C# Signature:

[DllImport("kernel32.dll")]
static extern bool GlobalMemoryStatusEx(ref MEMORYSTATUSEX lpBuffer);

User-Defined Types:

MEMORYSTATUSEX

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

private void DisplayMemory()

        {
            string[] Drives = System.IO.Directory.GetLogicalDrives();
            long tm = System.GC.GetTotalMemory(true);
            UInt64 UserAvailable=0,Capacity=0,Available=0;
            if(Drives!=null)
            {
                int retval = GetDiskFreeSpaceExA(Drives[0],ref UserAvailable,ref Capacity,ref Available);
                this.lblDiskFree.Text = Available.ToString();
                this.lblDiskTotal.Text = Capacity.ToString();
            }
            MEMORYSTATUSEX msex=new MEMORYSTATUSEX();
            msex.dwLength = (uint)Marshal.SizeOf(msex);
            int retval2 = GlobalMemoryStatusEx(ref msex);
            this.lblMemoryFree.Text = msex.ullAvailPhys.ToString();
            this.lblMemoryTotal.Text = msex.ullTotalPhys.ToString();
        }

        private struct MEMORYSTATUSEX
                {
                    public uint dwLength;  
                    public uint dwMemoryLoad;  
                    public UInt64 ullTotalPhys;  
                    public UInt64 ullAvailPhys;  
                    public UInt64 ullTotalPageFile;  
                    public UInt64 ullAvailPageFile;  
                    public UInt64 ullTotalVirtual;  
                    public UInt64 ullAvailVirtual;  
                    public UInt64 ullAvailExtendedVirtual;
                };

        [DllImport("kernel32.dll")]
        private static extern int GetDiskFreeSpaceExA(  string lpDirectoryName,
            ref System.UInt64 lpFreeBytesAvailable,
            ref System.UInt64 lpTotalNumberOfBytes,
            ref System.UInt64 lpTotalNumberOfFreeBytes
            );

        [DllImport("kernel32.dll")]
        private static extern int GlobalMemoryStatusEx(
            ref MEMORYSTATUSEX msex
            );

Alternative Managed API:

Do you know one? Please contribute it!