我已经简化/更新了Jeff Brown 在 CodeProject 上的 CreateJunction 代码，例如使用自动编组将结构传递给 DeviceIoControl 而不必手动管理内存。我这样做只是为了创建一个联结，因为您可以使用 Directory.Delete() 进行删除，.Net 的 GetAttributes 返回它是否具有重解析点。
我还删除了目标目录存在检查，因为我发现能够创建与不存在或稍后将存在的文件夹的连接很有用。（不同的驱动器等）
我无法弄清楚的一件事是添加到结构成员和 nInBufferSize DeviceIoControl 参数的字符串长度的大小，它们似乎不等于 Marshal.SizeOf 返回值。
我是在 VB.Net 中完成的，所以我使用 IC#Code 的 CodeConverter 扩展将其转换为 C#：
using System;
using System.ComponentModel;
using System.IO;
using System.Runtime.InteropServices;
using Microsoft.Win32.SafeHandles;
public class Junction
{
[Flags]
private enum Win32FileAccess : uint
{
GenericRead = 0x80000000U,
GenericWrite = 0x40000000U,
GenericExecute = 0x20000000U,
GenericAll = 0x10000000U
}
[Flags]
private enum Win32FileAttribute : uint
{
AttributeReadOnly = 0x1U,
AttributeHidden = 0x2U,
AttributeSystem = 0x4U,
AttributeDirectory = 0x10U,
AttributeArchive = 0x20U,
AttributeDevice = 0x40U,
AttributeNormal = 0x80U,
AttributeTemporary = 0x100U,
AttributeSparseFile = 0x200U,
AttributeReparsePoint = 0x400U,
AttributeCompressed = 0x800U,
AttributeOffline = 0x1000U,
AttributeNotContentIndexed = 0x2000U,
AttributeEncrypted = 0x4000U,
AttributeIntegrityStream = 0x8000U,
AttributeVirtual = 0x10000U,
AttributeNoScrubData = 0x20000U,
AttributeEA = 0x40000U,
AttributeRecallOnOpen = 0x40000U,
AttributePinned = 0x80000U,
AttributeUnpinned = 0x100000U,
AttributeRecallOnDataAccess = 0x400000U,
FlagOpenNoRecall = 0x100000U,
/// <summary>
/// Normal reparse point processing will not occur; CreateFile will attempt to open the reparse point. When a file is opened, a file handle is returned,
/// whether or not the filter that controls the reparse point is operational.
/// <br />This flag cannot be used with the <see cref="FileMode.Create"/> flag.
/// <br />If the file is not a reparse point, then this flag is ignored.
/// </summary>
FlagOpenReparsePoint = 0x200000U,
FlagSessionAware = 0x800000U,
FlagPosixSemantics = 0x1000000U,
/// <summary>
/// You must set this flag to obtain a handle to a directory. A directory handle can be passed to some functions instead of a file handle.
/// </summary>
FlagBackupSemantics = 0x2000000U,
FlagDeleteOnClose = 0x4000000U,
FlagSequentialScan = 0x8000000U,
FlagRandomAccess = 0x10000000U,
FlagNoBuffering = 0x20000000U,
FlagOverlapped = 0x40000000U,
FlagWriteThrough = 0x80000000U
}
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern SafeFileHandle CreateFile(string lpFileName, Win32FileAccess dwDesiredAccess,
FileShare dwShareMode, IntPtr lpSecurityAttributes, FileMode dwCreationDisposition,
Win32FileAttribute dwFlagsAndAttributes, IntPtr hTemplateFile);
// Because the tag we're using is IO_REPARSE_TAG_MOUNT_POINT, we use the MountPointReparseBuffer struct in the DUMMYUNIONNAME union.
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
private struct ReparseDataBuffer
{
/// <summary>Reparse point tag. Must be a Microsoft reparse point tag.</summary>
public uint ReparseTag;
/// <summary>Size, in bytes, of the reparse data in the buffer that <see cref="PathBuffer"/> points to.</summary>
public ushort ReparseDataLength;
/// <summary>Reserved; do not use.</summary>
private ushort Reserved;
/// <summary>Offset, in bytes, of the substitute name string in the <see cref="PathBuffer"/> array.</summary>
public ushort SubstituteNameOffset;
/// <summary>Length, in bytes, of the substitute name string. If this string is null-terminated, <see cref="SubstituteNameLength"/> does not include space for the null character.</summary>
public ushort SubstituteNameLength;
/// <summary>Offset, in bytes, of the print name string in the <see cref="PathBuffer"/> array.</summary>
public ushort PrintNameOffset;
/// <summary>Length, in bytes, of the print name string. If this string is null-terminated, <see cref="PrintNameLength"/> does not include space for the null character.</summary>
public ushort PrintNameLength;
/// <summary>
/// A buffer containing the unicode-encoded path string. The path string contains the substitute name
/// string and print name string. The substitute name and print name strings can appear in any order.
