XOJO FOCUS SET CONTROL CODE

To quickly create a property, you can enter both its name and type on one line in the Name field like this: PropertyName As DataType. You can set the property name, type, default value and scope using the Inspector.

XOJO FOCUS SET CONTROL CODE

To add a property to a class, use the Add button on the Code Editor toolbar, Insert ↠ Property from the menu, the contextual menu or the keyboard shortcut (Option-Command-P on macOS or Ctrl+Shift+P on Windows and Linux). Properties are variables that belong to an entire class instance rather than just a single method. But they can also contain many other thing such as constants, enumerations, events and structures. Like modules, classes primarily contain properties and methods. Use the Inspector to change the name of the class. This adds a new class to the Navigator with the default name (Class1 for the first class). To add a new class, click the Insert button on the toolbar and choose Class or select Class from the Insert menu. In Xojo, adding a class to a project is easy. Changes to one do not affect the other as you can see in these diagrams: When you do it this way, you get two separate instances. This is an example of a Vehicle class that will be used in later examples:Įnter fullscreen mode Exit fullscreen mode Because each button is a separate instance, this is what allows you to have multiple buttons on a window, with each button being completely independent of each other with its own settings and property values. But each time you add a control class to a layout (such as a window, web page or view) you get an instance of the class. Xojo has many built-in classes for user interface controls such as PushButton, WebButton, iOSButton, Label, WebLabel, iOSLabel, TextField, WebTextField, iOSTextField, ListBox, WebListBox and iOSTable to name just a few.īy themselves, control classes are not all that useful they are just abstract templates. Each instance (also called an object) is a separate and independent copy of the class and all its methods and properties. Unlike a module, which exists only once in your application, a class can have multiple instances. The Reference: Classes provide better code reuse because of a concept called instances.But unlike a module, a class can have multiple instances that each contain different data. And like a module, each class exists in your project only once. The Class: Think of the class as a template for a container of information (code and data), much like a module.Understanding Classes, Instances and Referencesīefore you can use a class in your project, it is important to understand the distinction between these three concepts: the class itself, the instance of the class and the reference to the class. And with classes, you have the option to create versions that don’t allow access to the source code of the class, allowing you to create classes you can share or sell to others. You can use classes to create custom controls. More Control: Classes give you more control than you can get by simply adding code to the event handlers of a control in a window.The less code you have, the less code there is to debug. Changes to the code in a class are automatically used anywhere where the class is used. By storing one copy of the code, when you need to make changes, you'll spend less time tracking down all those places in your project where you are using the same code. If you have basically the same code copied in several places of your application, you have to keep that in mind when you make changes or fix bugs.

Easier Code Maintenance: Less code means less maintenance.

Smaller Projects and Applications: Because classes allow you to store code once and use it over and over in a project, your project and the resulting application is smaller in size and may require less memory.

If you create a class based on the PushButton control and then add your code to that class, any usage (instances) of that custom class will have that code. If you want to use the same code with another PushButton, you need to copy the code and then make changes to the code in case it refers to the original PushButton (since the new PushButton will have a different name than the original).Ĭlasses store the code once and refer to the object (like the PushButton) generically so that the same code can be reused any number of times without modification.

Reusable Code: When you directly add code to a PushButton on a Window to customize its behavior, you can only use that code with that one PushButton.

Classes are the fundamental building blocks of object-oriented programming. But unlike a module, a class provides better code reuse. In its simplest form, a class is a container of code and data much like a module.

Xojo focus set control