Chapter 13. Graphical User Interface Concepts: Part 1

1. Chapter 13. Graphical User Interface Concepts: Part 1

2. Simple Windows Application • In Visual Studio 2005, if you choose • File->New Project • Windows Application • The following will be generated for you • Form1.cs • Form1.Designer.cs • Program.cs • Lets look at them

4. Program.cs using System; using System.Collections.Generic; using System.Windows.Forms; namespace SimpleApplication { static class Program { ///<summary> /// The main entry point for the application. ///</summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } } What is this?

5. Form1.cs using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace SimpleApplication { public partial class Form1 : Form { public Form1() { InitializeComponent(); } } }

6. Form1.Designer.cs namespace SimpleApplication { partial class Form1 { ///<summary> /// Required designer variable. ///</summary> private System.ComponentModel.IContainer components = null; ///<summary> /// Clean up any resources being used. ///</summary> ///<param name="disposing">true if managed resources should be disposed; otherwise, false.</param> protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code ///<summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. ///</summary> private void InitializeComponent() { this.components = new System.ComponentModel.Container(); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.Text = "Form1"; } #endregion } }

7. Application Class • The System.Windows.Forms.Application class wraps the basic functionality to start a .NET application. • This class has methods to start and stop applications and their threads, and to process Windows Messages: • DoEvents() • Exit() • ExitThread() • Run() • The class also has events and properties to synchronize execution.

8. Application Class • Run static method begins running a standard application message loop on the current thread. • Below is the overload list:

9. Partial Class • A partial class, or partial type, is a feature of C# programming languages in which the declaration of a class or a struct or an interface may be split across multiple source-code files. • Purpose • Very large classes • Separation of concerns • Multiple developer

10. Windows Forms • Forms are contained within a namespace called System.Windows.Forms that contains around 200 classes, 100 enumeration, more than 40 delegates, 7 interfaces, and 4 structures. • The inheritance lineage is Object -> MarshallByRefObject -> Component-> Control-> ScrollableControl-> Form

11. Windows Forms

12. Form • Form class represents window, provides appropriate services • properties: Size, Location, Controls, ShowInTaskbar • methods: Show, Close, SetDesktopLocation • events: Load, Click, Closing • Common to derive from Form to create custom form define custom form class MyForm : Form { public MyForm() { this.ShowInTaskbar = false; this.Location = new Point(10, 10); this.Size = new Size(100, 100); } } set properties

13. Form border • Forms can look like windows, dialogs, or tools • controlled using FormBorderStyle property • set ShowInTaskbar property to false for tool windows • window border styles show the icon from the Icon property

14. Form properties • Form has many properties • used to customize appearance and behavior public class Form : ContainerControl { public IButtonControl AcceptButton { get; set; } public IButtonControl CancelButton { get; set; } public bool HelpButton { get; set; } public Icon Icon { get; set; } public String Text { get; set; } public Size MaximumSize { get; set; } public Size MinimumSize { get; set; } public MainMenu Menu { get; set; } public bool ShowInTaskbar { get; set; } public FormBorderStyle FormBorderStyle { get; set; } ... } properties

15. SimpleForm.cs using System; using System.Windows.Forms; class SimpleForm { static void Main() { Form f1 = new Form(); f1.Text = "My Simple Form"; Application.Run(f1); } } csc /t:winexe SimpleForm.cs

16. SimpleForm2.cs using System; using System.Windows.Forms; class SimpleForm { static void Main() { Form f1 = new Form(); f1.Text = "My Simple Form2"; f1.Show(); } } What is the output?

17. SimpleForm3.cs using System.Threading; using System.Windows.Forms; class SimpleForm { static void Main() { Form f1 = new Form(); f1.Text = "My Simple Form3"; f1.Show(); f1.Text = "Time to sleep"; //Let the process go to sleep for 1000 ms (pause) Thread.Sleep(3000); f1.Text = "Time to wake up !"; //Let the process go to sleep for 1000 ms (pause) Thread.Sleep(1000); } } What is the output?

18. SimpleForm4.cs using System.Threading; using System.Windows.Forms; class SimpleForm { public static void Main() { Form f1 = new Form(); f1.Text = "What is wrong with this?"; f1.Visible = true; Thread.Sleep(3000); f1.Visible = false; Thread.Sleep(3000); f1.Text = "Coming back to live"; f1.Visible = true; Thread.Sleep(3000); Application.Run(); f1.Text = "After Application.Run is called"; } } What is the output?

19. SimpleForm5.cs using System.Threading; using System.Windows.Forms; class SimpleForm { public static void Main() { Form f1 = new Form(); f1.Text = "What is wrong with this?"; f1.Visible = true; Thread.Sleep(3000); f1.Visible = false; Thread.Sleep(3000); f1.Text = "Coming back to live"; f1.Visible = true; Thread.Sleep(3000); Application.Run(f1); Thread.Sleep(3000); f1.Text = "After Application.Run is called"; } } What is the output?

20. SimpleForm6.cs using System.Threading; using System.Windows.Forms; class SimpleForm { public static void Main() { Form f1 = new Form(); f1.Text = "How are you all doing?"; f1.Visible = true; Thread.Sleep(3000); f1.Text = "And How is your Baba?"; Application.Run(f1); Thread.Sleep(3000); f1.Text = "After Application.Run is called"; MessageBox.Show("And your Daddy too?"); } } What is the output?

