Question

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Programmatically determining space available from UNC Path

I’m trying to find a function that I can call from C# to retrieve that information.
This is what I have tried so far:

String folder = "z:\myfolder"; // It works
folder = "\\mycomputer\myfolder"; // It doesn't work

System.IO.DriveInfo drive = new System.IO.DriveInfo(folder);
System.IO.DriveInfo a = new System.IO.DriveInfo(drive.Name);
long HDPercentageUsed = 100 - (100 * a.AvailableFreeSpace / a.TotalSize);

This works ok, but only if I pass a drive letter. Is there a way of retrieving the free space by passing a whole path?

Answer 1

Try to use the winapi function GetDiskFreeSpaceEx:

[DllImport("kernel32.dll", SetLastError=true, CharSet=CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool GetDiskFreeSpaceEx(string lpDirectoryName,
   out ulong lpFreeBytesAvailable,
   out ulong lpTotalNumberOfBytes,
   out ulong lpTotalNumberOfFreeBytes);

ulong FreeBytesAvailable;
ulong TotalNumberOfBytes;
ulong TotalNumberOfFreeBytes;

bool success = GetDiskFreeSpaceEx(@"\\mycomputer\myfolder",
                                  out FreeBytesAvailable,
                                  out TotalNumberOfBytes,
                                  out TotalNumberOfFreeBytes);
if(!success)
    throw new System.ComponentModel.Win32Exception();

Console.WriteLine("Free Bytes Available:      {0,15:D}", FreeBytesAvailable);
Console.WriteLine("Total Number Of Bytes:     {0,15:D}", TotalNumberOfBytes);
Console.WriteLine("Total Number Of FreeBytes: {0,15:D}", TotalNumberOfFreeBytes);