With this template you can add a new Date Picker component to your project. Date Picker allows the user to select the day, month and year from three lists the user can conveniently scroll. The special case of leap year is handled automatically. Each time the user interacts with the picker, the component sends signals to associated slot methods where your particular implementation is executed.

Components created with this template are intended to be adapted to your particular design expectations. After adding the new Date Picker you should edit the component, change its appearance and if desired also its behavior. Once you have adapted the component, you can embed instances of this Date Picker wherever you need in your GUI project. Because it serves as template, it is intentionally kept very simple. Nevertheless, Date Pickers created by the template are working widgets. If desired, they can already be used as they are. The following figure demonstrates the default appearance of the Date Picker created by using the here described component template:

The approach with component templates has two functions. Primarily the templates should simplify the development of new components. Instead of creating the Date Picker from scratch you can use the available template. The second function is more educative. The template implements fully working Date Picker component you can investigate and learn about the corresponding programming aspects. The template is well documented. It contains annotations and inline comments with instructions helping you to understand how the component works and how it can be adapted to your particular needs.

This chapter provides an overview how the Date Picker component template is used within your own application and how you adapt this component according to your particular needs. You will find here also further details concerning the internal implementation of the Date Picker component.

To create a new Date Picker component from a template you simply Drag & Drop it between the Templates window and the Composer with an opened unit. This is important in that by using the component templates you add in fact a new class to your project. Classes, in turn, can exist within units only. The following are the typical steps to create a new Date Picker component from a template:

The new created Date Picker component appears accompanied by annotation providing helpful tips how to proceed. If undesired, you can select and delete the annotation.

Once you have created the Date Picker component, you can use it to assemble more complex components. Technically seen, you embed an instance of the Date Picker class in-place within some superior GUI component. At the runtime, the superior GUI component takes care of the correct initialization and the displaying of all embedded components, so they appear similarly as you have composed them at the design time.

The following are the typical steps to create a new instance of an already existing Date Picker component:

As long as the Date Picker is selected you can inspect and modify its properties conveniently in the Inspector window as demonstrated with the property Bounds in the screenshot below. This is in so far worth mentioning as diverse features of the Date Picker are controlled by the corresponding properties. If you are not familiar with the concept of a property and the usage of Inspector window, please read first the preceding chapter Compositing component appearance.

The Date Picker component descends from the Mosaic class Core::Group. Consequently, most of the properties listed in the above screenshot are inherited from this base class. Particular to the Date Picker are only few following properties:

Property	Description
Day	The property Day stores the day of the month. The valid value lies in range 1 .. 31 depending on the actually selected month.
Month	The property Month stores the month of the year. The valid value lies in the range 1 .. 12.
OnChange	The property OnChange can refer to a slot method, which will receive a signal each time the user selects another date. Thereupon the method's logic will be executed. In the associated slot method you can evaluate the date picker properties Day, Month and Year.
Year	The property Year stores the year. The value is valid in range 1900 .. 2100.

Once added to the component, you can freely move the Date Picker instance, or you simply grab one of its corners and resize it in this way. You can control the position and the size of the component also by directly modifying its property Bounds. If you want the Date Picker to appear behind other views you can reorder it explicitly.