1. Windows Programming Using C#
Forms Programming II

2. Contents
Menus
TreeView
TabControl
Layout
MessageBox
Drawing

3. Menus Pulldown menus provide a way to select commands and options
Normally these are in a MenuStrip across the top of the application
Begin by placing a MenuStrip across the application
It displays boxes into which menu items and cascading menus can be typed

4. Menus The type here text allows new items to be added
When you click on type here a pull down appears letting you select
Menu item
ComboBox
Separator
TextBox

5. MenuItem Properties Checked – if true displays check mark
CheckOnClick – check state changes when clicked
CheckState – one of
CheckState.Checked
CheckState.Unchecked
CheckState.Indeterminate
ShortcutKeys – a member of the Shortcut enumeration indicating the shortcut key

6. MenuItem Click – event which is raised when the menu item is clicked
Menu items are similar to buttons and are handled in the same way
* see MenuDemo

7. ComboBox Menu Items You can use a ComboBox as a menu item
Use the designer to add a set of Items to the combo box
You can then select a value
The click event is raised only when you click on the selected value, not when you change the selection
If you have nothing selected, the selected item will be null

8. TreeView Presents a hierarchical tree view of the data Nodes can be
Selected
Expanded and collapsed
Text of nodes can be edited
Nodes can be added or deleted programmatically

9. TreeNode All nodes in the tree are instances of TreeNode Constructors
TreeNode(string displayText)
Properties
Nodes – get TreeNodeCollection of all children of this node

10. TreeNode Methods Text – the displayed text
Checked – true if the node is checked
FullPath – the labels of all nodes from the root to this node separated by “\\”
NextNode – returns next sibling
PrevNode – returns previous sibling
Methods
Collapse – collapses the node

11. TreeNode Expand – expands the node
ExpandAll – expands all children of this node
GetNodeCount – returns the number of child nodes

12. TreeView This is the actual control Properties
Nodes – get TreeNodeCollection of all children of this node
CheckBoxes – if true, displays checkboxes beside tree nodes
SelectedNode – the selected node
LabelEdit – if true, node text can be edited

13. TreeView Events AfterSelect – after a node is selected
AfterExpanded – after a node is expanded
AfterCollapsed – after a node is collapsed
AfterEdited – after a node is edited

14. Populating a TreeView Usually, create a root TreeNode
Add the root node onto the Nodes collection of the TreeView
Create a child TreeNode and add it to the Nodes collection of the root node
Continue this way to build whole tree

15. Populating a TreeView TreeView tv = new TreeView();
TreeNode root = new TreeNode(root);
tv.Nodes.Add(root);
root.Nodes.Add(new TreeNode(“Vegetables”));
root.Nodes.Add(new TreeNode(“Fruit”));
root.Nodes.Add(new TreeNode(“Meat”));
root.Nodes.Add(new TreeNode(“Poultry”));
* see TreeDemo

16. TreeViewEventArg The signature for an event handler is
void EventHandler(object sender, EventArgs e)
TreeView events use a subclass called TreeViewEventArg
Properties
Node – the node where the event originated
You will have to use the Node member to find which tree node is affected by some events

17. TabControl Displays a series of tabs
Each tab is a different page with its own controls on it
Each tab is like a group box or panel
Create
In Visual Studio
Drop controls into the tab pages
Set the text property of every page to change the label
Right click on a tab and select “Add Tab” to add a new tab

18. TabControl Multiline – if true tabs can be in several lines
SelectedIndex – index of selected tab
SelectedTab – the selected tab
TabPages – collection of TabPages
SelectedIndexChanged – event raised when a different tab is selected
* see TabDemo

19. Automatic Layout
All of the forms we have seen so far have been laid out based on X-Y coordinates
If the outer form is resized, the contents stay at the same size and position
There are three ways to change this
The Dock property
The FlowLayoutPanel
The TableLayoutPanel

20. The Dock Property
Every control has a Dock property which can be set to
None – no docking
Left – docked to left side of container
Right – docked to right side of container
Top – docked to top of container
Bottom – docked to bottom of container
Fill – fills all available space

21. The Dock Property
When controls are docked to the sides of their containing form, resizing the form resizes the controls inside as well
* see DockDemo

22. FlowLayoutPanel Arranges its contents into horizontal or vertical rows
As form is resized, controls are arranged into new rows or columns
Created in designer by dropping controls into it
In designer it has small arrow on the top that activates menu of editing actions

