Compound Data Types

1. Compound Data Types Part13dbg

2. Point Good things come to those who read the textbook! See page 451 of textbook. • A Point is a simple built-in struct that stores a pair of screen coordinates. • Instantiate a Point: Point aPoint = new Point(); • Assign values: aPoint.X = 100; aPoint.Y = 200; • Or do it all at one time: Point x1 = new Point(200, 175); • Point uses integer values. • Another type of Point structure is PointF;it uses float values for the x and y coordinates.

3. Size • Size is a simple built-in struct that stores dimensions (width, height pair) in pixels. • Declare a Size:Size rectSize = new Size(); • Assign values: rectSize.Width = 100; rectSize.Height = 200; • Or do it all at one time: Size boxSize = new Size(300, 100); • Size uses integer values; SizeF uses float values for the dimensions.

4. Rectangle • A Rectangle is another simple built-in struct that stores the coordinates and sizes necessary to create a rectangle. • You can initialize a Rectangle one of 2 ways: • Assign 4 integer coordinates (x-coord, y-coord, width, height) • Point and a Size (yet another struct) (startPoint, rectSize)

5. Using Points and Rectangles • Draw and Fill methods that call for coordinate pairs also accept values stored in Points. • If dimensions of Rectangles are involved, as in DrawRectangle and DrawEllipse, • the Rectangle may be used (instead of x-coord, y-coord, width, height) • Size can be used (instead of Width, Height pairs)  UsingPoints

6. Arrays of Points • Both the DrawLines() and DrawPolygon()methods of the Graphics object require an array of points to define the vertices of their output.  PointArray

7. Alternative Way to Force Paint Event • Instead of calling the Paint event manually (and the necesssary preparation of the PaintEventArgs pea), you may mark a control or form as invalidated, which will call the Paint event. • this.Invalidate(); in the Resize or Load or Click handler of a button will cause any code in the Paint event to be executed (and thus execute any drawing code you have placed there).

8. DateTime • DateTime is a built-in struct type that has a number of methods and properties used for storing and converting time and date values. • The Now property of the DateTime object delivers the present time and date to the struct from the system clock.

9. Create a Struct of Type DateTime • Declare new struct:DateTime myDT = new DateTime(); • Get present time and date: myDT = DateTime.Now; • Extract time or date value: lblDay.Text = myDT.DayOfWeek.ToString();  DateTimeStruct

10. Generate DateTime Values with DateTimePicker Control • The DateTimePicker control furnishes a visible interface for selecting DateTime values. • Dates are selected with a perpetual calendar display. • Times and dates may be displayed in several formats. • Use the TimeSpan class to manipulate and compare times and dates.  DatePicker

11. Regions in Code • We have seen before that the region, Windows Form Designer Generated Code,is a collapsible region. • When we want to view the contents, we click the in front of region. • Tocollapsethe region, we click thein front of region.

12. Making Your Own Collapsible Regions in Code • You can make your own collapsible region in code, for example, a region for the class-level variables. • Type #region regionDescriptionabove the class-level variable declarations. • Type #endregionafter the last line of class-level variable declarations. • You will now have a user-defined region.

13. Multiple Form Applications Single Document Interface

14. Launching a Second Form • Although it is possible to design a form totally manually, adding and designing a new form to a project with the IDE is much easier. • Use the Add Windows Form… selection from the Project menu. • A new form class is added to the project.

15. Launching a Second Form • An instance of the second form must be created within the original application form. • Once the form object is created, it may be displayed by running its Show() method. • Multiple instances of the second form can be created and displayed.  SecondSDI

16. Startup Form as “Parent” • Launching a second form in this way causes the second form to depend upon the first for survival. • Closing the first form causes the second form to close as well.

17. Hiding a Form • Run the Hide() method of the original form to remove it from view prior to showing the second form. • Now the second form commands the application and can not lose focus unless it is closed. • Closing the second form leaves the original form running, but not visible.  HideParent

18. Showing a Hidden Form • We could run the Show() method of the original form from the second form—but only if the second form is aware of the first form • If we created a new instance of the first form within the second form it would be different from the original. • One way to solve the problem is to pass the identity of the original form to the second form as a constructor argument.

19. Identifying the Parent Form • If the second form has a class scope variable of type Form, the constructor can use its argument to assign the identity of the “parent” form. • This then allows the second form to run the Show() method of the “parent”.  FormConstructor

20. Multiple Form Applications Owned Forms

21. Owned Forms • Subsequent SDI forms can be launched from a startup form as Owned Forms. • Although these forms can transfer focus back to the startup form they remain on top of the startup form at all times. • Add a new form to the Owned Forms collection of the startup form by setting its Owner property to the startup form.  OwnedForms

22. Owned Forms • Potential uses for owned forms are as specialized help forms, customized “toolboxes” or overview maps. • Use an owned form when you don’t want to lose sight of a form in a multiple SDI application, even if it loses focus.

23. Multiple Form Applications Multiple Document Interface

24. MDI Forms • Standard Windows forms may exist as either MDI parents or MDI children. • MDI children may only be displayed within the client area of their parent and may not be dragged outside that client area. • Like owned forms, MDI children always remain on top of their parent form.

25. MDI Parent Forms • Any standard Windows form can be converted to an MDI parent by setting its IsMdiContainer property to True. • By convention, MDI parent forms have a dark gray client area. • Because MDI parents are intended solely as containers for other forms, they should not include controls.

26. MDI Parent Forms • Use menu items in the MenuStrip control of the MDI parent to control activities associated with displaying MDI child forms.  MDIParent

27. MDI Child Forms • Forms destined to become children of an MDI parent should be instantiated within the MDI parent class. • Any standard Windows form can become an MDI child. • Set the MdiParent property of the child instance to the parent. • Show the child form.  MDIChildren

28. MDI Child Form Menus • When an MDI Child has focus within an MDI parent form, the menustrips of the Parent and Child are merged and menuitems from both are displayed. • The merging of the menus to present a sensible display is coordinated by adjusting the MergeAction and MergeIndex properties of each menuitem. • The Visible property of the child menustrip must be set to false if you do not wish to see both parent and child menustrips.

29. The Windows Menu • By design convention the Menustrip of an MDI parent form has a Window menu item that lists the displayed child forms and indicates which has focus. • The contents of this menuitem (mnuWindow) are automatically generated by simply setting the MdiWindowListItem property of the parentmenustrip to the appropriate menuitem (mnuWindow).

30. The Window Menu • Three different modes of display are available for child forms: cascade, horizontal tile, and vertical tile. • These modes can be set with the LayoutMdi() method of the parent form. • Use the foreach loop to close all forms in the child collection of the parent at once.  MDIWindows