Updating Existing Screens in a LightSwitch Application
In this lesson, you'll learn how to modify existing screens in your LightSwitch application.
This lesson builds upon the My First Application project that you developed in previous lessons. If you already have the project, open it now (in Visual Studio, on the menu bar, choose File, Open Project). Otherwise, complete the Working with Data in LightSwitch lesson series, and then return to this lesson.
In a previous lesson, Step 3: Create Screens in LightSwitch, you created a common screen set for the Contacts entity. In subsequent lessons you added ContactType and ContactState fields to the entity. Now you’ll add those fields to the existing screens.
The ContactLists screen currently shows the name, company, and phone number for each contact. You’ll replace the phone number with the contact type.
To update the browse screen
In Solution Explorer, open the shortcut menu for the BrowseContactLists.lsml node, and then choose Open.
In the center pane of the Screen Designer, choose the Contact Phone node, and on the toolbar choose the Delete button.
Expand the Add list (under the Contact Company node) and choose Contact Type.
Next you’ll add the contact type and contact state to the view screen.
To update the view screen
In Solution Explorer, open the shortcut menu for the ViewContactList.lsml node, and then choose Open.
In the center pane of the Screen Designer, expand the Add list (under the Contact Email node), and then choose Contact Type.
Expand the Add list and choose Contact State.
You can also drag a field from the left pane and drop it in the content tree in the center pane.
Next you’ll add the contact type and contact state to the ContactList screen.
To update the add/edit screen
In Solution Explorer, open the shortcut menu for the AddEditContactList.lsml node, and then choose Open.
In the center pane of the Screen Designer, select the Rows Layout | left node, and then expand the Add list and choose Contact State.
Select the Rows Layout | right node, and then expand the Add list and choose Contact Type.
As a final step you’ll update your existing contacts to include state and contact type, and then you’ll make the fields required for any new contacts.
To update the Contacts entity
Run the application. On the ContactLists screen, choose a contact. On the view screen, choose the Edit button.
In the Contact State text box, enter a two-letter abbreviation for a state.
In the Contact Type list, choose Existing Customer, and then choose the Save button.
Repeat steps 1 through 3 for each additional contact on the ContactLists screen, and then close the application.
In Solution Explorer, open the shortcut menu for the Contacts.lsml node.
In the Entity Designer, select the Required check box for the ContactType and ContactState fields.
This lesson showed how to add fields to existing screens. This is necessary whenever new fields are added to an entity. You may have noticed that the new fields automatically showed up in the left pane of the Screen Designer. It’s up to you to determine where they should appear in the content tree (the center pane).
You also updated the existing contacts to include the new fields, and then marked the fields as required in the Entity Designer. If you had marked the fields as required when you first created them, you would have run into validation errors when editing existing contacts. You can avoid these extra steps by planning ahead and adding all necessary fields to an entity before creating the screens.
In the next lesson, you’ll learn how create a screen to display orders.