23. FlowLayoutPanel FlowDirection – layout direction
BottomUp
TopDown
LeftToRight
RightToLeft
WrapContents – whether the contents should be wrapped to a new row or column or clipped
* see LayoutDemo

24. TableLayoutPanel Arranges the controls within it into rows and columns
Automatically resizes contents when the surrounding form is resized
The pull-out menu in designer can be used to add or delete rows and columns

25. TableLayoutPanel ColumnCount – get/set number of columns
RowCount – get/set number of rows
* see LayoutDemo

26. MessageBox A pop-up dialog which displays a message
Use the static Show methods to see one
DialogResult Show(string) – box with simple string and OK button
DialogResult Show(string text, string caption)
DialogResult Show(string text, string caption, MessageBoxButtons) OK
OKCancel
RetryCancel
YesNo
YesNoCancel

27. DialogResult
Abort
Cancel
Ignore No
None OK
Retry
Yes

28. Drawing So far, we have used controls to draw everything on the screen
There is a lower-level interface which can be used to draw anything into a form
Using this we can
Handle any type of event
Draw anything
Create our own controls

29. Coordinates
(0,0) X
All windows have their own coordinate space with the origin in the top-left corner
X values increase to the right
Y values increase downward
Coordinates are usually expressed as an integer number of pixels Y

30. Measurement Units Pixel is the default unit but others can be used
Graphics has a property PageUnit which is a member of the enum GraphicsUnit
Display – device units: pixels for monitors & 1/100 inch for printers
Document – 1/300 inch
Inch – inch
Millimeter – millimeter
Pixel – (default) pixel
Point – 1/72 inch
World – world coordinates

31. Drawing We have already see the Color and Font classes
To draw we are also interested in
Pen – the width & color of a line
Brush – the fill for a figure like a rectangle
SolidBrush – a solid color
TextureBrush – a pattern
Graphics – a class containing drawing methods

32. Pen A drawing object used to specify the color and width of a line
Constructor
Pen(Color, int width)
Pen(Brush, int width)
Properties
DashStyle – for dashed lines, one of
Solid
Dash
DashDot
DashDotDot
Dot

33. SolidBrush A color used to fill the interior of a closed figure
Constructor
SolidBrush(Color)
Properties
Color – get/set the brush color

34. Graphics
The graphics object is associated with a drawing surface and provides methods to draw on that surface
The graphics object is given to you by the framework, you do not create it

35. Graphics Clear(Color) – clears the entire surface with the color
DrawArc(Pen, int x, int y, int ht, int wd, int startAngle, int endAngle) – draw an arc of an ellipse contained by the rectangle
DrawEllipse(Pen, int x, int y, int ht, int wd) – draw an ellipse within the rectangle

36. Graphics DrawLine(Pen, Point, Point) – draw a line between two points
DrawPie(Pen, int x, int y, int ht, int wd) – draw an pie slice within the rectangle
DrawRectangle(Pen, int x, int y, int ht, int wd) – draw a rectangle

37. Graphics
DrawString(string, Font, Brush, single x, single y) – draw a string at the point
FillMethods
Most of the draw methods have equivalent Fill methods
The Fill methods draw a solid figure rather than an outline
They use a brush rather than a pen

38. Event Handling When you create your own control which draws you can
Add event handlers as we have done in the past
Override the methods for handling these events in the parent class
Often, it is easier to override the methods in the parent class to make behaviour inheritable

39. Event Handling Methods
void OnMouseDown(MouseEventArgs e)
void OnMouseUp(MouseEventArgs e)
void OnMouseMove(MouseEventArgs e)
void OnMouseWheel(MouseEventArgs e)
void OnKeyDown(KeyEventArgs e)
OnKeyUp(KeyEventArgs e)
void OnResize(EventArgs e)

40. MouseEventArgs Button – get button pressed
Clicks – get the number of times the button was pushed and released
Delta – number of positions mouse wheel rotated
X – mouse coordinate
Y – mouse coordinate

41. Painting Forms are painted by calling OnPaint(Graphics g)
You override this method to paint whatever you need
You NEVER call this method
You call Invalidate() when you want to be repainted and the windowing system calls OnPaint() for you

42. Overriding Methods
When you override a method, your method is called, not the one in the parent class
However, the one in the parent class often does something important
Therefore, always call the method in the base class before doing your own thing
* see WinDraw