UWP，C++/Cx文件OpenPicker

有人知道我在这方面做错了什么吗

    // STORAGE FILE
    StorageFile^ saveFile;

    // FILE PICKER, FOR SELECTING A SAVE FILE
    FileOpenPicker^ filePicker = ref new FileOpenPicker;

    // ARRAY OF FILE TYPES
    Array<String^>^ fileTypes = ref new Array<String^>(1);
    fileTypes->Data[0] = ".txt";

    filePicker->ViewMode = PickerViewMode::Thumbnail;
    filePicker->SuggestedStartLocation = PickerLocationId::Desktop;
    filePicker->FileTypeFilter->ReplaceAll(fileTypes);

    // THIS SHOULD HOPEFULLY LET US PICK A FILE

    saveFile = filePicker->PickSingleFileAsync();

我得到以下错误

错误C2440:“=”：无法从“Windows:：Foundation:：IAsyncOperation^”转换为“Windows:：Storage:：StorageFile^”

错误C2440:“=”：无法从“Windows:：Foundation:：IAsyncOperation^”转换为“Windows:：Storage:：StorageFile^”

PickSingleFileAsync是异步方法，返回类型为Windows:：Foundation:：IAsyncOperation，无法转换为StorageFile类型。正如Hans Passant所说，您可以使用create_任务来等待这个异步操作

create_task(folderPicker->PickSingleFolderAsync()).then([this](StorageFolder^ folder)
{
    if (folder)
    {
        //do some stuff
    }
    else
    {
        //do some stuff
    }
});

---

有关更多信息，请参阅。

您必须等待任何异步操作。使用create_task或co_wait extension关键字。这里有很多示例代码。您也可以将文件类型附加到现有的向量中-您不必用自己的数组替换内容。

create_task(folderPicker->PickSingleFolderAsync()).then([this](StorageFolder^ folder)
{
    if (folder)
    {
        //do some stuff
    }
    else
    {
        //do some stuff
    }
});