How can I determine if a remote drive has enough space to write a file using C#?

Question

How can I determine if a remote drive has enough space for me to upload a given file using C# in .Net?

Answer 1

There are two possible solutions.

1. Call the Win32 function GetDiskFreeSpaceEx. Here is a sample program:

   internal static class Win32
   {
       [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
       internal static extern bool GetDiskFreeSpaceEx(string drive, out long freeBytesForUser, out long totalBytes, out long freeBytes);
   
   }
   
   class Program
   {
       static void Main(string[] args)
       {
           long freeBytesForUser;
           long totalBytes;
           long freeBytes;
   
           if (Win32.GetDiskFreeSpaceEx(@"\\prime\cargohold", out freeBytesForUser, out totalBytes, out freeBytes)) {
               Console.WriteLine(freeBytesForUser);
               Console.WriteLine(totalBytes);
               Console.WriteLine(freeBytes);
           }
       }
   }
   

2. Use the system management interface. There is another answer in this post which describes this. This method is really designed for use in scripting languages such as PowerShell. It performs a lot of fluff just to get the right object. Ultimately, I suspect, this method boils down to calling GetDiskFreeSpaceEx.

Anybody doing any serious Windows development in C# will probably end up calling many Win32 functions. The .NET framework just doesn't cover 100% of the Win32 API. Any large program will quickly uncover gaps in the .NET libraries that are only available through the Win32 API. I would get hold of one of the Win32 wrappers for .NET and include this in your project. This will give you instant access to just about every Win32 API.

Answer 2

Use WMI

using System.Management;

// Get all the network drives (drivetype=4)
SelectQuery query = new SelectQuery("select Name, VolumeName, FreeSpace from win32_logicaldisk where drivetype=4");
ManagementObjectSearcher searcher = new ManagementObjectSearcher(query);
foreach (ManagementObject drive in searcher.Get())
{
    string Name = (string)drive["Name"];
    string VolumeName = (string)drive["VolumeName"];
    UInt64 freeSpace = (UInt64)drive["FreeSpace"];
}

based on (stolen from) http://www.dreamincode.net/code/snippet1576.htm