private void TraverseFileMatch(FileMatchItem sender)
{
Log.Information(Path.Combine(sender.Folder, sender.FileName));
Builder.AppendLine(Path.Combine(sender.Folder, sender.FileName));
}
}
Stay tune for more
More useful methods will be added over time.
Source code
Clone the following GitHub repository.
This content originally appeared on DEV Community and was authored by Karen Payne
Karen Payne | Sciencx (2023-04-30T01:49:18+00:00) C# file/folder helpers. Retrieved from https://www.scien.cx/2023/04/30/c-file-folder-helpers/
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