Intermec PC43d IDL Smart Printing Resource Kit Developer Guide - Page 21

General Guidelines and Best Practices Because the printer is an embedded system that does not support Microsoft .NET Windows.Forms, you need to take certain considerations into account when creating your application. This section lists guidelines for developing your printer application, and includes suggestions for best practices. Limitations on Class Instantiation Classes tied to physical printer components may be instantiated once per component per application, as shown in the next table. A second instantiation of these components in an application raises an exception, or results in undefined or unstable behavior. Maximum Instances of a Class Class Communication.BluetoothListener Communication.IndustrialInterface Communication.SerialPort Communication.TcpListener Communication.USBHost Drawing PrintControl UI.Canvas UI.Keypad UI.LED Maximum Instances One One One per physical serial port One per IP port One per physical USB port One One One One One per physical LED Object Lifetime Management Although common practice in C# applications is to create objects when you need them, and then let the garbage collector clean them up after you no longer need them, some Intermec.Printer classes should be handled differently. Intermec recommends that you instantiate the following classes at application startup, and explicitly dispose them as the application exits: • Drawing • PrintControl • UI.Canvas • UI.Keypad • UI.LED IDL Smart Printing Resource Kit Developer Guide 15