IFileOpenDialog, IFileSaveDialog examples.

win32_ifile_examples.cpp

#include <iostream>
#include <windows.h>
#include <shobjidl.h>
#include <string>
#include <vector>

/**
 * @brief Open a dialog to select item(s) or folder(s).
 * @param paths Specifies the reference to the string vector that will receive the file or folder path(s). [IN]
 * @param selectFolder Specifies whether to select folder(s) rather than file(s). (optional)
 * @param multiSelect Specifies whether to allow the user to select multiple items. (optional)
 * @note If no item(s) were selected, the function still returns true, and the given vector is unmodified.
 * @note `<windows.h>`, `<string>`, `<vector>`, `<shobjidl.h>`
 * @return Returns true if all the operations are successfully performed, false otherwise.
 */
bool OpenFileDialog(std::vector<std::wstring> &paths, bool selectFolder = false, bool multiSelect = false)
{
    IFileOpenDialog *p_file_open = nullptr;
    bool are_all_operation_success = false;
    while (!are_all_operation_success)
    {
        HRESULT hr = CoCreateInstance(CLSID_FileOpenDialog, NULL, CLSCTX_ALL,
                                      IID_IFileOpenDialog, reinterpret_cast<void **>(&p_file_open));
        if (FAILED(hr))
            break;

        if (selectFolder || multiSelect)
        {
            FILEOPENDIALOGOPTIONS options = 0;
            hr = p_file_open->GetOptions(&options);
            if (FAILED(hr))
                break;

            if (selectFolder)
                options |= FOS_PICKFOLDERS;
            if (multiSelect)
                options |= FOS_ALLOWMULTISELECT;

            hr = p_file_open->SetOptions(options);
            if (FAILED(hr))
                break;
        }

        hr = p_file_open->Show(NULL);
        if (hr == HRESULT_FROM_WIN32(ERROR_CANCELLED)) // No items were selected.
        {
            are_all_operation_success = true;
            break;
        }
        else if (FAILED(hr))
            break;

        IShellItemArray *p_items;
        hr = p_file_open->GetResults(&p_items);
        if (FAILED(hr))
            break;
        DWORD total_items = 0;
        hr = p_items->GetCount(&total_items);
        if (FAILED(hr))
            break;

        for (int i = 0; i < static_cast<int>(total_items); ++i)
        {
            IShellItem *p_item;
            p_items->GetItemAt(i, &p_item);
            if (SUCCEEDED(hr))
            {
                PWSTR path;
                hr = p_item->GetDisplayName(SIGDN_FILESYSPATH, &path);
                if (SUCCEEDED(hr))
                {
                    paths.push_back(path);
                    CoTaskMemFree(path);
                }
                p_item->Release();
            }
        }

        p_items->Release();
        are_all_operation_success = true;
    }

    if (p_file_open)
        p_file_open->Release();
    return are_all_operation_success;
}

/**
 * @brief Open a dialog to save an item.
 * @param path Specifies the reference to the string that will receive the target save path. [IN]
 * @param defaultFileName Specifies the default save file name. (optional)
 * @param pFilterInfo Specifies the pointer to the pair that contains filter information. (optional)
 * @note If no path was selected, the function still returns true, and the given string is unmodified.
 * @note `<windows.h>`, `<string>`, `<vector>`, `<shobjidl.h>`
 * @return Returns true if all the operations are successfully performed, false otherwise.
 */
bool SaveFileDialog(std::wstring &path, std::wstring defaultFileName = L"", std::pair<COMDLG_FILTERSPEC *, int> *pFilterInfo = nullptr)
{
    IFileSaveDialog *p_file_save = nullptr;
    bool are_all_operation_success = false;
    while (!are_all_operation_success)
    {
        HRESULT hr = CoCreateInstance(CLSID_FileSaveDialog, NULL, CLSCTX_ALL,
                                      IID_IFileSaveDialog, reinterpret_cast<void **>(&p_file_save));
        if (FAILED(hr))
            break;

        if (!pFilterInfo)
        {
            COMDLG_FILTERSPEC save_filter[1];
            save_filter[0].pszName = L"All files";
            save_filter[0].pszSpec = L"*.*";
            hr = p_file_save->SetFileTypes(1, save_filter);
            if (FAILED(hr))
                break;
            hr = p_file_save->SetFileTypeIndex(1);
            if (FAILED(hr))
                break;
        }
        else
        {
            hr = p_file_save->SetFileTypes(pFilterInfo->second, pFilterInfo->first);
            if (FAILED(hr))
                break;
            hr = p_file_save->SetFileTypeIndex(1);
            if (FAILED(hr))
                break;
        }

        if (!defaultFileName.empty())
        {
            hr = p_file_save->SetFileName(defaultFileName.c_str());
            if (FAILED(hr))
                break;
        }

        hr = p_file_save->Show(NULL);
        if (hr == HRESULT_FROM_WIN32(ERROR_CANCELLED)) // No item was selected.
        {
            are_all_operation_success = true;
            break;
        }
        else if (FAILED(hr))
            break;

        IShellItem *p_item;
        hr = p_file_save->GetResult(&p_item);
        if (FAILED(hr))
            break;

        PWSTR item_path;
        hr = p_item->GetDisplayName(SIGDN_FILESYSPATH, &item_path);
        if (FAILED(hr))
            break;
        path = item_path;
        CoTaskMemFree(item_path);
        p_item->Release();

        are_all_operation_success = true;
    }

    if (p_file_save)
        p_file_save->Release();
    return are_all_operation_success;
}

int main()
{
    HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE);
    if (FAILED(hr))
    {
        std::cout << "Failed to initialize COM library.\n";
        return -1;
    }

    // Select an example.
    std::cout << "1. Select an item.\n";
    std::cout << "2. Select a folder.\n";
    std::cout << "3. Select multiple items.\n";
    std::cout << "4. Save an item.\n";
    std::cout << "5. Save an item with filters.\n";
    std::cout << "Select an example: ";
    int choice = 0;
    std::cin >> choice;
    switch (choice)
    {
    // Example: Select an item.
    case 1:
    {
        std::vector<std::wstring> paths;
        if (OpenFileDialog(paths))
        {
            if (!paths.empty())
            {
                std::cout << "Total items: " << paths.size() << "\n";
                for (int i = 0; i < static_cast<int>(paths.size()); ++i)
                    std::wcout << L"Path " << std::to_wstring(i + 1) << L": " << paths[i] << L"\n";
            }
            else
                std::cout << "No item were selected.\n";
        }

        break;
    }
    // Example: Select a folder.
    case 2:
    {
        std::vector<std::wstring> paths;
        if (OpenFileDialog(paths, true))
        {
            if (!paths.empty())
            {
                std::cout << "Total items: " << paths.size() << "\n";
                for (int i = 0; i < static_cast<int>(paths.size()); ++i)
                    std::wcout << L"Path " << std::to_wstring(i + 1) << L": " << paths[i] << L"\n";
            }
            else
                std::cout << "No item were selected.\n";
        }

        break;
    }
    // Example: Select multiple items.
    case 3:
    {
        std::vector<std::wstring> paths;
        if (OpenFileDialog(paths, false, true))
        {
            if (!paths.empty())
            {
                std::cout << "Total items: " << paths.size() << "\n";
                for (int i = 0; i < static_cast<int>(paths.size()); ++i)
                    std::wcout << L"Path " << std::to_wstring(i + 1) << L": " << paths[i] << L"\n";
            }
            else
                std::cout << "No item were selected.\n";
        }

        break;
    }
    // Example: Save an item.
    case 4:
    {
        std::wstring path = L"";
        if (SaveFileDialog(path, L"Some file.txt"))
        {
            if (!path.empty())
            {
                std::wcout << L"Selected save path:  " << path << L"\n";
            }
            else
                std::cout << "No item were selected.\n";
        }

        break;
    }
    // Example: Save an item with filters.
    case 5:
    {
        std::wstring path = L"";
        const unsigned int total_filters = 3;
        COMDLG_FILTERSPEC filters[total_filters];
        filters[0].pszName = L"All files. (*.*)";
        filters[0].pszSpec = L"*.*";
        filters[1].pszName = L"Image files. (.bmp, .jpg, .png)";
        filters[1].pszSpec = L"*.bmp;*.jpg;*.png";
        filters[2].pszName = L"Specific file. (unique_file.txt)";
        filters[2].pszSpec = L"unique_file.txt";
        std::pair<COMDLG_FILTERSPEC *, int> filter_info = std::make_pair<COMDLG_FILTERSPEC *, int>(filters, total_filters);
        if (SaveFileDialog(path, L"", &filter_info))
        {
            if (!path.empty())
            {
                std::wcout << L"Selected save path: " << path << L"\n";
            }
            else
                std::cout << "No item were selected.\n";
        }

        break;
    }
    }

    CoUninitialize();

    return 0;
}