Azure Blob Storage Object reference not set to an instance of an object

Question

  public class StorageService
    {
        CloudStorageAccount storageAccount = CloudStorageAccount.Parse("DefaultEndpointsProtocol=https;AccountName=leepiostorage;AccountKey=removed for this post");

        public async Task Upload(string id, Stream data)
        {
            CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
            // Retrieve a reference to a container.
            CloudBlobContainer container = blobClient.GetContainerReference("images");

            await container.CreateIfNotExistsAsync();

            container.SetPermissions(
                new BlobContainerPermissions
                {
                    PublicAccess = BlobContainerPublicAccessType.Blob
                }); 


            CloudBlockBlob blockBlob = container.GetBlockBlobReference(id);

            await blockBlob.UploadFromStreamAsync(data, data.Length);
        }

        public async Task UploadBlogPhoto(string id, Stream data)
        {
            CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
            // Retrieve a reference to a container.
            CloudBlobContainer container = blobClient.GetContainerReference("mycontainer");

            await container.CreateIfNotExistsAsync();

            container.SetPermissions(
                new BlobContainerPermissions
                {
                    PublicAccess = BlobContainerPublicAccessType.Blob
                });


            CloudBlockBlob blockBlob = container.GetBlockBlobReference(id);

            await blockBlob.UploadFromStreamAsync(data, data.Length);
        }
    }

Here is my StorageServices class where I am trying to make use of the second method, "UploadBlogPhoto". The first one works.

Here is the blog controller's method:

[HttpPost]
        public async Task<ActionResult> UploadPhoto(HttpPostedFileBase file)
        {
            if (file != null && file.ContentLength > 0)
            {
                var fileExt = Path.GetExtension(file.FileName);
                if (fileExt.ToLower().EndsWith(".png") || fileExt.ToLower().EndsWith(".jpg") ||
                    fileExt.ToLower().EndsWith(".gif"))
                {
                    var str = "example";
                    await service.UploadBlogPhoto(str, file.InputStream);
                }
            }
            return RedirectToAction("Index");
        }

The view with the script:

 @using (Html.BeginForm("UploadPhoto", "Blog", FormMethod.Post, new { enctype = "multipart/form-data" }))
            {
                <div class="browseimg">
                    <input type="file" class="display-none" name="file" id="files" onchange="this.form.submit()" />
                </div>
            }
            <button class="btn btn-primary width-100p main-bg round-border-bot" id="falseFiles">
                Upload billede
            </button>

 $(document)
       .ready(function () {
           $('#falseFiles')
               .click(function () {
                   $("#files").click();
               });
       });

So the first method uploads to a container called "images" just fine. When I try to simply add another method that uploads to a second container, I get

Object reference not set to an instance of an object.

at

await service.UploadBlogPhoto(str, file.InputStream);

I've triple checked everything, any ideas? Thanks in advance

Yes it does and file.InputStream gets the image succesfully. — crystyxn
The error says that the exception is at service.UploadBlogPhoto but if a breakpoint inside that method is being hit, you should be able to pinpoint the exact line by using F10 a few times once you're debugging inside UploadBlogPhoto. — sachin
Doesn't seem to do anything else. After that line it goes straight to the error? — crystyxn
hmm, BTW, you could create just one method instead of 2 in StorageService and pass a third string parameter for the Container name. — sachin

crystyxn crystyxn · Accepted Answer · 2016-10-03T11:25:09

The problem was the service was not initialized in the BlogController.

Simply adding a

public BlogController()
        {
            service = new StorageService();
        }

fixed my problem

Azure Blob Storage Object reference not set to an instance of an object

1 Answers