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Customizing Entity Fields in LightSwitch

In this lesson, you’ll learn how to set properties and change the data type for fields in a data entity in LightSwitch.

By setting the Summary Property for an entity, you specify the field that is used to describe the entity type when used on screens. For example, the default Summary Property for the Contacts entity is the Id field. In this case it’s better to set the Summary Property to a field with a more meaningful name. such as CompanyName.

To set the summary property

  1. In Solution Explorer, open the shortcut menu for the Customers.lsml node, and then choose Open.

    The Data Designer opens.

  2. On the Perspective bar, choose the HTMLClient tab.

  3. In the Properties window, in the Summary Property list, choose CompanyName.

By setting display properties, you specify how the data for a given field appears to the user. For example, for a field named CompanyName you might want to display it to the user as simply “Company”.

To change a display name

  1. In the Data Designer, choose the CompanyName field.

  2. In the Properties window, choose the Display Name property, and then enter Company in the text box.

By setting the Description property for a field you can provide text that is displayed to the user as a tooltip in the running application.

To set the description property

  1. In the Data Designer, choose the ContactName field.

  2. In the Properties window, choose the ContactName property text box and enter This is our primary contact at this company.

    The value of the Description property appears as a tooltip in the application when a user points to a field.

Fields in a database table are often stored in a format that's efficient for the database but may not be what you want to display to the user. For example, fields that represent monetary values are typically stored as a Decimal data type,. For display purposes, you would usually want to format the values with a currency symbol and the correct number of decimal places.

To change data types

  1. In Solution Explorer, open the shortcut menu for the Customers node, and then choose Open.

  2. In the Data Designer, on the Perspective bar, choose the Server tab.

  3. In the Properties window, choose the ContactName property text box and enter This is our primary contact at this company.

    The value of the Description property appears as a tooltip in the application when a user points to a field.

  4. In the Type column, open the list, and then choose PhoneNumber.

    PhoneNumber is a custom business type that displays a telephone number in a standardized format. You can specify the valid formats for your application by choosing the Phone Number Formats property.

  5. In Solution Explorer, open the shortcut menu for the Order_Details node, and then choose Open.

  6. In the Data Designer, on the Perspective bar, choose the Server tab.

  7. Choose the UnitPrice field.

  8. In the Type column, open the list, and then choose Money.

    Money is another custom business type for formatting and displaying currency values.

  9. In the Properties window, choose the Currency Symbol property and enter $ in the text box.

  10. Choose the Decimal Places property and enter 2 in the text box.

In this lesson, you set properties for entity fields and you changed the data type of a field. It's good practice to customize display properties and data types immediately after you add an entity, but you can do this at any time during application development.

The first property that you set was the Summary property. For screens that contain lists, this field appears in the list instead of the default ID field.

Database field names can’t contain spaces, and sometimes use an underscore character to represent a space. To ensure that the field names displayed to your users are clear and easy to understand, you can revise the field names and add spaces in LightSwitch. To do this, review the field names in your database entities, and change the Display Name property for any fields that require a better display name.

Most of the properties that you can set are related to appearance, but others set validation rules and other characteristics. Availability of properties varies by data type. Later lessons describe other properties.

By using a custom data type, you can present data in a way that's most appropriate for your application without changing a type in the underlying database. For example, the Money custom type converts the decimal format in the database to a currency format in the display, while the database retains its efficient decimal format. Many custom data types provide type-specific properties. For example, the Currency Symbol property for the Money type determines how currency is displayed to users.

In addition to the PhoneNumber and Money custom business types, LightSwitch also provides the EmailAddress, Hyperlink, Percentage, Web Address, and Image types.

Note Note

Images are often stored in a database as a Binary data type. You can't display a Binary type, but you can change it to the Image type for display purposes.

In the next lesson, you’ll learn how to present a list of predetermined values to the user. Next lesson: Presenting a List of Choices in a LightSwitch Application

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