如何使用WINAPI和C ++提取可执行文件的文件描述?

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问题描述

我正在尝试提取可执行文件的文件描述.右键单击文件，选择属性"，然后在常规"选项卡中，便会看到文件描述.

I am trying to extract the file description of executables. The file description is the one seen when you right click on a file, choose Properties and it is in the General tab.

我尝试使用此处找到的算法: https://docs.microsoft.com/zh-cn/windows/desktop/api/winver/nf-winver-verqueryvaluea ，但是对于某些文件，返回的文件描述为空，尽管我可以在属性窗口.例如，如果我创建一个可执行文件，则返回的文件描述将为空，但是在属性"窗口中，其文件描述与其名称相同.如何为常规"选项卡中包含一个可执行文件的每个可执行文件提取文件描述，而不会得到空字符串?

I have tried using the algorithm found here: https://docs.microsoft.com/en-us/windows/desktop/api/winver/nf-winver-verqueryvaluea but for some files the file description returned is empty although I can see it in the Properties window. For example, if I create an executable the file description returned will be empty, but in the Properties window its file description is the same as its name. How can I extract the file description for every executable that has one in the General tab and not get empty strings?

我按以下顺序使用这些功能:

I am using the functions in the following order:

GetFileVersionInfoSize

GetFileVersionInfo

VerQueryValue

StringCchPrintfW

VerQueryValue

StringCchCopyNW

有时它在VerQueryValue失败，有时在GetFileVersionInfo失败.我还注意到Microsoft.Photos.exe

Sometimes it fails at VerQueryValue and sometimes it fails at GetFileVersionInfo. I have also noticed that it fails for Microsoft.Photos.exe

推荐答案

如果要模仿shell行为，请使用shell API，特别是产权系统.

If you want to mimic the shells behaviour, use the shell API, specifically its property system.

可以使用在"Propkey.h"中定义的一组预定义常数来查询属性对话框中所示的大多数数据.在这种情况下，我们需要 System.FileDescription属性.要查询它，我们需要它的PKEY，它是 PKEY_FileDescription .

Most of the data shown in the properties dialog can be queried using a set of predefined constants, which are defined in "Propkey.h". In this case we want the System.FileDescription property. To query it, we need its PKEY, which is PKEY_FileDescription.

查询属性最简单的方法之一是 IShellItem2 :: GetString() 方法.out参数 ppsz 返回指向字符串的指针，必须使用 CoTaskMemFree()将其释放.该参考文献未提及，但这是释放外壳程序为您分配的内存的常用方法.

One of the easiest ways to query a property is the IShellItem2::GetString() method. The out parameter ppsz returns a pointer to a string, which must be freed using CoTaskMemFree(). This is not mentioned by the reference, but is the usual way to free memory allocated for you by the shell.

要从文件系统路径获取IShellItem2接口，我们可以使用 SHCreateItemFromParsingName() .

To obtain an IShellItem2 interface from a filesystem path, we can use SHCreateItemFromParsingName().

在下面的示例中，我将可重用代码包装在函数 GetShellPropStringFromPath()中.

In the following example, I've wrapped up the reusable code in the function GetShellPropStringFromPath().

示例C ++控制台应用程序:

#include <Windows.h>
#include <ShlObj.h>    // Shell API
#include <Propkey.h>   // PKEY_* constants
#include <atlbase.h>   // CComPtr, CComHeapPtr
#include <iostream>
#include <io.h>
#include <fcntl.h>
#include <string>
#include <system_error>

// Wrapper for SHCreateItemFromParsingName(), IShellItem2::GetString()
// Throws std::system_error in case of any error.
std::wstring GetShellPropStringFromPath( LPCWSTR pPath, PROPERTYKEY const& key )
{
    // Use CComPtr to automatically release the IShellItem2 interface when the function returns
    // or an exception is thrown.
    CComPtr<IShellItem2> pItem;
    HRESULT hr = SHCreateItemFromParsingName( pPath, nullptr, IID_PPV_ARGS( &pItem ) );
    if( FAILED( hr ) )
        throw std::system_error( hr, std::system_category(), "SHCreateItemFromParsingName() failed" );
    
    // Use CComHeapPtr to automatically release the string allocated by the shell when the function returns
    // or an exception is thrown (calls CoTaskMemFree).
    CComHeapPtr<WCHAR> pValue;
    hr = pItem->GetString( key, &pValue );
    if( FAILED( hr ) )
        throw std::system_error( hr, std::system_category(), "IShellItem2::GetString() failed" );

    // Copy to wstring for convenience
    return std::wstring( pValue );
}

int main()
{
    CoInitialize( nullptr );   // TODO: error handling
    _setmode( _fileno( stdout ), _O_U16TEXT );  // for proper UTF-16 console output

    try
    {
        // Show some properties of Microsoft.Photos.exe (adjust path if necessary)
        LPCWSTR path = LR"(C:\Program Files\WindowsApps\Microsoft.Windows.Photos_2018.18061.17410.0_x64__8wekyb3d8bbwe\Microsoft.Photos.exe)";
        std::wcout << L"PKEY_FileDescription:      " 
                   << GetShellPropStringFromPath( path, PKEY_FileDescription ) << std::endl;
        std::wcout << L"PKEY_Software_ProductName: " 
                   << GetShellPropStringFromPath( path, PKEY_Software_ProductName ) << std::endl;
    }
    catch( std::system_error const& e )
    {
        std::cout << "ERROR: " << e.what() << "\nError code: " << e.code() << std::endl;
    }

    CoUninitialize();
}

输出:

PKEY_FileDescription:      Microsoft.Photos.exe
PKEY_Software_ProductName: Microsoft Photos

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