在Windows CE上为GlobalMemoryStatusEx提供PInvoke

Question

如果您不了解或了解Windows CE和Compact Framework，请不要对此进行投票。感谢。

有人知道这个函数在WinCE上是否可用，以及（如果有的话）DLL是什么？我试过从“coredll.dll”和“kernel.dll”PInvoke这个。 Win32版本来自“kernel32.dll”。

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("kernel.dll")] // and "coredll.dll" also doesn't work
public static extern bool GlobalMemoryStatusEx([In,Out] MEMORYSTATUSEX lpBuffer);

当我尝试使用异常“无法找到PInvoke DLL'kernel.dll'时，上述函数失败。”

PS：我使用了大量的PInvoked函数，例如：

[DllImport("coredll.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, int nMsg, IntPtr wParam, IntPtr lParam);

Answer 1

只有GlobalMemoryStatus电话，而不是扩展（... Ex）版本。它位于coredll.dll中，请参阅http://pinvoke.net/default.aspx/coredll.GlobalMemoryStatus

Answer 2

已经实现了C.Evenhuis建议的答案，并且效果很好。这是以后可能需要此功能的任何人的代码：

// Structure to allow getting memory usage
public struct MEMORYSTATUS
{
        public int nLength;
        public int nMemoryLoad;
        public uint uTotalPhys;
        public uint uAvailPhys;
        public uint uTotalPageFile;
        public uint uAvailPageFile;
        public uint uTotalVirtual;
        public uint uAvailVirtual;
}

[DllImport("coredll", EntryPoint="GlobalMemoryStatus", SetLastError = false)]
public static extern void GlobalMemoryStatus(out MEMORYSTATUS memCE);

MEMORYSTATUS mem = new MEMORYSTATUS();
mem.nLength = Marshal.SizeOf(typeof(MEMORYSTATUS));
GlobalMemoryStatus(out mem);
// Label1.Text = (mem.uAvailPhys.ToString() + "Bytes");

Answer 3

我以这种方式使用。

/// <summary>
/// https://msdn.microsoft.com/en-us/library/ee488368.aspx
/// This structure contains information about current memory availability. The GlobalMemoryStatus function uses this structure.
/// </summary>
[StructLayout(LayoutKind.Sequential)]
public struct MemoryStatus
{
    /// <summary>
    /// Specifies the size, in bytes, of the MEMORYSTATUS structure.
    /// Set this member to sizeof(MEMORYSTATUS) when passing it to the GlobalMemoryStatus function.
    /// </summary>
    public int Length;
    /// <summary>
    /// Specifies a number between zero and 100 that gives a general idea of current memory use, in which zero indicates no memory use and 100 indicates full memory use.
    /// </summary>
    public uint MemoryLoad;
    /// <summary>
    /// Indicates the total number of bytes of physical memory.
    /// </summary>
    public uint TotalPhys;
    /// <summary>
    /// Indicates the number of bytes of physical memory available.
    /// </summary>
    public uint AvailPhys;
    /// <summary>
    /// Indicates the total number of bytes that can be stored in the paging file.
    /// This number does not represent the physical size of the paging file on disk.
    /// </summary>
    public uint TotalPageFile;
    /// <summary>
    /// Indicates the number of bytes available in the paging file.
    /// </summary>
    public uint AvailPageFile;
    /// <summary>
    /// Indicates the total number of bytes that can be described in the user mode portion of the virtual address space of the calling process.
    /// </summary>
    public uint TotalVirtual;
    /// <summary>
    /// Indicates the number of bytes of unreserved and uncommitted memory in the user mode portion of the virtual address space of the calling process.
    /// </summary>
    public uint AvailVirtual;
    [DllImport("coredll.dll")]
    private static extern void GlobalMemoryStatus(ref MemoryStatus ms);
    public static string GetMemoryStatus()
    {
        var retValue = new StringBuilder();
        MemoryStatus ms = GlobalMemoryStatus();
        retValue.AppendLine(string.Format("Memory Load {0} %", ms.MemoryLoad));
        retValue.AppendLine(string.Format("Total Phys {0} Kb", ms.TotalPhys / 1024));
        retValue.AppendLine(string.Format("Avail Phys {0} Kb", ms.AvailPhys / 1024));
        retValue.AppendLine(string.Format("Tota PFile {0} bytes", ms.TotalPageFile));
        retValue.AppendLine(string.Format("Avai PFile {0} bytes", ms.AvailPageFile));
        retValue.AppendLine(string.Format("Total Virt {0} Kb", ms.TotalVirtual / 1024));
        retValue.AppendLine(string.Format("Avail Virt {0} Kb", ms.AvailVirtual / 1024));
        return retValue.ToString();
    }

    public static MemoryStatus GlobalMemoryStatus()
    {
        MemoryStatus ms = new MemoryStatus();
        ms.Length = Marshal.SizeOf(ms);
        GlobalMemoryStatus(ref ms);
        return ms;
    }
    public static uint GetMemoryLoad()
    {
        var ms = GlobalMemoryStatus();
        return ms.MemoryLoad;
    }
}

您可以检入Windows CE SDK的WinBase.h

typedef struct _MEMORYSTATUS {
    DWORD dwLength;
    DWORD dwMemoryLoad;
    DWORD dwTotalPhys;
    DWORD dwAvailPhys;
    DWORD dwTotalPageFile;
    DWORD dwAvailPageFile;
    DWORD dwTotalVirtual;
    DWORD dwAvailVirtual;
} MEMORYSTATUS, *LPMEMORYSTATUS;

VOID
WINAPI
GlobalMemoryStatus(
    __inout LPMEMORYSTATUS lpBuffer
    );

因为SDK中的 _inout 。我用过＆＃34; 参考＆＃34;参数修饰符。

这就是全部。