从 Azure Blob 存储下载图像

Question

我正在编写一个程序，可以从我们的 Azure 存储容器中的指定文件路径下载图像。

我从网上找到的代码中整理了以下功能，然后删除了错误。但是，我无法摆脱的最终错误。

完整代码如下：

using System;
using System.Windows.Forms;
using Microsoft.WindowsAzure.Storage;

using Microsoft.WindowsAzure.Storage.Blob;
using System.IO;
namespace WarehousePhotoProgram
{
    public partial class Form1 : Form
    {
        string storageConnectionString = Environment.GetEnvironmentVariable("storageconnectionstring");

    public Form1()


       {
            InitializeComponent();
        }

        private void DownloadFileFromBlob(string fileName, string containerName)
        {
            CloudStorageAccount account = CloudStorageAccount.Parse(RoleEnvironment.GetConfigurationSettingValue(storageConnectionString));
            CloudBlobClient blobClient = account.CreateCloudBlobClient();
            CloudBlobContainer container = blobClient.GetContainerReference(containerName);
            CloudBlob blob = container.GetBlobReference(fileName);
            MemoryStream memStream = new MemoryStream();
            blob.DownloadToStream(memStream);
            Response.ContentType = blob.Properties.ContentType;
            Response.AddHeader("Content-Disposition", "Attachment; filename=" + fileName.ToString());
            Response.AddHeader("Content-Length", blob.Properties.Length.ToString());
            Response.BinaryWrite(memStream.ToArray());

        }
    }
   }

代码当前在 RoleEnvironment 上出错，提示名称空间不存在，我是否缺少程序集引用？或者我需要导入另一个 using。第二个错误是所有 Result. 再次指出 Response 不存在。

这也是从 BlobStorage 下载图像的最佳方法吗？还是我应该采用其他方法？

编辑：我在给定答案的帮助下解决了 RoleEnvironment 错误。现在尝试确定代码的响应部分也需要更改。

        public Form1()
    {
        InitializeComponent();
        //_storageAccount = CloudStorageAccount.Parse(storageConnectionString);

        DownloadFileFromBlob("029000/1.png", "warehouseimages", "Desktop");
    }

    private void DownloadFileFromBlob(string fileName, string containerName, string localFilePath)
    {
        CloudStorageAccount account = CloudStorageAccount.Parse(storageConnectionString);
        CloudBlobClient blobClient = account.CreateCloudBlobClient();
        CloudBlobContainer container = blobClient.GetContainerReference(containerName);
        CloudBlob blob = container.GetBlobReference(fileName);
        using (var fileStream = System.IO.File.OpenWrite(localFilePath))
        {
            blob.DownloadToStream(fileStream);
            MessageBox.Show("SUCCESS");
        }
    }

Answer 1

RoleEnvironment class 是 Microsoft.WindowsAzure.ServiceRuntime 命名空间的一部分，我从旧的 classic 云服务中了解到它。

您可能应该使用 ConfigurationManager 来检索您的设置。

见Configuration in ASP.NET Core or if you use the .NET full framework read more about it here。

Answer 2

如果你想下载图片到本地磁盘，你的代码可以修改如下：

    /// <summary>
    /// Download File From Blob
    /// </summary>
    /// <param name="fileName">For example: image.PNG</param>
    /// <param name="containerName">container name of blob</param>
    /// <param name="localFilePath">For example: @"C:\Test\BlobTest.PNG"</param>
    private void DownloadFileFromBlob(string fileName, string containerName, string localFilePath)
    {
        CloudStorageAccount account = CloudStorageAccount.Parse("Your connection string");
        CloudBlobClient blobClient = account.CreateCloudBlobClient();
        CloudBlobContainer container = blobClient.GetContainerReference(containerName);
        CloudBlob blob = container.GetBlobReference(fileName);
        using (var fileStream = System.IO.File.OpenWrite(localFilePath))
        {
            blob.DownloadToStream(fileStream);
        }
    }

从 Azure Blob 存储下载图像

Downloading images from Azure Blob Storage

c#

blob

memorystream

azure

azure-blob-storage