wxwidgets直接获取系统图标，效果类似QFileIconProvider

目前只做了windows版本，用法类似QFileIconProvider

// 头文件
#ifndef WXFILEICONPROVIDER_H
#define WXFILEICONPROVIDER_H

#include <wx/wx.h>
#include <wx/icon.h>
#include <wx/image.h>
#include <wx/bmpcbox.h>  // Include for wxBitmapBundle

class wxFileIconProvider : public wxObject
{
public:
    wxFileIconProvider();
    virtual ~wxFileIconProvider();

    // Get icon for the given path
    virtual wxBitmapBundle GetIcon(const wxString& path);
};

#endif

#include "wxFileIconProvider.h"
#include <wx/filename.h>

#ifdef __WXMSW__
#include <windows.h>
#include <shellapi.h>
#include <shlobj.h>
#include <wx/msw/private.h>
#include <wx/bitmap.h>
#include <wx/image.h>
#include <wx/bmpcbox.h>

wxBitmapBundle wxFileIconProvider::GetIcon(const wxString &path)
{
    wxBitmapBundle bundle;
    SHFILEINFO shFileInfo;
    wxFileName fileName(path);

    if (!fileName.Exists())
    {
        wxLogMessage("Error: File does not exist or is not accessible: %s", path);
        return bundle;
    }

    wxString absolutePath = fileName.GetFullPath();
    DWORD_PTR result = SHGetFileInfo(absolutePath.wc_str(), 0, &shFileInfo, sizeof(shFileInfo), SHGFI_ICON | SHGFI_SMALLICON | SHGFI_LARGEICON);

    if (result)
    {
        if (shFileInfo.hIcon)
        {
            wxIcon smallIcon;
            smallIcon.CreateFromHICON(shFileInfo.hIcon);

            // Extract Large Icon
            SHFILEINFO largeFileInfo = shFileInfo;
            largeFileInfo.iIcon = 0;
            SHGetFileInfo(absolutePath.wc_str(), 0, &largeFileInfo, sizeof(largeFileInfo), SHGFI_ICON | SHGFI_LARGEICON);
            wxIcon largeIcon;
            largeIcon.CreateFromHICON(largeFileInfo.hIcon);

            if (smallIcon.IsOk() && largeIcon.IsOk())
            {
                wxBitmap smallBitmap = wxBitmap(smallIcon);
                wxBitmap largeBitmap = wxBitmap(largeIcon);

                bundle = wxBitmapBundle::FromBitmaps(smallBitmap, largeBitmap);
                DestroyIcon(shFileInfo.hIcon);
                DestroyIcon(largeFileInfo.hIcon);
            }
            else
            {
                DestroyIcon(shFileInfo.hIcon);
                DestroyIcon(largeFileInfo.hIcon);
            }
        }
        else
        {
            DestroyIcon(shFileInfo.hIcon);
        }
    }
    else
    {
        DWORD error = GetLastError();
        wxLogMessage("SHGetFileInfo failed with error code: %lu", error);
    }
    return bundle;
}

#endif

wxFileIconProvider::wxFileIconProvider() {}
wxFileIconProvider::~wxFileIconProvider() {}

// 用法
wxSize iconSize = wxSize(42, 42);
wxFileIconProvider iconProvider;
wxString filePath = "c:/users/xxx/"; // 传入文件夹或文件的路径
wxBitmapBundle bundle = iconProvider.GetIcon(filePath);
wxBitmapButton *btTest = new wxBitmapButton(this, wxID_ANY, bundle.GetBitmap(iconSize),
                                                wxDefaultPosition, buttonSize);

传入路径，出现的就是为文件夹图标，传入文件，则是文件类型相对应的图标。