The ListBox Class Common Controls and Components
5.1.9 The ListBox Class
The ListBox class represents a box that contains a list of items. The following are its more important properties: MultiColumn This is a Boolean that indicates whether the listbox has more than one column. Its default value is False . ColumnWidth In a multicolumn listbox, this property represents the width of each column in pixels. By default, the value of this property is zero, which makes each column have a default width. Items This is the most important property of the ListBox class. It returns the ListBox.ObjectCollection class, which is basically the Items collection in the ListBox. You can programmatically add an item using the Add method or add a range of items using the AddRange method of the ListBox.ObjectCollection class. For example, the following code adds the names of vegetables and fruits to a ListBox object named listBox1: listBox1.Items.AddRangeNew Object _ {apple, avocado, banana, carrot, _ mandarin, orange} For more information about the ListBox.ObjectCollection class, see Sect ion 5.1.10 . SelectionMode This property determines whether multi-item selection is possible in a ListBox object. It can be assigned any member of the SelectionMode enumeration: None , One the default value, MultiSimple , and MultiExtended . Both MultiSimple and MultiExtended allow the user to select more than one item. However, MultiExtended allows the use of the Shift, Ctrl, and arrow keys to make a selection. SelectedIndex This is the index of the selected item. The index is zero-based. If more than one item is selected, this property represents the lowest index. If no item is selected, the property returns -1. 193 SelectedIndices This read-only property returns the indices to all items selected in a ListBox object in the form of a ListBox.SelectedIndexCollection object. The ListBox.SelectedIndexCollection class has a Count property that returns the number of selected indices and an Item property that returns the index number. For example, the following code returns the index number of all selected items in a ListBox control named listBox1: Dim selectedIndices As ListBox.SelectedIndexCollection Obtain the selected indices. selectedIndices = listBox1.SelectedIndices Get the number of indices. Dim count As Integer = selectedIndices.Count Dim i As Integer For i = 0 To count - 1 Console.WriteLineselectedIndicesi Next SelectedItem This read-only property returns the selected item as an object of type Object. You must cast the returned value to an appropriate type, which is normally String. If more than one item is selected, the property returns the item with the lowest index. SelectedItems This read-only property returns all items selected in a ListBox object in the form of a ListBox.SelectedObjectCollection object. The ListBox.SelectedObjectCollection class has a Count property that returns the number of items in the collection and an Item property that you can use to obtain the selected item. For example, the following code displays all the selected items of a ListBox control called listBox1: Dim selectedItems As ListBox.SelectedObjectCollection selectedItems = listBox1.SelectedItems Dim count As Integer = selectedItems.Count Dim i As Integer For i = 0 To count - 1 Console.WriteLineselectedItemsi Next Sorted A value of True means that the items are sorted. Otherwise, the items are not sorted. By default, the value of this property is False . Text This is the currently selected items text. TopIndex This is the index of the first visible item in the ListBox. The value changes as the user scrolls through the items.5.1.10 The ListBox.ObjectCollection Class
Parts
» VB.NET - (O'Reilly) Programming Visual Basic NET
» What Is the Microsoft .NET Framework?
» hello, world An Example Visual Basic .NET Program
» Hello, Windows An Example Visual Basic .NET Program
» Hello, Browser An Example Visual Basic .NET Program
» Source Files Identifiers The Visual Basic .NET Language
» Numeric Literals String Literals Character Literals
» Date Literals Boolean Literals Nothing Summary of Literal Formats
» Custom Types Collections Types
» The Namespace Statement The Imports Statement
» Symbolic Constants Scope The Visual Basic .NET Language
» Access Modifiers Assignment The Visual Basic .NET Language
» Unary Operators Arithmetic Operators
» Relational Operators Operators and Expressions
» String-Concatenation Operators Bitwise Operators
» Logical Operators Operator Precedence
» Call Exit Branching Statements
» Goto If RaiseEvent Branching Statements
» Return Select Case Branching Statements
» For Each Iteration Statements
» Object Instantiation and New Constructors
» Handling Events Inheritance Classes
» Passing arrays as parameters
» Variable-length parameter lists Main method
» Implementing interface methods Overriding inherited methods
» Overloading Overloading inherited methods
» The MyBase Keyword Nested Classes Destructors
» Interfaces The Visual Basic .NET Language
» Enumerations The Visual Basic .NET Language
» Exceptions The Visual Basic .NET Language
» Delegates The Visual Basic .NET Language
» Using Events and Delegates Together
» Creating Custom Attributes Attributes
