Overview Describe the structure of a Windows Forms application Introduce deployment over networks

Transcription

1 Windows Forms

2 Overview Describe the structure of a Windows Forms application application entry point forms components and controls Introduce deployment over networks 2

3 Windows Forms Windows Forms are classes for building UIs forms, controls, dialogs, etc. part of the.net Framework Library core classes in System.Windows.Forms namespace Possible uses include: stand-alone Windows applications web services front-ends intranet smart clients 3

4 Visual Studio Visual Studio.NET provides development environment starter templates, drag-and-drop editing, property grid, etc. 4

5 Application Structure Windows Forms application has three main pieces the application itself forms in the application controls and components on the forms Application mainform myform label1 button1 Label "Hello, World!" Button "OK" 5

6 Application Application class represents the application itself Run method processes UI events delivered by Windows provides access to application environment ExecutablePath, CommonAppDataPath, UserAppDataPath, etc. no instances, all members are static class MyApp public static void Main() MyForm form = new MyForm(); start application Application.Run(form); 6

7 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 set properties class MyForm : Form public MyForm() this.showintaskbar = false; this.location = new Point(10, 10); this.size = new Size(100, 100); 7

8 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 8

9 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; properties 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;... 9

10 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 (); add to collection public MyForm()... this.controls.add(button1); this.controls.add(label1 );... myform Controls button1 label1 10

11 Form layout Form determines layout for controls it manages recalculates as needed, such as when user resizes form tries to accommodate control preferences for size and location uses Anchor and Dock property of each control can override OnLayout method to do custom layout resize 11

12 Controls Controls are visual components derived from Control class common controls supplied Object Component Control ButtonBase Button CheckBox RadioButton ListControl ComboBox ListBox DataGrid DateTimePicker GroupBox Label MonthCalendar PictureBox ProgressBar Splitter StatusBar ScrollableControl ContainerControl Form PropertyGrid UserControl Panel TabPage 12

13 Control properties Controls supply many properties used to customize appearance and behavior public class MyForm : Form private Button button1; public MyForm() button1 = new Button(); set properties button1.name = "OK button"; button1.text = "OK";... 13

14 Control events Controls offer events click mouse or keyboard activity property value change paint etc. events public class Control : Component... public event EventHandler Click; public event EventHandler Enter; public event EventHandler TextChanged; public event KeyPressEventHandler KeyPress; public event MouseEventHandler MouseDown; public event PaintEventHandler Paint;... 14

15 Event handlers Several types of event handler delegates generic EventHandler used for many events specific types for some events such as mouse and keyboard Event handlers have 2 arguments control that generated event event details in EventArgs or derived object delegate void EventHandler (object sender, EventArgs e); delegate void MouseEventHandler (object sender, MouseEventArgs e); delegate void KeyPressEventHandler(object sender, KeyPressEventArgs e); the control that generated the event event details 15

16 EventArgs Event handlers pass event details to handler passed in EventArgs or derived class object generic base class so no event data info specific to mouse event info specific to keyboard event public class EventArgs class MouseEventArgs : EventArgs public MouseButtons Button get; public int Clicks get; public int X get; public int Y get;... class KeyPressEventArgs : EventArgs public char KeyChar get;... 16

17 Event registration Clients can register for events define method with signature required by delegate create delegate instance and add to event public class MyForm : Form private Button button1; define method register void button1_click(object sender, EventArgs args)... public MyForm()... button1.click += new EventHandler(this.button1_Click);... 17

18 Components Components are non-visual elements useful in UI e.g. Timer, FileSystemWatcher, EventLog, etc. extend System.ComponentModel.Component components in toolbox shown in component tray when added to form 18

19 Threading Control should only be accessed by the creating thread messages from different threads subject to interleaving resulting race conditions can lead to inconsistent behavior Control class provides methods for thread-switching see docs for InvokeRequired, Invoke, BeginInvoke dequeue window message queue owning thread window controls access Login Name: Password: access other thread OK Cancel 19

20 No-touch deployment Windows forms applications can be deployed automatically client uses browser to access executable needed assemblies downloaded and stored in download cache program runs locally executable downloaded only if changed since last run Client GET /App.exe HTTP/1.1 Server cache App.exe App.exe 20

21 Summary Windows Forms supports UI development applications, forms, controls integration with designer no-touch deployment over networks 21