在Windows Store应用程序的“我的图片”中创建子文件夹 [英] Create sub folders in My Pictures from Windows Store application

问题描述

我正在尝试通过Windows应用商店应用在我的图片文件夹中创建文件夹结构。但我似乎无法通过第一级。

I'm trying to create a folder structure within My Pictures folder from a Windows store app. But I can't seem to get pass the first level.

我使用以下代码创建第一级文件夹：

I create my first level folder using the following code:

IAsyncOperation<StorageFolder> appFolder = Windows.Storage.KnownFolders.PicturesLibrary.GetFolderAsync("AppPhotos");

if (appFolder==null)
{
    //Create folder
    appFolder = Windows.Storage.KnownFolders.PicturesLibrary.CreateFolderAsync("AppPhotos");
}

现在，我想在此调用Level1下创建另一个文件夹。

Now I want to create another folder below this call Level1.

我期望能够执行以下操作：

I was expecting to be able to do the following:

appFolder.CreateFolderAsync("Level1");

但是我的appFolder中没有CreateFolderAsync方法。

But I don't have a CreateFolderAsync method from my appFolder.

那么，如何创建该文件夹，然后再选择它呢？

So, how can I create that Folder and then how would I then select it?

预先感谢

我正在使用Visual Studio 2012，C＃4.5，XAML，并且正在编写Windows商店应用。

I'm using Visual Studio 2012, C#4.5, XAML and I'm writing a windows store app.

推荐答案

您似乎错过了那里的异步/等待革命，并假设获取文件夹的操作是一个文件夹。这应该起作用：

You seem to have missed the async/await revolution there and assume the operation to get a folder is a folder. This should work:

var appFolder = await Windows.Storage.KnownFolders.PicturesLibrary.GetFolderAsync("AppPhotos");

if (appFolder == null)
{
    //Create folder
    appFolder = await Windows.Storage.KnownFolders.PicturesLibrary.CreateFolderAsync("AppPhotos");
}

您还需要添加 async 关键字，然后如果您的方法返回的值类型为 T ，则将其更改为返回 Task< T> ，因此对于方法签名：

You also need to add the async keyword in the method signature wherever the above code is located and then also if your method returns a value of type T - change it to return Task<T>, so for method signature:

private void MyMethod()

您将其更改为

private async Task MyMethod()

，如果您当前的签名是

private bool MyMethod()

您需要做

private async Task<bool> MyMethod()

最后一种情况-您还需要更改来自的呼叫

Finally in that last case - you would need to also change your calls from

var myValue = MyMethod();

到

var myValue = await MyMethod();

等。用 async 关键字标记所有等待其他方法的调用的方法。

etc. marking all methods that make calls that await other methods with the async keyword.

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