How can I get the total physical memory in C#?

Question

I am using the GlobalMemoryStatusEx function to retrieve information about memory, but this function doesn't work correctly. It returns 0 for all properties. I don't think this function works in my Windows 7 environment.

    [StructLayout(LayoutKind.Sequential)]
    internal struct MEMORYSTATUSEX
    {
        internal uint dwLength;
        internal uint dwMemoryLoad;
        internal ulong ullTotalPhys;
        internal ulong ullAvailPhys;
        internal ulong ullTotalPageFile;
        internal ulong ullAvailPageFile;
        internal ulong ullTotalVirtual;
        internal ulong ullAvailVirtual;
        internal ulong ullAvailExtendedVirtual;
    }
    [return: MarshalAs(UnmanagedType.Bool)]
    [DllImport("Kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    internal static extern bool GlobalMemoryStatusEx(ref MEMORYSTATUSEX lpBuffer);

    private void btnGlobalMemoryStatusEX_Click(object sender, EventArgs e)
    {
        MEMORYSTATUSEX statEX = new MEMORYSTATUSEX();
        GlobalMemoryStatusEx(ref statEX);

        double d = (double)statEX.ullTotalPhys;
    }

Can anybody tell me where I went wrong with wrong code?

Answer 1

I find my mistake from: http://www.pinvoke.net/default.aspx/kernel32/GlobalMemoryStatusEx.html

I Changed

internal static extern bool GlobalMemoryStatusEx(ref MEMORYSTATUSEX lpBuffer);

To

static extern bool GlobalMemoryStatusEx([In, Out] MEMORYSTATUSEX lpBuffer);

and changed

GlobalMemoryStatusEx(ref statEX);

To

GlobalMemoryStatusEx(statEX);

It work correctly. Tanks

Answer 2

How about:

My.Computer.Info.TotalPhysicalMemory
My.Computer.Info.AvailablePhysicalMemory