21. Conclusion • Main creates the form and displays it. • The form is given to Application.Run where it continues to exist. • The form takes control of execution until the form is dismissed. • When the form is dismissed, presumably, the Application.Run method continues (err, ends). • The Application.Run method returns control to Main, which then calls the MessageBox.Show method. • The application ends after the MessageBox is dismissed

22. SimpleForm7.cs using System.Threading; using System.Windows.Forms; class SimpleForm { public static void Main() { Form f0 = new Form(); f0.Text = "How are you?"; Form f1 = new Form(); f1.Text = "How is C#?"; Form f2 = new Form(); f2.Text = "How is C++"; f0.Show(); f2.Show(); Application.Run(f1); MessageBox.Show("Where are we?"); f2.Text = "F2, after Application.Run is called"; Thread.Sleep(3000); } } Take Home Bring back your description Quiz

23. Not Very Simple Windows Application! • Drag and drop textbox and button from the toolbox into the Form • Lets see what happened to our three files. • Program.cs Form1.cs Form1.Designer.cs

24. Program.cs using System; using System.Collections.Generic; using System.Windows.Forms; namespace SimpleApplication { static class Program { ///<summary> /// The main entry point for the application. ///</summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } } NO CHANGES!

25. Form1.cs using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace SimpleApplication { public partial class Form1 : Form { public Form1() { InitializeComponent(); } } } NO CHANGES!

26. Form1.Designer.cs We have two new fields namespace SimpleApplication { partial class Form1 { //SAME AS BEFORE CODE OMMITED FOR SPACE private System.Windows.Forms.TextBox textBox1; private System.Windows.Forms.Button button1; private void InitializeComponent() { this.textBox1 = new System.Windows.Forms.TextBox(); this.button1 = new System.Windows.Forms.Button(); this.SuspendLayout(); // textBox1 this.textBox1.Location = new System.Drawing.Point(72, 24); this.textBox1.Name = "textBox1"; this.textBox1.Size = new System.Drawing.Size(100, 20); this.textBox1.TabIndex = 0; // button1 this.button1.Location = new System.Drawing.Point(82, 59); this.button1.Name = "button1"; this.button1.Size = new System.Drawing.Size(75, 23); this.button1.TabIndex = 1; this.button1.Text = "button1"; this.button1.UseVisualStyleBackColor = true; // Form1 this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(246, 109); this.Controls.Add(this.button1); this.Controls.Add(this.textBox1); this.Name = "Form1"; this.Text = "Form1"; this.ResumeLayout(false); this.PerformLayout();} #endregion } } The fields properties are initialized The fields are attached to the Form

27. Not Simple Windows Application! • Lets say I want to find the square of the number entered • Double click on the button, and suddenly Form1.cs is opened for me and the following code is displayed for me.

28. Form1.cs using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace SimpleApplication { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { int x = int.Parse(textBox1.Text); x = x*x; MessageBox.Show(x.ToString()); } } } This method is written for me I wrote this code

29. Form1.Designer.cs namespace SimpleApplication { partial class Form1 { //SAME AS BEFORE CODE OMMITED FOR SPACE //THE BUTTON1 IS THE PART THAT CHANGES // button1 // this.button1.Location = new System.Drawing.Point(82, 59); this.button1.Name = "button1"; this.button1.Size = new System.Drawing.Size(75, 23); this.button1.TabIndex = 1; this.button1.Text = "button1"; this.button1.UseVisualStyleBackColor = true; this.button1.Click += new System.EventHandler(this.button1_Click); } } control Event Event handler (method name)

30. Form as container • Form manages a list of controls • stored in Controls collection property all forms inherit Controls collection class MyForm : Form { Button button1 = new Button(); Label label1 = new Label (); public MyForm() { ... this.Controls.Add(button1); this.Controls.Add(label1 ); } ... } add to collection myForm button1 label1 Controls

31. What We Just Did? • We have attached an event handler for the click event. • Button has Click event • If this event happens (some one clicks on the button) • button1_Click method will be executed.

32. SimpleForm8.csI like this code.. using System; using System.Threading; using System.Windows.Forms; class SimpleForm { public static void Main() { MyForm f1 = new MyForm(); Application.Run(f1); } } class MyForm : Form { private TextBox textBox1; private Button button1; public MyForm() { this.textBox1 = new System.Windows.Forms.TextBox(); this.button1 = new System.Windows.Forms.Button(); this.textBox1.Location = new System.Drawing.Point(72, 24); this.textBox1.Name = "textBox1"; this.button1.Location = new System.Drawing.Point(82, 59); this.button1.Name = "button1"; this.button1.Text = "button1"; this.button1.Click += new System.EventHandler(this.button1_Click); this.Controls.Add(this.button1); this.Controls.Add(this.textBox1); this.Name = "Form1"; this.Text = "Form1"; } private void button1_Click(object sender, EventArgs e) { int x = int.Parse(textBox1.Text); x = x * x; MessageBox.Show(x.ToString()); } }