» Standard Modules Conditional Compilation
» Summary The Visual Basic .NET Language
» Common Language Infrastructure CLI and Common Language Runtime CLR
» Global Assembly Cache GAC Comparison of Assemblies, Modules, and Namespaces
» Application Domains Common Language Specification CLS
» Intermediate Language IL and Just-In-Time JIT Compilation Metadata
» Finalize Memory Management and Garbage Collection
» Dispose Memory Management and Garbage Collection
» A Brief Tour of the .NET Framework Namespaces
» Configuration File Format Configuration
» Configuration Section Groups The appSettings Section
» Adding event handlers Creating a Form in Code
» Handling Form Events Windows Forms I: Developing Desktop Applications
» Relationships Between Forms Windows Forms I: Developing Desktop Applications
» Merging Menus MDI Applications
» Detecting MDI Child Window Activation
» Component Attributes Windows Forms I: Developing Desktop Applications
» The Graphics Class 2-D Graphics Programming with GDI+
» The Pen Class 2-D Graphics Programming with GDI+
» The Brush Class 2-D Graphics Programming with GDI+
» System colors The Color Structure
» Alpha Blending 2-D Graphics Programming with GDI+
» Antialiasing 2-D Graphics Programming with GDI+
» The PrintPageEventArgs Class Printing
» The OnBeginPrint and OnEndPrint Methods Choosing a Printer
» The PageSettings Class Printing
» The PrinterSettings Class Printing
» Page Setup Dialog Box Print Preview
» Summary Windows Forms I: Developing Desktop Applications
» The Button Class The CheckBox Class The ComboBox Class
» The DateTimePicker Class The GroupBox Class The ImageList Class
» The Label Class The LinkLabel Class
» The ListBox Class Common Controls and Components
» The ListBox.ObjectCollection Class
» The ListView Class Common Controls and Components
» The MonthCalendar Class Common Controls and Components
» The Panel Class The PictureBox Class
» The RadioButton Class Common Controls and Components
» The TextBox Class The Timer Class
» Other Controls and Components
» Control Events Windows Forms II: Controls, Common Dialog Boxes, and Menus
» The Anchor Property Form and Control Layout
» Controlling dock order The Dock Property
» The Splitter control The Dock Property
» ColorDialog FontDialog OpenFileDialog Common Dialog Boxes
» PageSetupDialog PrintDialog PrintPreviewDialog SaveFileDialog
» Adding Menus in the Visual Studio .NET Windows Forms Designer
» Programmatically Creating Menus Menus
» Building Controls from Other Controls
» Building Controls That Draw Themselves Building Nonrectangular Controls
» Summary Windows Forms II: Controls, Common Dialog Boxes, and Menus
» Setting control properties using attributes Adding event handlers
» AutoEventWireup Handling Page Events
» The Button control Web Controls
» The CheckBox control The DropDownList control
» The Image control The Label control
» The ListBox control Web Controls
» The RadioButton control Web Controls
» The Table control Web Controls
» The TextBox control Web Controls
» Other web controls Web Controls
» HTML Controls Handling Control Events
» Programmatically Instantiating Controls More About Server Controls
» More About Validation-Control Tag Attributes
» Using Validation-Control Properties Providing a Summary View of Validation Failures
» Performing Custom Validation Adding Validation
» Using Directives to Modify Web Page Compilation
» The Server Object ASP.NET Objects: Interacting with the Framework
» The Application Object The Session Object The Cache Object The Request Object
» The Response Object ASP.NET Objects: Interacting with the Framework
» Discovering Browser Capabilities ASP.NET and Web Forms: Developing Browser-Based Applications
» The Session Object Maintaining State
» The Application Object Maintaining State
» Session and Application Startup and Shutdown global.asax Compiles to a Class
» Adding Global Objects Application-Level Code and global.asax
» ASP.NET authorization Authorization
» Windows NTFS authorization Code-access authorization
» IUSR_ComputerName Impersonation Accessing Network Resources
» User Controls Designing Custom Controls
» Creating a custom server control using Visual Studio .NET
» Creating a custom server control in code Using a custom server control in Visual Studio .NET
» Summary ASP.NET and Web Forms: Developing Browser-Based Applications
» The WebService Attribute The WebMethod Attribute
» Testing a Web Service with a Browser
» Consuming a Web Service in Visual Studio .NET
» Consuming a Web Service in Notepad
» Synchronous Versus Asynchronous Calls
» Web-Service Descriptions Web-Service Discovery
» Limitations of Web Services Summary
» A Brief History of Universal Data Access Managed Providers
» Connecting to a SQL Server Database
» Connecting to an OLE DB Data Source
» The DataSet Class Finding Tables
» Finding Column Values Finding Column Definitions Changing, Adding, and Deleting Rows
» Writing Updates Back to the Data Source
» Relations Between DataTables in a DataSet
» The DataSets XML Capabilities
» Binding a DataSet to a Windows Forms DataGrid
» Binding a DataSet to a Web Forms DataGrid
» Typed DataSets ADO.NET: Developing Database Applications
» Reading Data Using a DataReader
Show more