Blog: Posts from April, 2012

The following screen shows  a customer record from the Northwind sample presented in edit mode. Suppose that you want to add a button to the form to automatically calculate certain field values.

Start the web application generator and select your project. Click Design to activate the Project Designer.

Activate Controllers tab in the Project Explorer and right-click Customers / Actions / ag2 (Form) node. Choose New Action option to create a new action.

Enter the following properties.

select
  @CompanyName = @CompanyName +  '+',
  @ContactName = @ContactName + '-'

Save the action and click Browse on the Designer toolbar.

Your web application will be displayed in the default web browser. Navigate to the Customers page and start editing any record.

You will notice the Calculate Values button displayed above and below the form fields. Click the button and you will see “+” added to the Company Name field and “-” added to the Contact Name field.

If you press Calculate Values button a few more times then you will see more “+” and “-” characters added to the same fields.

If you cancel the changes then the record will not be updated.

The changes made by SQL action will be persisted if you click OK button.

Action SQL causes the client library to send the current field values to the server. The core application framework knows how to handle this action.

First, the framework will find the text entered in the “Data” property of the action.

Next, it will parse the text to detect any parameters.

If you database server uses another symbol to indicate a parameter, then make sure to enter this symbol instead of “@”.

If the parameters are found then the framework will try to match them to the names of the available data fields. The application will also recognize parameters that have “_Value”, “_NewValue”, and “_OldValue” suffix. If there is a matching data field then the field’s current, new, or old value will be assigned to the parameter.

All parameters are marked as Input/Output parameters.

The application will execute the SQL text. If any parameter values have changed, then they will be packaged and sent back to the client. The client library will reflect the changed values in the user interface as if the application user has entered them in the input text boxes.

It is expected that the SQL text in action’s Data property contains instructions assigning values to parameters that are not matched to the fields. You can use any SQL language constructs supported by your database server as if you were executing them in a tool such as SQL Management Studio.

Consider the following sample data for SQL action:

declare @Temp nvarchar(50)

-- swap City and Country
set @Temp = @City
set @City= @Country
set @Country= @Temp

-- update Company Name
select @CompanyName = @CompanyName + ': ' + City + '/' + Country
from Customers 
where CustomerID = @CustomerID

Enter this text in the Data property of the action and click OK button.

This is the result of action execution if you browse to a customer record, start editing, and push the Calculate Values button.

If you need more than just an interaction with the database to perform a calculation, then consider using custom business rules or shared business rules for implementation. Learn more about implementing calculations with “Custom” action.

The picture below shows the  Employees editForm1 view. By default, the fields are arranged in a vertical list. The category description is at the top of the form, the field labels are in the first column, and the data fields are in the second column. When you resize the page width, the column width will change.

Let’s use the Float property on the category to change the presentation of the data fields.

Start Code On Time generator, click on the project name, and press Design. In the bottom right corner of the Project Explorer, switch to the Controllers tab. Double-click on Employees / Views / editForm1 / c1 – Employees node.

Change the Floating property to “Yes”.

Press OK to save the category. On the tool bar, press Generate. Navigate to the Employees page, and select a record. The category is now much more compact. Each field has the label above it, floating around the category. When you resize the page, the fields will be rearranged to fit.

You can use a combination of floating and non-floating categories to optimize the user interface, such as the Order Details page shown below.

Floating data field categories can serve as a quick way to make a compact user interface without much effort. If you want more control over the placement of data fields, then use custom form templates or category-level templates.