05 - WinForms.md

Windows Forms – Introduction, Menus, Events

• 1. Application Class
• 2. Form Class and Control Class
  • 2.1. Partial Classes
  • 2.2. Properties
• 3. Menus
• 4. Mouse and Keyboard Events
  • 4.1. Mouse Events
  • 4.2. Keyboard Events

1. Application Class

Assignment

1. Create a new project with the name “MouseEvents”
2. Change the name of the default form to “MainForm”

2. Form Class and Control Class

2.1. Partial Classes

It is possible to split the definition of a class or a struct, an interface or a method over two or more source files. Each source file contains a section of the type or method definition, and all parts are combined when the application is compiled.

Assignment

1. Open the “*.Designer.cs” file associated to the form

2.2. Properties

Frequently used properties:

• Design: Name, etc.
• Appearence: Text, ForeColor, BackColor, Font, etc.

3. Menus

Assignment

Sample Code available – Check the “SimpleWebBrowser” Sample

1. Create the following application
   

2. Create a setup file for the application, that can be redistributed to other users

   You need to right click on the project in the “Solution Explorer” window and choose the publish option

4. Mouse and Keyboard Events

4.1. Mouse Events

Event	Event argument	Description
Click	EventArgs	Raised when the control is clicked.
DoubleClick	EventArgs	Raised when the control is double-clicked.
MouseEnter	EventArgs	Raised when the mouse cursor enters the control.
MouseHover	EventArgs	Raised when the mouse cursor hovers over the control.
MouseLeave	EventArgs	Raised when the mouse cursor leaves the control.
MouseDown	MouseEventArgs	Raised when the mouse cursor is over the control and a mouse button is pressed.
MouseMove	MouseEventArgs	Raised when the mouse cursor is moved over the control.
MouseWheel	MouseEventArgs	Raised when the control has focus and the mouse wheel is rotated.
MouseUp	MouseEventArgs	Raised when the mouse cursor is over the control and a mouse button is released.

Click events are logically higher-level events of a control. They are often raised by other actions, such as pressing the ENTER key when the control has focus.

Depressing a mouse button when the cursor is over a control typically raises the following series of events from the control:

• MouseDown event
• Click event
• MouseClick event
• MouseUp event

Assignment

Sample code available – Check the “MouseEvents” Sample

1. Create the following UI
   

2. Add the following code

   public partial class MainForm : Form
   {
   	public MainForm()
   	{
   		InitializeComponent();
   	}
   
   	private void btnReset_Click(object sender, EventArgs e)
   	{
   		lbl.Text = "";
   		txt.Text = "";
   	}
   
   	//similar: lbl_MouseHover, lbl_MouseLeave, lbl_Click, lbl_DoubleClick
   	private void lbl_MouseEnter(object sender, EventArgs e)
   	{
   		lbl.Text = "MouseEnter";
   		TextBoxDraw("###Label MouseEnter");
   	}
   
   	//similar: lbl_MouseMove, lbl_MouseUp, lbl_MouseWheel
   	private void lbl_MouseDown(object sender, MouseEventArgs e)
   	{
   		lbl.Text = "MouseDown";
   		var str = "###Label MouseDown";
   		str += Environment.NewLine + "Button:  " + e.Button;
   		str += Environment.NewLine + "Clicks:  " + e.Clicks;
   		str += Environment.NewLine + "Delta:  " + e.Delta;
   		str += Environment.NewLine + "X:  " + e.X;
   		str += Environment.NewLine + "Y:  " + e.Y;
   		TextBoxDraw(str);
   	}
   
   	//similar: OnMouseHover, OnMouseLeave
   	protected override void OnMouseEnter(EventArgs e)
   	{
   		base.OnMouseEnter(e);
   		TextBoxDraw("###Form MouseEnter");
   	}
   
   	private void TextBoxDraw(string str)
   	{
   		txt.AppendText(Environment.NewLine + str);
   	}
   }

4.2. Keyboard Events

Event	Event argument	Description
KeyDown	KeyEventArgs	Raised when a key is pressed. The KeyDown event occurs prior to the KeyPress event.
KeyPress	KeyPressEventArgs	Raised when a character generating key is pressed. The KeyPress event occurs after the KeyDown event and before the KeyUp event.
KeyUp	KeyEventArgs	Raised when a key is released.

Assignment

We want to create a numeric only TextBox that can be used to build a simple calculator application, such as the one below.

Sample code available – Check the “KeyEvents” Sample

1. Create a new project with the name “KeyEventsNumericTextBox”

2. Add a TextBox and name it “tbNumericTextBox”

3. Add the following event handler at the end of this document

4. Change the previous event handler in order to allow the use of the “BackSpace” key

5. Change the previous event handler in order to allow the digit separator for the current culture

   private void tbNumericTextBox_KeyPress(object sender, KeyPressEventArgs e)
   {
   	OnKeyPress(e);
   
   	if (!char.IsDigit(e.KeyChar))
   	{
   		// Consume this invalid key
   		e.Handled = true;
   	}
   }