Question

我希望能够使用我的IsolatedStorage中的图像来修改锁定屏幕背景，但是我无法获得IsolatedStorage文件路径的正确语法来设置锁定屏幕背景。

在以下http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj206968(v=vs.105).aspx中，一旦从名为LockHelper的列表（已从PictureRepository.cs填充）中选择了一个图像，我就会在按钮单击事件中调用Recent方法它从IsolatedStorage加载图像）

private void recent_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {            
        capturedPicture = (sender as LongListSelector).SelectedItem as CapturedPicture;

        if (capturedPicture != null)
        {
            //filename is the name of the image in IsolatedStorage
            fileName = capturedPicture.FileName;
        }
    }

void setAsLockScreenMenuItem_Click(object sender, EventArgs e)
    {
        if (!String.IsNullOrEmpty(fileName)) 
        {
            //PictureRepository.IsolatedStoragePath is a string = "Pictures"                
            LockHelper("isostore:/" + PictureRepository.IsolatedStoragePath + "/" + fileName, false);  //results in FileNotFoundException
            LockHelper(PictureRepository.IsolatedStoragePath + "/" + fileName, false);  //results in ArgumentException
        }
        else
        {
            MessageBoxResult result = MessageBox.Show("You must select an image to set it as your lock screen.", "Notice", MessageBoxButton.OK);
            if (result == MessageBoxResult.OK)
            {
                return;
            }
        }
    }

调用LockHelper后，事件将继续

private async void LockHelper(string filePathOfTheImage, bool isAppResource)
    {
        try
        {
            var isProvider = Windows.Phone.System.UserProfile.LockScreenManager.IsProvidedByCurrentApplication;
            if (!isProvider)
            {
                // If you're not the provider, this call will prompt the user for permission.
                // Calling RequestAccessAsync from a background agent is not allowed.
                var op = await Windows.Phone.System.UserProfile.LockScreenManager.RequestAccessAsync();

                // Only do further work if the access was granted.
                isProvider = op == Windows.Phone.System.UserProfile.LockScreenRequestResult.Granted;
            }

            if (isProvider)
            {
                // At this stage, the app is the active lock screen background provider.

                // The following code example shows the new URI schema.
                // ms-appdata points to the root of the local app data folder.
                // ms-appx points to the Local app install folder, to reference resources bundled in the XAP package.
                var schema = isAppResource ? "ms-appx:///" : "ms-appdata:///Local/";
                var uri = new Uri(schema + filePathOfTheImage, UriKind.Absolute);

                //The Error Occurs Here!
                // Set the lock screen background image.
                Windows.Phone.System.UserProfile.LockScreen.SetImageUri(uri);

                // Get the URI of the lock screen background image.
                var currentImage = Windows.Phone.System.UserProfile.LockScreen.GetImageUri();
                System.Diagnostics.Debug.WriteLine("The new lock screen background image is set to {0}", currentImage.ToString());
            }
            else
            {
                MessageBoxResult result = MessageBox.Show("Cannot update your lock screen background at this time.", "Notice", MessageBoxButton.OK);
                if (result == MessageBoxResult.OK)
                {
                    return;
                }
            }
        }
        catch (System.Exception ex)
        {
            System.Diagnostics.Debug.WriteLine(ex.ToString());
        }
    }

Windows.Phone.System.UserProfile.LockScreen.SetImageUri(uri);方法中LockHelper发生错误。它是FileNotFoundException提及The filename, directory name, or volume label syntax is incorrect. (Exception from HRESULT: 0x8007007B)或ArgumentException。我引用的所有地方都说使用IsolatedStorage Uri应该是ms-appdata:///local/然后是IsolatedStorage文件路径（在我的例子中是Pictures / imagename.jpg），我相信我的错误在于Uri路径，但我不确定正确的语法？如果不是这个，还有其他想法吗？

Answer 1

在nokia developer处尝试此操作。希望你能找到解决方案的方法。

Answer 2

这对我有用：

const string filePathOfTheImage = "/Shared/ShellContent/shot2.jpg"; //This is where my image is in isostore

var uri = new Uri("ms-appdata:///local" + filePathOfTheImage, UriKind.Absolute);

另外，我使用WP Power Tools来跟踪我的应用存储空间。希望这会有所帮助。

如何使用IsolatedStorage在Windows Phone 8中设置锁屏背景

2 个答案: