As you design your ESL application, you should be thinking about the concepts that your users will use when they are thinking about and using the application. Part of this work involves determining the application objects that are in the application. Here are some sample application objects:

•Customers

•Reports

•Loans

•Invoices

•Mechanical parts

•Cars

Determine which ESL objects represent or display which application objects, the operations that can be performed on the application objects, and which of those operations you want to implement using drag and drop. You may need to add some ESL objects to represent actions that can be performed on application objects, such as creating a new invoice, printing a report, or deleting a data file. You want to end up with a list something like the following:

•An icon representing a customer can be dragged to an icon representing a printer to print a report on that customer.

•The name of a customer can be dragged from a list box or table to an icon representing a printer to print a report on that customer.

•The user can drag from a dialog box displaying a loan application to an icon representing an  outbox to send a copy of the application form to the appropriate department.

•The user can drag from an icon representing a new loan application onto a graphical region to create a new loan application.

•A color can be dragged from a color palette onto a graphical region displaying a car to select the color that a customer wants.

ESL does not directly support icon objects, but you can use small image regions to simulate them. The example in Example demonstrates this.