/// </summary>
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8184)]
internal string PathBuffer;
// with <MarshalAs(UnmanagedType.ByValArray, SizeConst:=16368)> Public PathBuffer As Byte()
// 16368 is the amount of bytes. since a unicode string uses 2 bytes per character, constrain to 16368/2 = 8184 characters.
}
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern bool DeviceIoControl(SafeFileHandle hDevice, uint dwIoControlCode,
[In] ReparseDataBuffer lpInBuffer, uint nInBufferSize,
IntPtr lpOutBuffer, uint nOutBufferSize,
[Out] uint lpBytesReturned, IntPtr lpOverlapped);
public static void Create(string junctionPath, string targetDir, bool overwrite = false)
{
const uint IO_REPARSE_TAG_MOUNT_POINT = 0xA0000003U;
const uint FSCTL_SET_REPARSE_POINT = 0x900A4U;
// This prefix indicates to NTFS that the path is to be treated as a non-interpreted path in the virtual file system.
const string NonInterpretedPathPrefix = @"\??\";
if (Directory.Exists(junctionPath))
{
if (!overwrite)
throw new IOException("Directory already exists and overwrite parameter is false.");
}
else
{
Directory.CreateDirectory(junctionPath);
}
targetDir = NonInterpretedPathPrefix + Path.GetFullPath(targetDir);
using (var reparsePointHandle = CreateFile(junctionPath, Win32FileAccess.GenericWrite,
FileShare.Read | FileShare.Write | FileShare.Delete, IntPtr.Zero, FileMode.Open,
Win32FileAttribute.FlagBackupSemantics | Win32FileAttribute.FlagOpenReparsePoint, IntPtr.Zero))
{
if (reparsePointHandle.IsInvalid || Marshal.GetLastWin32Error() != 0)
{
throw new IOException("Unable to open reparse point.", new Win32Exception());
}
// unicode string is 2 bytes per character, so *2 to get byte length
ushort byteLength = (ushort)(targetDir.Length * 2);
var reparseDataBuffer = new ReparseDataBuffer()
{
ReparseTag = IO_REPARSE_TAG_MOUNT_POINT,
ReparseDataLength = (ushort)(byteLength + 12u),
SubstituteNameOffset = 0,
SubstituteNameLength = byteLength,
PrintNameOffset = (ushort)(byteLength + 2u),
PrintNameLength = 0,
PathBuffer = targetDir
};
bool result = DeviceIoControl(reparsePointHandle, FSCTL_SET_REPARSE_POINT, reparseDataBuffer, (uint)(byteLength + 20), IntPtr.Zero, 0u, 0u, IntPtr.Zero);
if (!result)
throw new IOException("Unable to create junction point.", new Win32Exception());
}
}
}
和源VB.Net：
Imports System
Imports System.ComponentModel
Imports System.IO
Imports System.Runtime.InteropServices
Imports Microsoft.Win32.SafeHandles
Public Class Junction
<Flags>
Private Enum Win32FileAccess As UInteger
GenericRead = &H80000000UI
GenericWrite = &H40000000
GenericExecute = &H20000000
GenericAll = &H10000000
End Enum
<Flags>
Private Enum Win32FileAttribute As UInteger
AttributeReadOnly = &H1
AttributeHidden = &H2
AttributeSystem = &H4
AttributeDirectory = &H10
AttributeArchive = &H20
AttributeDevice = &H40
AttributeNormal = &H80
AttributeTemporary = &H100
AttributeSparseFile = &H200
AttributeReparsePoint = &H400
AttributeCompressed = &H800
AttributeOffline = &H1000
AttributeNotContentIndexed = &H2000
AttributeEncrypted = &H4000
AttributeIntegrityStream = &H8000
AttributeVirtual = &H10000
AttributeNoScrubData = &H20000
AttributeEA = &H40000
AttributeRecallOnOpen = &H40000
AttributePinned = &H80000
AttributeUnpinned = &H100000
AttributeRecallOnDataAccess = &H400000
FlagOpenNoRecall = &H100000
''' <summary>
''' Normal reparse point processing will not occur; CreateFile will attempt to open the reparse point. When a file is opened, a file handle is returned,
''' whether or not the filter that controls the reparse point is operational.
''' <br />This flag cannot be used with the <see cref="FileMode.Create"/> flag.
''' <br />If the file is not a reparse point, then this flag is ignored.
''' </summary>
FlagOpenReparsePoint = &H200000
FlagSessionAware = &H800000
FlagPosixSemantics = &H1000000
''' <summary>
''' You must set this flag to obtain a handle to a directory. A directory handle can be passed to some functions instead of a file handle.
