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  Triggering Data View Refresh

Triggering Data View Refresh

Data views are only automatically refreshed by the client library when data is inserted, updated, or deleted. The user can force a refresh using the Refresh icon in the bottom right corner of every data view. In addition, the Refresh Interval property can be configured to refresh the data view based on a timer.

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Certain situations require a refresh based on different conditions. For example, suppose that there are multiple tabs displaying similar data.

Multiple tabs displaying different lists of Orders.

The user may change the value of a record in one of the views.

Order date of an order is changed.

However, when the user switches to another view showing the same record, the old value will be displayed.

The order date is not updated for the same record in a different tab.

Let’s add a custom user control that will contain some custom JavaScript. This code will refresh the data view when the tab is changed in order to ensure that the data visible to the user is always fresh.

Creating Views

Start the Project Designer. In the Project Explorer, switch to the Controllers tab. Right-click on Orders / Views / grid1, and press Copy. Right-click on Orders / Views node, and press Paste to duplicate the view.

Copying view 'grid1' of Orders controller.     image

Do this one more time to create three grid views. Double-click on Orders / Views / v100.

Copied view 'v100' of Orders controller.

Make the following changes:

Property New Value
Id OrdersToShip
Label Orders To Ship
Filter Expression
OrderDate is null

Press OK to save. Double-click on Orders / Views / v101.

Copied view 'v101' of Orders controller.

Make the following changes:

Property New Value
Id HighFreight
Label High Freight
Filter Expression
Freight > 30

Press OK to save.

Setting Up the Page

Switch to the Pages tab. On the toolbar, press the New Page icon.

Adding a page to the project.

Assign a name to the page:

Property New Value
Name Filtered Orders

Press OK to save. Drop the new Filtered Orders page node to the right of Home page node.

Dropping 'Filtered Orders' page node on the right side of 'Home' page node.     Page 'Filtered Orders' is now second in the menu.

Right-click on Filtered Orders page, and press New Container.

Adding a container to a page.

Keep the defaults and press OK to save. Right-click on the new container and press New Data View.

Adding a data view to container 'c101'.

Assign the following values:

Property Value
Controller Orders
View grid1
Tag Orders
Activator Tab
Text Orders

Press OK to save. Create another data view with the following properties:

Property Value
Controller Orders
View OrdersToShip
Tag Orders To Ship
Activator Tab
Text Orders To Ship

Create one more data view.

Property Value
Controller Orders
View HighFreight
Tag High Freight
Activator Tab
Text High Freight

Save the data view.

Adding User Control

Right-click on Filtered Orders / c101 container node, and press New Control.

Adding a new control to container 'c101'.

Next to the User Control property, click on the New User Control icon.

Creating a new user control.

Assign a name:

Property Value
Name RefreshDataView

Press OK to save the user control and insert it into the property. Press OK again to save the control.

On the toolbar, press Browse to generate the web application and user control. When complete, right-click on Filtered Orders / c101 / control1 – RefreshDataView node, and press Edit in Visual Studio.

Edit the user control in Visual Studio via the context menu option in the Project Explorer.

The custom user control file will open in Visual Studio. Replace the content after the <%@ Control %> element with the following:

<script type="text/javascript">
    Sys.Application.add_load(function () {
        $('div.TabBar td.Item').click(function () {
            var linkText = $(this).find('a').text();
            var tag = linkText;
            var dataView = Web.DataView.find(tag, 'Tag');
            if (dataView) {
                if (dataView._isBusy == false && dataView.get_isDisplayed())
                    dataView.refresh();

            }
        });
    })
</script>

Viewing the Results

Save the file, and switch to the web app open in your browser window. Navigate to the Filtered Orders page. The page will have three tabs displaying different filtered lists of orders. Note the Order Date of the first record.

Three tabs displaying different lists of orders.

Switch to the High Freight tab. Edit the first record, and change the Order Date.

Changing the Order Date of an order.

Save the change, and switch back to the first tab. Note that the data view refreshes and the updated data is displayed.

The data view has been refreshed - the record is showing the latest changes.

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