c#调用api(FindFirstFile,FindNextFile)高效遍历目录文件

在c#下遍历目录，应用最多的应该就是 System.IO.DirectoryInfo.GetDirectories或GetFiles了，但是当目录特别大，文件特别多时，效率不尽人意，此时我们很容易想到三个Win32API函数 FindFirstFile，FindNextFile和FindClose。这三个API搭配使用就能遍历文件和子目录了，而且可以遍历的时候随时中止，避免无谓的操作。在网上搜了一下，发现这方面的文章转载最多的应该就是/article/4704630.html
这篇了，但是按照文中描述的方法，并不能遍历子目录，没办法，就自己想办法，重新写了一个。

以下为源代码：

#region 声明WIN32API函数以及结构 **************************************
[Serializable,
System.Runtime.InteropServices.StructLayout
(System.Runtime.InteropServices.LayoutKind.Sequential,
CharSet = System.Runtime.InteropServices.CharSet.Auto
),
System.Runtime.InteropServices.BestFitMapping(false)]
private struct WIN32_FIND_DATA
{
public int dwFileAttributes;
public int ftCreationTime_dwLowDateTime;
public int ftCreationTime_dwHighDateTime;
public int ftLastAccessTime_dwLowDateTime;
public int ftLastAccessTime_dwHighDateTime;
public int ftLastWriteTime_dwLowDateTime;
public int ftLastWriteTime_dwHighDateTime;
public int nFileSizeHigh;
public int nFileSizeLow;
public int dwReserved0;
public int dwReserved1;
[System.Runtime.InteropServices.MarshalAs
(System.Runtime.InteropServices.UnmanagedType.ByValTStr,
SizeConst = 260)]
public string cFileName;
[System.Runtime.InteropServices.MarshalAs
(System.Runtime.InteropServices.UnmanagedType.ByValTStr,
SizeConst = 14)]
public string cAlternateFileName;
}
[System.Runtime.InteropServices.DllImport
("kernel32.dll",
CharSet = System.Runtime.InteropServices.CharSet.Auto,
SetLastError = true)]
private static extern IntPtr FindFirstFile(string pFileName, ref WIN32_FIND_DATA pFindFileData);
[System.Runtime.InteropServices.DllImport
("kernel32.dll",
CharSet = System.Runtime.InteropServices.CharSet.Auto,
SetLastError = true)]
private static extern bool FindNextFile(IntPtr hndFindFile, ref WIN32_FIND_DATA lpFindFileData);
[System.Runtime.InteropServices.DllImport("kernel32.dll", SetLastError = true)]
private static extern bool FindClose(IntPtr hndFindFile);
#endregion

//具体方法函数

Stack<string> m_scopes = new Stack<string>();
private static readonly IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);
WIN32_FIND_DATA FindFileData;
private System.IntPtr hFind = INVALID_HANDLE_VALUE;
void FindFileInDir(string rootDir)
{
string path = rootDir;
start:
new FileIOPermission(FileIOPermissionAccess.PathDiscovery, Path.Combine(path, ".")).Demand();
if (path[path.Length - 1] != '\\')
{
path = path + "\\";
}
Response.Write("文件夹为："+path+"<br>");
hFind = FindFirstFile(Path.Combine(path,"*"), ref FindFileData);
if(hFind!=INVALID_HANDLE_VALUE)
{
do
{
if (FindFileData.cFileName.Equals(@".") || FindFileData.cFileName.Equals(@".."))
continue;
if ((FindFileData.dwFileAttributes & 0x10) != 0)
{
m_scopes.Push(Path.Combine(path, FindFileData.cFileName));
}
else
{
Response.Write(FindFileData.cFileName+"<br>");
}
}
while (FindNextFile(hFind, ref FindFileData));
}
FindClose(hFind);
if (m_scopes.Count > 0)
{
path = m_scopes.Pop();
goto start;
}
}

//调用方法如下：

FindFileInDir(@"D:");