15 - Data Transfer

Abstract

The Windows environment provides a high degree of compatibility between applications and, as a result, there are several ways of transferring data between applications. It is possible for the application to communicate with another Windows application and ensure that data is updated automatically. This chapter describes two methods—dynamic data exchange (DDE) and object linking and embedding (OLE). The DDE methods create a link between the application and any other application with DDE capabilities. Both applications must be programmed for DDE. However, many of the most-commonly used applications have DDE built in, for example, Microsoft Excel, Word for Windows, and Paintbrush. The DDE conversation is started by the destination sending the WM_DDE_INITIATE message via the SendMessage function. The parameters for this message include the application and topic names. The multiple document interface (MDI) is a method for a main window to contain an undefined number of other windows. Many of the most common Windows applications use MDI. In an MDI application, the window that is to contain the other windows is called the frame window. The smaller windows are child windows.