''' </summary>
FlagBackupSemantics = &H2000000
FlagDeleteOnClose = &H4000000
FlagSequentialScan = &H8000000
FlagRandomAccess = &H10000000
FlagNoBuffering = &H20000000
FlagOverlapped = &H40000000
FlagWriteThrough = &H80000000UI
End Enum
<DllImport("kernel32.dll", SetLastError:=True, CharSet:=CharSet.Auto)>
Private Shared Function CreateFile(lpFileName As String, dwDesiredAccess As Win32FileAccess,
dwShareMode As FileShare, lpSecurityAttributes As IntPtr,
dwCreationDisposition As FileMode, dwFlagsAndAttributes As Win32FileAttribute,
hTemplateFile As IntPtr) As SafeFileHandle
End Function
' Because the tag we're using is IO_REPARSE_TAG_MOUNT_POINT, we use the MountPointReparseBuffer struct in the DUMMYUNIONNAME union.
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
Private Structure ReparseDataBuffer
''' <summary>Reparse point tag. Must be a Microsoft reparse point tag.</summary>
Public ReparseTag As UInteger
''' <summary>Size, in bytes, of the reparse data in the buffer that <see cref="PathBuffer"/> points to.</summary>
Public ReparseDataLength As UShort
''' <summary>Reserved; do not use.</summary>
Private Reserved As UShort
''' <summary>Offset, in bytes, of the substitute name string in the <see cref="PathBuffer"/> array.</summary>
Public SubstituteNameOffset As UShort
''' <summary>Length, in bytes, of the substitute name string. If this string is null-terminated, <see cref="SubstituteNameLength"/> does not include space for the null character.</summary>
Public SubstituteNameLength As UShort
''' <summary>Offset, in bytes, of the print name string in the <see cref="PathBuffer"/> array.</summary>
Public PrintNameOffset As UShort
''' <summary>Length, in bytes, of the print name string. If this string is null-terminated, <see cref="PrintNameLength"/> does not include space for the null character.</summary>
Public PrintNameLength As UShort
''' <summary>
''' A buffer containing the unicode-encoded path string. The path string contains the substitute name
''' string and print name string. The substitute name and print name strings can appear in any order.
''' </summary>
<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=8184)>
Friend PathBuffer As String
' with <MarshalAs(UnmanagedType.ByValArray, SizeConst:=16368)> Public PathBuffer As Byte()
' 16368 is the amount of bytes. since a unicode string uses 2 bytes per character, constrain to 16368/2 = 8184 characters.
End Structure
<DllImport("kernel32.dll", SetLastError:=True, CharSet:=CharSet.Auto)>
Private Shared Function DeviceIoControl(hDevice As SafeFileHandle, dwIoControlCode As UInteger,
<[In]> ByRef lpInBuffer As ReparseDataBuffer, nInBufferSize As UInteger,
lpOutBuffer As IntPtr, nOutBufferSize As UInteger,
<Out> ByRef lpBytesReturned As UInteger, lpOverlapped As IntPtr) As Boolean
End Function
Public Shared Sub Create(junctionPath As String, targetDir As String, Optional overwrite As Boolean = False)
Const IO_REPARSE_TAG_MOUNT_POINT As UInteger = &HA0000003UI
Const FSCTL_SET_REPARSE_POINT As UInteger = &H900A4
'This prefix indicates to NTFS that the path is to be treated as a non-interpreted path in the virtual file system.
Const NonInterpretedPathPrefix As String = "\??\"
If Directory.Exists(junctionPath) Then
If Not overwrite Then Throw New IOException("Directory already exists and overwrite parameter is false.")
Else
Directory.CreateDirectory(junctionPath)
End If
targetDir = NonInterpretedPathPrefix & Path.GetFullPath(targetDir)
Using reparsePointHandle As SafeFileHandle = CreateFile(junctionPath, Win32FileAccess.GenericWrite,
FileShare.Read Or FileShare.Write Or FileShare.Delete, IntPtr.Zero, FileMode.Open,
Win32FileAttribute.FlagBackupSemantics Or Win32FileAttribute.FlagOpenReparsePoint, IntPtr.Zero)
If reparsePointHandle.IsInvalid OrElse Marshal.GetLastWin32Error() <> 0 Then
Throw New IOException("Unable to open reparse point.", New Win32Exception())
End If
' unicode string is 2 bytes per character, so *2 to get byte length
Dim byteLength As UShort = CType(targetDir.Length * 2, UShort)
Dim reparseDataBuffer As New ReparseDataBuffer With {
.ReparseTag = IO_REPARSE_TAG_MOUNT_POINT,
.ReparseDataLength = byteLength + 12US,
.SubstituteNameOffset = 0,
.SubstituteNameLength = byteLength,
.PrintNameOffset = byteLength + 2US,
.PrintNameLength = 0,
.PathBuffer = targetDir
}
Dim result As Boolean = DeviceIoControl(reparsePointHandle, FSCTL_SET_REPARSE_POINT, reparseDataBuffer, byteLength + 20US, IntPtr.Zero, 0, 0, IntPtr.Zero)
If Not result Then Throw New IOException("Unable to create junction point.", New Win32Exception())
End Using
End Sub
End Class