Rajeev Pentyala – Technical Blog on Power Platform, Azure and AI

In one of my previous articles, I detailed the steps to embed a Canvas app with upload image to Azure Blob feature.

In this article lets see, how to work with large data sets and achieve following:

• Displaying blob images in Gallery.
• Ability to Download the image.

Pre-requisites:

• Azure Storage Account and Container. Get free Azure subscription here
• Dynamics 365 account. Get 30 days trail here

Set up Azure Storage Account and Container

• Connect to your Azure portal.
• Create a new Storage Account and capture the Storage Account ‘Name’ and ‘Access Key’.
  • I’ve named Storage Account name as ‘expmar’

• Create a new Container and copy the Name.
  • I named my Container as ’employee’.

• Upload few images, which will be used to display in Canvas App.

Steps to create Canvas App and Connect to Azure Blob

Create Azure Blob Storage Connection:

• Connect to Power Apps Portal using your Dynamics 365 account.
• To connect to Azure Storage Account from Canvas App, we need a new ‘Azure Blob Storage’ Connection.
• Click on ‘Data -> Connections -> Azure Blob Storage’ and provide Azure Storage Account ‘Name’ and ‘Access Key’ captured in previous section and click ‘Create’.

• Up on successful creation, you should see the ‘Azure Blob Storage’ under ‘Connections’.

Steps to Create Canvas App and display blob images

• Create a new Canvas App.
• Add the ‘Azure Blob Storage’ connection created in previous step to the Canvas App from ‘Data -> Add a connection’.

• As we established connection to Azure Storage Account, next, connect to ‘Container’ (i.e., Employee) and read the images to a List.
• Use following formula on App’s ‘On Start’ event.

• This formula, reads the images from ’employee’ Container and store the images in ’employeePhotos’ Collection.
• Now we have the images in ’employeePhotos’ Collection, add a Gallery control and bind to ’employeePhotos’ Collection.

• To display images, In the Gallery, add an ‘Image’ control and in the ‘Image’ property add following formula.

• To display image name, add a ‘Label’ control and set Text as ‘ThisItem.DisplayName’.

• To check whether images are rendering click on ‘App -> Run OnStart’ and you should see the images upload to Azure Blob Container in the Gallery.

Steps to Build Download feature

• To download an image from Azure Container, we would need following 2 values:
  • URL : Azure Storage Account URL.
    • URL format would be “https://{Storage Account Name}.blob.core.windows.net“
    • In my case, its “https://expmar.blob.core.windows.net”
  • SasToken (Shared access signature Token):
    • Generate the ‘Shared access signature’ as below from Azure portal.

• Set ‘URL’ to ‘bloburl’ and ‘Token’ to ‘sastoken’ variables ‘OnStart’ of the App.
• Complete ‘OnStart’ formula looks as below.

• Add a ‘Download’ icon to the Gallery.

• On ‘OnSelect’, use ‘Download(bloburl & ThisItem.Path & sastoken)’ formula.

Test the App

• Run the App and you should see Images and ‘Download’ icon as below.

• Click on ‘Download’ icon and image should get downloaded.

🙂