Finding out total and free disk space in .NET

Question

I am trying to find a way to determine the total and available disk space in an arbitrary folder from a .NET app. By "total disk space" and "available disk space" in a folder I refer to the total and available disk space that this folder would report if you performed a "dir" command on it, that is, the total and available disk space of the logical drive containing that folder.

I am using C#. The method should work both for local and remote folders given as UNC paths (not accessed through mapped drive letters). For example, it should work for:

• C:\Temp
• \\Silfen\Resources\Temp2

I am starting with a DirectoryInfo object, but this seems to have no associated disk space information. The DriveInfo class does, but it won't work with remote folders.

Edit. After some exchanges with you guys, I am considering mapping remote folders as local drives, using DriveInfo to obtain the data, and unmapping again. The problem with this approach is that my app needs to collect the data for over 120 folders a few times a day, every day. I am not sure this would be feasible.

Any ideas? Thanks.

Answer 1

How about this link from MSDN that uses the System.IO.DriveInfo class?

Answer 2

System.IO.DriveInfo works fine. I'm attached to two separate Netware servers, with several drives mapped.

Here's for the local C: drive:

Drive C:\
  File type: Fixed
  Volume label: Drive C
  File system: NTFS
  Available space to current user:   158558248960 bytes
  Total available space:             158558248960 bytes
  Total size of drive:               249884004352 bytes

Here's the output for one of the network drives:

Drive F:\
  File type: Network
  Volume label: SYS
  File system: NWFS
  Available space to current user:     1840656384 bytes
  Total available space:               1840656384 bytes
  Total size of drive:                 4124475392 bytes

I used the following code, directly from the MSDN docs on DriveInfo:

using System;
using System.IO;

class Test
{
    public static void Main()
    {
        DriveInfo[] allDrives = DriveInfo.GetDrives();

        foreach (DriveInfo d in allDrives)
        {
            Console.WriteLine("Drive {0}", d.Name);
            Console.WriteLine("  File type: {0}", d.DriveType);
            if (d.IsReady == true)
            {
                Console.WriteLine("  Volume label: {0}", d.VolumeLabel);
                Console.WriteLine("  File system: {0}", d.DriveFormat);
                Console.WriteLine(
                    "  Available space to current user:{0, 15} bytes", 
                    d.AvailableFreeSpace);

                Console.WriteLine(
                    "  Total available space:          {0, 15} bytes",
                    d.TotalFreeSpace);

                Console.WriteLine(
                    "  Total size of drive:            {0, 15} bytes ",
                    d.TotalSize);
            }
        }
    }
}

Answer 3

I'm pretty sure this is impossible. In windows explorer, if I try to get the folder properties of a UNC directory, it gives me nothing as far as available space. Used/Available space is a characteristic of drives, not folders, and UNC shares are treated as just folders.

you have to either:
- Map a drive
- Run something on the remote machine to check disk space.

You could also run into problems with something like Distributed file system, in which a UNC/Mapped share is NOT tied to any specific drive, so there youd have to actually sum up several drives.

And what about user quotas? The drive may not be full, but the account you are using to write to that folder may have hit its limit.

Answer 4

This may not be what you want, but I'm trying to help.

public static string DriveSizeAvailable(string path)
{
    long count = 0;
    byte toWrite = 1;
    try
    {
        using (StreamWriter writer = new StreamWriter(path))
        {
            while (true)
            {
                writer.Write(toWrite);
                count++;
            }
        }
    }
    catch (IOException)
    {                
    }

    return string.Format("There used to be {0} bytes available on drive {1}.", count, path);
}

public static string DriveSizeTotal(string path)
{
    DeleteAllFiles(path);
    int sizeAvailable = GetAvailableSize(path);
    return string.Format("Drive {0} will hold a total of {1} bytes.", path, sizeAvailable);
}

Answer 5

You can use GetDiskFreeSpaceEx from kernel32.dll which works with UNC-paths and drives. All you need to do is include a DllImport (see link for an example).