调用 SHFileOperation 删除文件夹时返回 1026 （0x402）错误的原因

如题，昨天遇到一个产品中的清空功能不可用的问题。现象也比较奇怪：当点击界面上的清空历史列表功能的时候，要删除的目标文件夹有时能被删除，有时却不能被删除。经过调试，确认问题出在 SHFileOperation 的调用上，它有时会返回错误码：1026 （0x402 ）。先看下这个API的原型：

int SHFileOperation(

LPSHFILEOPSTRUCT lpFileOp

);

其中结构体 LPSHFILEOPSTRUCT 的定义为：

 

	typedef struct _SHFILEOPSTRUCT {
		HWND hwnd;
		 UINT wFunc;
		LPCTSTR pFrom;
		 LPCTSTR pTo;
		 FILEOP_FLAGS fFlags;
		 BOOL fAnyOperationsAborted;
		LPVOID hNameMappings;
		LPCTSTR lpszProgressTitle;
	} SHFILEOPSTRUCT, *LPSHFILEOPSTRUCT;

 经过一番谷歌，终于查到原因：调这个 API 时传入的结构体的成员 pFrom 必须以两个 '/0' 字符结尾，而不论有没有指定 fFlags 为 
FOF_MULTIDESTFILES！


嗐，原来是这个原因！


原来是 MSDN 没看清楚，写代码时没有多加一个 '/0'。下面是 MSDN 的部分说明：


  
  
   
   pFrom

   
   


  
  

  
  

   
   Address of a buffer to specify one or more source file names. These names 
   
   

must be fully qualified paths. Standard Microsoft MS-DOS wild cards, such as 
   
   

"*", are permitted in the file-name position. Although this member is declared 
   
   

as a null-terminated string, it is used as a buffer to hold multiple file names. 
   
   

Each file name must be terminated by a single NULL character.
   
    An additional NULL 

character must be appended to the end of the final name to indicate the end of 



   
   pFrom


.
  
  

下面是一个更正后的 Demo:

#include "stdafx.h"
#include <Windows.h>
#include <string>
#include <iostream>

HRESULT RemoveDir( std::wstring& wstrTargetPath )
{
	if (wstrTargetPath.empty() || wstrTargetPath.length() > MAX_PATH)
	{
		return E_INVALIDARG;
	}

	/*
	* 元素全部初始化为 '/0'，保证结尾至少有两个 '/0'
	*/
	WCHAR	pwszTargetPath[MAX_PATH + 1]	= {0};

	::wcsncpy_s(
		pwszTargetPath,
		_countof(pwszTargetPath),
		wstrTargetPath.c_str(),
		wstrTargetPath.length()
		);

	SHFILEOPSTRUCTW FileOp =    
	{   
		NULL,
		FO_DELETE,
		pwszTargetPath,
		NULL,
		FOF_SILENT | FOF_NOERRORUI | FOF_NOCONFIRMATION,
		FALSE,
		NULL,
		NULL
	};   

	int nRet = ::SHFileOperationW(&FileOp);

	return HRESULT_FROM_WIN32(nRet);
}

int _tmain(int argc, _TCHAR* argv[])
{
	std::wcout.imbue(std::locale("chs"));

	std::wstring	wstrPathToRemove(L"C://Documents and Settings//All Users//Application Data//TestDir");

	HRESULT	hRet = RemoveDir( wstrPathToRemove );
	if (SUCCEEDED(hRet))
	{
		std::wcout << L"Remove directory/"" << wstrPathToRemove
			<< L"/" succeeded." << std::endl;
	}
	else
	{
		std::wcout << L"Remove directory/"" << wstrPathToRemove
			<< L"/" failed with error: 0x" << std::hex << hRet << L"." << std::endl;
	}
	return 0;
}