Compound Data Types Part13dbg

2 Point 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. Good things come to those who read the textbook! See page 451 of textbook.

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. To collapse the region, we click the in 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 regionDescription above the class- level variable declarations. Type #endregion after the last line of class-level variable declarations. You will now have a user-defined region.

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

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.

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 parent menustrip 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