Question

我正在使用codeproject中的一个项目，它基本上监视计算机上的打印活动。但是，对于64位配置，它无法正常工作。代码的下面部分是问题。无论何时打印完成，都会调用此代码。

PRINTER_NOTIFY_INFO info = (PRINTER_NOTIFY_INFO)Marshal.PtrToStructure(pNotifyInfo, typeof(PRINTER_NOTIFY_INFO));                        
int pData = (int)pNotifyInfo + Marshal.SizeOf(typeof(PRINTER_NOTIFY_INFO));
PRINTER_NOTIFY_INFO_DATA[] data = new PRINTER_NOTIFY_INFO_DATA[info.Count];
for (uint i = 0; i < info.Count; i++)
{
    data[i] = (PRINTER_NOTIFY_INFO_DATA)Marshal.PtrToStructure((IntPtr)pData, typeof(PRINTER_NOTIFY_INFO_DATA));
    pData += Marshal.SizeOf(typeof(PRINTER_NOTIFY_INFO_DATA));
}

调试显示数据[i] .field值始终为0.但在32位中它可以正常工作。我认为没有正确定义PRINTER_NOTIFY_INFO_DATA。目前我正在使用以下代码。任何人都可以解决这个问题，以便在64位上正常工作吗？

[StructLayout(LayoutKind.Sequential)]
public struct PRINTER_NOTIFY_INFO
{
    public uint Version;
    public uint Flags;
    public uint Count;
}


[StructLayout(LayoutKind.Sequential)]
public struct PRINTER_NOTIFY_INFO_DATA_DATA
{
    public uint cbBuf;
    public IntPtr pBuf;
}

[StructLayout(LayoutKind.Explicit)]
public struct PRINTER_NOTIFY_INFO_DATA_UNION
{
    [FieldOffset(0)]
    private uint adwData0;
    [FieldOffset(4)]
    private uint adwData1;
    [FieldOffset(0)]
    public PRINTER_NOTIFY_INFO_DATA_DATA Data;
    public uint[] adwData
    {
        get
        {
            return new uint[] { this.adwData0, this.adwData1 };
        }
    }
}

// Structure borrowed from http://lifeandtimesofadeveloper.blogspot.com/2007/10/unmanaged-structures-padding-and-c-part_18.html.
[StructLayout(LayoutKind.Sequential)]
public struct PRINTER_NOTIFY_INFO_DATA
{
    public ushort Type;
    public ushort Field;
    public uint Reserved;
    public uint Id;
    public PRINTER_NOTIFY_INFO_DATA_UNION NotifyData;
}

我正在使用MS XPS驱动程序测试打印。代码项目文章是Here

Answer 1

由于Data Alignment，它无法正常用于64位配置。

所以我建议您按如下方式更改PRINTER_NOTIFY_INFO：

[StructLayout(LayoutKind.Sequential)]
public struct PRINTER_NOTIFY_INFO
{
    public uint Version;
    public uint Flags;
    public uint Count;
    public PRINTER_NOTIFY_INFO_DATA_UNION aData;
}

然后使用Marshal.OffsetOf代替Marshal.SizeOf：

PRINTER_NOTIFY_INFO info = (PRINTER_NOTIFY_INFO)Marshal.PtrToStructure(pNotifyInfo, typeof(PRINTER_NOTIFY_INFO));                        
long pData = (long)pNotifyInfo + (long)Marshal.OffsetOf(typeof(PRINTER_NOTIFY_INFO), "aData");
PRINTER_NOTIFY_INFO_DATA[] data = new PRINTER_NOTIFY_INFO_DATA[info.Count];
for (uint i = 0; i < info.Count; i++)
{
    data[i] = (PRINTER_NOTIFY_INFO_DATA)Marshal.PtrToStructure((IntPtr)pData, typeof(PRINTER_NOTIFY_INFO_DATA));
    pData += (long)Marshal.SizeOf(typeof(PRINTER_NOTIFY_INFO_DATA));
}

Answer 2

另一种解决方案是在写入后添加4个字节：PRINTER_NOTIFY_INFO填充以进行数据对齐（32int仅是64位的一半）+ 4个字节使之成为64位。

还要注意：PRINTER_NOTIFY_INFO_DATA_DATA => IntPtr pBuf;是inptr，因此在Windows 64位中为64位。这使得整个类的数据价值为128位。（所以也不要忘记在此处添加额外的4个字节。

保留或Id似乎也有4个额外的字节，因此我最终在最后每个info_data添加8个额外的字节，以使其正常工作。

如何正确定义PRINT_NOTIFY_INFO_DATA？

2 个答案: