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让Qt 具有多选文件夹和记忆上一次打开位置的文件对话框

article 2025/1/8 17:59:05

最近要做一个可以多选文件夹的功能，在网上查阅了多个资料，发现github有一段代码可以实现该功能，于是将其收入进行改造。另外qt自带的 getExistingDirectory 和 getOpenFileNames 不具有记忆上一次打开的文件夹位置。要实现多选文件夹和记忆上一次打开位置能用到的就只有IFileOpenDialog 接口了。
原代码如下
出处：https://gist.github.com/0xF5T9/3f3203950f480d348aa6d99850a26016

#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;
}
	std::vector<std::pair<std::wstring, std::wstring>> filters = {
		{L"文件类型(*.txt)", L"*.txt"},        // 过滤 .txt 文件
		
	};		
	if (auto files = GetOpenFileNames(L"导入转换的TXT文件", true, filters);files.has_value())
	{
		for (const auto& filename : files.value())
		{
		    ...
		}
	}

于是将其中的OpenFileDialog函数拿来进行改造：分别是选择文件 GetOpenFileNames 和文件夹 GetExistingDirectorys

使用时需要加入以下几个头文件：

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

GetOpenFileNames 函数定义如下：

std::optional<std::vector <std::wstring>> GetOpenFileNames(const std::wstring& dialogTitle, bool multiSelect, const std::vector<std::pair<std::wstring, std::wstring>>& filters)
{
	IFileOpenDialog* p_file_open = nullptr;
	bool are_all_operation_success = false;
	std::optional<std::vector <std::wstring>>files;
	while (!are_all_operation_success)
	{
		// Create the file dialog instance
		HRESULT hr = CoCreateInstance(CLSID_FileOpenDialog, NULL, CLSCTX_ALL,
			IID_IFileOpenDialog, reinterpret_cast<void**>(&p_file_open));
		if (FAILED(hr))
			break;

		// Set dialog title if specified
		if (!dialogTitle.empty())
		{
			hr = p_file_open->SetTitle(dialogTitle.c_str());
			if (FAILED(hr))
				break;
		}

		// Handle folder selection and multi-select options
		if ( multiSelect)
		{
			FILEOPENDIALOGOPTIONS options = 0;
			hr = p_file_open->GetOptions(&options);
			if (FAILED(hr))
				break;					
			options |= FOS_ALLOWMULTISELECT;
			hr = p_file_open->SetOptions(options);
			if (FAILED(hr))
				break;
		}
		if (!filters.empty())
		{
			std::vector<COMDLG_FILTERSPEC> filterSpecs;

			for (const auto& filter : filters)
			{
				COMDLG_FILTERSPEC spec;
				spec.pszName = filter.first.c_str();  // Filter name as LPCWSTR
				spec.pszSpec = filter.second.c_str(); // File spec (e.g. "*.txt") as LPCWSTR
				filterSpecs.push_back(spec);
			}

			// Now, we correctly call SetFileTypes to set the filter
			hr = p_file_open->SetFileTypes(static_cast<UINT>(filterSpecs.size()), filterSpecs.data());
			if (FAILED(hr))
			{
				// If it failed, we break the loop
				break;
			}
		}

		// Show the dialog
		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;

		// Retrieve the selected items
		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;

		// Iterate over the selected items and add their paths to the vector
		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))
				{
					if(!files.has_value())
					{
						files.emplace();
					}
					files->emplace_back(path);				
					CoTaskMemFree(path);
				}
				p_item->Release();
			}
		}

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

	if (p_file_open)
		p_file_open->Release();
	CoUninitialize();
	return  files ;
}

GetExistingDirectorys函数定义如下：

std::optional<std::vector<std::wstring>> GetExistingDirectorys(const std::wstring& dialogTitle, bool multiSelect)
{
	IFileOpenDialog* p_file_open = nullptr;
	bool are_all_operation_success = false;
	std::optional<std::vector<std::wstring>> paths;
	while (!are_all_operation_success)
	{
		// Create the file dialog instance
		HRESULT hr = CoCreateInstance(CLSID_FileOpenDialog, NULL, CLSCTX_ALL,
			IID_IFileOpenDialog, reinterpret_cast<void**>(&p_file_open));
		if (FAILED(hr))
			break;

		// Set dialog title if specified
		if (!dialogTitle.empty())
		{
			hr = p_file_open->SetTitle(dialogTitle.c_str());
			if (FAILED(hr))
				break;
		}

		// Handle folder selection and multi-select options
		if ( multiSelect)
		{
			FILEOPENDIALOGOPTIONS options = 0;
			hr = p_file_open->GetOptions(&options);
			if (FAILED(hr))
				break;			
					
		    options |= FOS_ALLOWMULTISELECT|FOS_PICKFOLDERS;
			hr = p_file_open->SetOptions(options);
			if (FAILED(hr))
				break;
		}	

		// Show the dialog
		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;

		// Retrieve the selected items
		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;

		// Iterate over the selected items and add their paths to the vector
		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))
				{
					if(!paths.has_value())
					{
						paths.emplace();
					}
					paths->emplace_back(path);
					CoTaskMemFree(path);
				}
				p_item->Release();
			}
		}

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

	if (p_file_open)
		p_file_open->Release();
	CoUninitialize();

	return paths;

}

//使用例子：
std::wstring dialogTitle = L"选择资料的文件夹";	
if (auto selectedPaths = GetExistingDirectorys(dialogTitle, true); selectedPaths.has_value())
{
	for (const auto& dir : selectedPaths.value())
	{
		 ...
	}				
}

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