我正在尝试将 Windows Azure 存储用于我的带有移动服务的 Windows 应用商店应用程序来存储图像。我按照本指南进行了上传工作:
http://www.windowsazure.com/en-us/develop/mobile/tutorials/upload-images-to-storage-dotnet/
但是,我找不到任何有关下载文件的 Material 。我什至找不到 Windows 应用商店版本的类引用!如果有人可以指导我查看文档,我将不胜感激。
无论如何,我编写了代码,但它似乎不起作用:
public static async System.Threading.Tasks.Task DownloadUserImage(SQLUser userData)
{
var usersFolder = await GetUsersFolder();
var imageUri = new Uri(userData.ImageUri);
var accountName = "<SNIP>";
var key = "<SNIP>";
StorageCredentials cred = new StorageCredentials(accountName, key);
CloudBlobContainer container = new CloudBlobContainer(new Uri(string.Format("https://{0}/{1}", imageUri.Host, userData.ContainerName)), cred);
CloudBlockBlob blob = container.GetBlockBlobReference(userData.ResourceName);
var imageFile = await usersFolder.CreateFileAsync(userData.Id.ToString() + ".jpg", CreationCollisionOption.ReplaceExisting);
using (var fileStream = await imageFile.OpenAsync(FileAccessMode.ReadWrite))
{
try
{
await blob.DownloadToStreamAsync(fileStream);
}
catch (Exception e)
{
Tools.HandleLiveException(e);
}
}
}
此代码会导致创建空文件,但不会引发任何异常。如果我将 imageUri 的值粘贴到浏览器,它就会开始下载文件并成功完成下载。但是,由于某种原因,我的程序没有。
请问有什么帮助吗?
最佳答案
显然,我打开流的方式是错误的。这是一个修复:
public static async System.Threading.Tasks.Task DownloadUserImage(SQLUser userData)
{
var usersFolder = await GetUsersFolder();
var imageUri = new Uri(userData.ImageUri);
var accountName = "<SNIP>";
var key = "<SNIP>";
StorageCredentials cred = new StorageCredentials(accountName, key);
CloudBlobClient client = new CloudBlobClient(new Uri(string.Format("https://{0}", imageUri.Host)), cred);
CloudBlobContainer container = client.GetContainerReference(userData.ContainerName);
var blob = await container.GetBlobReferenceFromServerAsync(userData.ResourceName);
var imageFile = await usersFolder.CreateFileAsync(userData.Id.ToString() + ".jpg", CreationCollisionOption.ReplaceExisting);
using (var fileStream = await imageFile.OpenStreamForWriteAsync())
{
try
{
await blob.DownloadToStreamAsync(fileStream.AsOutputStream());
}
catch (Exception e)
{
Tools.HandleLiveException(e);
}
}
}
现在一切正常。
关于C# 从 Windows Azure 存储下载返回空文件,没有任何异常,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15836598/