An exception of type 'System.ArgumentNullException' occurred in Microsoft.WindowsAzure.Storage.dll but was not handled in user code

Question

I'm trying to connect to Azure media storage to upload files but I get the error every time I try to upload a file.

The error arises in the following section of the code:

var container = CloudStorageAccount.Parse(
            ConfigurationManager.AppSettings["StorageConnectionString"]).CreateCloudBlobClient()
            .GetContainerReference(ConfigurationManager.AppSettings["StorageContainerReference"]);

The application settings is as follows:

  <appSettings>
    <add key="webpages:Version" value="2.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="PreserveLoginUrl" value="true" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
    <add key="StorageConnectionString" value="DefaultEndpointsProtocol=https;AccountName=mediasvczfpr6c9dg9jx2;AccountKey=+DlbXTjZG7bni9LOKaYOxqsxBxXVmzh7BpPzWByBi/Csl9XZ+VRcqMbZxuwcbDIg88o73+6M9ByVLwsHNNyLKQ==" />
    <add key="CloudStorageContainerReference" value="temporary-media" />
    <add key="StorageAccountKey" value ="+DlbXTjZG7bni9LOKaYOxqsxBxXVmzh7BpPzWByBi/Csl9XZ+VRcqMbZxuwcbDIg88o73+6M9ByVLwsHNNyLKQ==" />
    <add key="StorageAccountName" value="mediasvczfpr6c9dg9jx2" />
    <add key="MediaAccountName" value="azurevideoportal" />
    <add key="MediaAccountKey" value="T2yMBqN0mk2O//cX+5RMYhqWOS3ekd0RJ3bLtTO5TgI=" />
  </appSettings>

I fail to see why it won't connect to my azure storage since I'm using the same connection for a different project where it works fine.

The container variable is returned a null value so the error says:

Additional information: Value cannot be null.

Answer 1

This is just a simple variable naming error :)

In your line of code that's causing the exception, you are referencing the variable StorageContainerReference from your Web.config file. However, in your Web.config file, the variable is named CloudStorageContainerReference .

Try this instead, and it should help:

<appSettings>
    <add key="webpages:Version" value="2.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="PreserveLoginUrl" value="true" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
    <add key="StorageConnectionString" value="DefaultEndpointsProtocol=https;AccountName=mediasvczfpr6c9dg9jx2;AccountKey=+DlbXTjZG7bni9LOKaYOxqsxBxXVmzh7BpPzWByBi/Csl9XZ+VRcqMbZxuwcbDIg88o73+6M9ByVLwsHNNyLKQ==" />
    <add key="StorageContainerReference" value="temporary-media" />
    <add key="StorageAccountKey" value ="+DlbXTjZG7bni9LOKaYOxqsxBxXVmzh7BpPzWByBi/Csl9XZ+VRcqMbZxuwcbDIg88o73+6M9ByVLwsHNNyLKQ==" />
    <add key="StorageAccountName" value="mediasvczfpr6c9dg9jx2" />
    <add key="MediaAccountName" value="azurevideoportal" />
    <add key="MediaAccountKey" value="T2yMBqN0mk2O//cX+5RMYhqWOS3ekd0RJ3bLtTO5TgI=" />
  </appSettings>

Answer 2

From this line in your code

var container = CloudStorageAccount.Parse(
        ConfigurationManager.AppSettings["StorageConnectionString"]).CreateCloudBlobClient()
        .GetContainerReference(ConfigurationManager.AppSettings["StorageContainerReference"]);

I dont see anything in your AppSettings called StorageContainerReference . From the Azure docs themselves I see something like this as being the right way Link to Azure Docs

// Retrieve storage account from connection string.
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString"));

// Create the blob client.
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

// Retrieve a reference to a container.
CloudBlobContainer container = blobClient.GetContainerReference("ContainerName");

From your example could be because theres no settings by the name given or could be a fult in the StorageConnectionString setting