Features

Microsoft Azure Storage is a low-cost option that allows storing binary content in the cloud. Let’s implement storing of product pictures in the Northwind sample database. We will capture name, size, and content type of the picture file in the Products table. The actual pictures will be saved in Microsoft Azure Storage.

Setting Up Azure Storage

Navigate to http://azure.com and click on the Portal link in the top right corner to log in to your Azure account. If you do not have an account, a free three month trial is offered.

When the Management tool loads, click on the New button in the bottom left corner. Select Data Services | Storage | Quick Create option. Assign a URL for your new storage and press Create Storage Account.

When complete, click on the new storage account name in the list to view details. On the action bar displayed at the bottom, press Manage Access Keys. Copy one of the keys into the clipboard.

At the top of the form, click on Containers tab. Press Add Container at the bottom of the screen.

Assign a name to the container. If you do not expect the product pictures to be accessible to anonymous users, then leave Access property as “Private”. Click on the Check icon to save.

Adding Utility Fields to the Database

Start SQL Server Management Studio. In the Object Explorer, right-click on Databases / Northwind / Tables / dbo.Products, and press Design.

Add the following columns:

Save the changes. Switch to the generator and click on the project name. Select Refresh, check the box next to Products controller, and proceed to refresh the web app.

Configuring BLOB Field

Start the Project Designer. In the Project Explorer, switch to the Controllers tab. Right-click on Products / Fields node, and press New Field.

Assign the following properties:

Save the field. Drag the new field node and drop it onto Products / Views / editForm1 to instantiate the field as a data field in the editForm1 view.

Drag the field onto view grid1 to display the picture in the list of products.

Next, double-click on the Products controller node. Enter the following in BLOB Adapter Configuration.

Note that the values above are not functional. Replace the highlighted parts with your own settings.

Make sure to save the controller.

Viewing the Results

On the toolbar, press Browse. Navigate to the Products page, and edit any record. Note that there is a Picture field which accepts files. Click on the link to upload a file and select a picture from your hard drive. A bar at the top of the page will announce completion of upload and the thumbnail of the picture will be displayed. The utility fields will be updated with the picture file name, length, and content type. If you do not want users to change any utility field values, configure the data fields as Static.

The thumbnail will display the file extension if the file is not an image.

The uploaded files are visible in Azure Management screen.

To upload files larger than 4 MB, you will need to increase the application upload size limit.

Starting with release 7.0.7.0, web applications created with Premium or Unlimited edition include a preview of the second generation data sheet view. The new implementation supports horizontal and vertical scrolling, column resizing, and freezing. In addition, applications based on Microsoft SQL Server or Oracle also support hierarchical presentation of data.

The preview does not yet support all capabilities available in the original data sheet. The missing features will be released as soon as they become production-ready. Therefore, the second generation data sheet is disabled by default. If you would like to take it for a spin, make sure to regenerate your web app and follow the instructions below.

Start the web application generator. Create a sample Northwind web app. When generation is complete, click on the project name in the start page of the generator. Then, click Develop to open the project in Visual Studio.

In the Solution Explorer, right-click on ~\App_Code folder, and press Add | Add New Item…

Select Class from the list, and assign a name. Press Add to create the file.

Replace the existing code base with the following:

C#:

namespace MyCompany.Data
{
    public partial class ControllerUtilities
    {
        public override bool SupportsScrollingInDataSheet
        {
            get { return true; }
        }
    }
}

Visual Basic:

Namespace MyCompany.Data
    Partial Public Class ControllerUtilities
        Public Overrides ReadOnly Property SupportsScrollingInDataSheet As Boolean
            Get
                Return True
            End Get
        End Property
    End Class
End Namespace

Save the file and run the web app. Navigate to the Customers page. On the action bar, press Action | Show in Data Sheet.

The grid view will render the second generation data sheet.

The second generation data sheet will be enabled by default when the feature set of the previous implementation is replicated.

To use the original data sheet view implementation, make sure that the SupportsScrollingInDataSheet property of class ControllerUtilities returns false.