ListControl Class

Definition

Serves as the abstract base class that defines the properties, methods, and events common for all list-type controls.

public ref class ListControl abstract : System::Web::UI::WebControls::DataBoundControl, System::Web::UI::IEditableTextControl
[System.Web.UI.ControlValueProperty("SelectedValue")]
public abstract class ListControl : System.Web.UI.WebControls.DataBoundControl, System.Web.UI.IEditableTextControl
type ListControl = class
    inherit DataBoundControl
    interface IEditableTextControl
    interface ITextControl
Public MustInherit Class ListControl
Inherits DataBoundControl
Implements IEditableTextControl
Inheritance
ListControl
Derived
Attributes
Implements

Examples

The following code example demonstrates how to select items in a ListBox control. If the item is found in the text box, the item is selected and a message is displayed stating the name of the selected item. If the item is not found, no item is selected and a message is displayed stating that the item was not found.

Important

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.


<%@ Page Language="C#" AutoEventWireup="True" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" > 

<head runat="server">
    <title> ListControl SelectedValue Example </title>
<script runat="server">

      void Button_Click(Object sender, EventArgs e)
      {

         // Perform this operation in a try-catch block in case the item is not found.
         try
         {
            List.SelectedValue = ItemTextBox.Text;
            MessageLabel.Text = "You selected " + List.SelectedValue + ".";
         }
         catch (Exception ex)
         {
            List.SelectedValue = null;
            MessageLabel.Text = "Item not found in ListBox control.";
         }
             
      }

   </script>

</head>

<body>

   <form id="form1" runat="server">

      <h3> ListControl SelectedValue Example </h3>
 
      <asp:ListBox ID="List"
           runat="server">

         <asp:ListItem>Item 1</asp:ListItem>
         <asp:ListItem>Item 2</asp:ListItem>
         <asp:ListItem>Item 3</asp:ListItem>
         <asp:ListItem>Item 4</asp:ListItem>

      </asp:ListBox>

      <hr />

      Enter the value of the item to select: <br />
      <asp:TextBox ID="ItemTextBox"
           MaxLength="6"
           Text="Item 1"
           runat="server"/>

      &nbsp;&nbsp;

      <asp:Button ID="SelectButton"
           Text="Select Item"
           OnClick="Button_Click"
           runat="server"/>

      <br /><br />

      <asp:Label ID="MessageLabel"
           runat="server"/>     

   </form>

</body>
</html>

<%@ Page Language="VB" AutoEventWireup="True" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" > 

<head runat="server">
    <title> ListControl SelectedValue Example </title>
<script runat="server">

      Sub Button_Click(sender As Object, e As EventArgs)

         ' Perform this operation in a try-catch block in case the item is not found.
         Try
   
            List.SelectedValue = ItemTextBox.Text
            MessageLabel.Text = "You selected " & List.SelectedValue + "."
        
         Catch ex As Exception
     
            List.SelectedValue = Nothing         
            MessageLabel.Text = "Item not found in ListBox control."
     
         End Try
             
      End Sub

   </script>

</head>

<body>

   <form id="form1" runat="server">

      <h3> ListControl SelectedValue Example </h3>
 
      <asp:ListBox ID="List"
           runat="server">

         <asp:ListItem>Item 1</asp:ListItem>
         <asp:ListItem>Item 2</asp:ListItem>
         <asp:ListItem>Item 3</asp:ListItem>
         <asp:ListItem>Item 4</asp:ListItem>

      </asp:ListBox>

      <hr />

      Enter the value of the item to select: <br />
      <asp:TextBox ID="ItemTextBox"
           MaxLength="6"
           Text="Item 1"
           runat="server"/>

      &nbsp;&nbsp;

      <asp:Button ID="SelectButton"
           Text="Select Item"
           OnClick="Button_Click"
           runat="server"/>

      <br /><br />

      <asp:Label ID="MessageLabel"
           runat="server"/>     

   </form>

</body>
</html>

Remarks

An instance of the ListControl abstract class cannot be created directly. Instead, this class is inherited by other classes, such as the CheckBoxList, DropDownList, ListBox, and RadioButtonList classes, to provide common basic functionality.

The properties of the ListControl class allow you to specify the source of the data to populate the list control. Use the DataSource property to specify the data source to bind to the list control. If the data source contains more than one table, use the DataMember property to specify the table to use. You can bind different fields in the data source to the ListItem.Text and ListItem.Value properties of the items in the list control by setting the DataTextField and DataValueField properties, respectively. The text displayed for each item in the list control can by formatted by setting the DataTextFormatString property.

All items displayed in the list control are stored in the Items collection. You can programmatically specify or determine the index of a selected item in the list control by using the SelectedIndex property. The properties of the selected item can be accessed by using the SelectedItem property.

The ListControl class provides the SelectedIndexChanged event, which is raised when the selection in the list control changes between posts to the server. This allows you to provide a custom handler for this event. For more information about how to handle events, see Handling and Raising Events.

The ListControl class implements the IEditableTextControl interface so that derived list-type controls can be used in the template mode of other controls.

Constructors

ListControl()

Initializes a new instance of the ListControl class.

Properties

AccessKey

Gets or sets the access key that allows you to quickly navigate to the Web server control.

(Inherited from WebControl)
Adapter

Gets the browser-specific adapter for the control.

(Inherited from Control)
AppendDataBoundItems

Gets or sets a value that indicates whether list items are cleared before data binding.

AppRelativeTemplateSourceDirectory

Gets or sets the application-relative virtual directory of the Page or UserControl object that contains this control.

(Inherited from Control)
Attributes

Gets the collection of arbitrary attributes (for rendering only) that do not correspond to properties on the control.

(Inherited from WebControl)
AutoPostBack

Gets or sets a value indicating whether a postback to the server automatically occurs when the user changes the list selection.

BackColor

Gets or sets the background color of the Web server control.

(Inherited from WebControl)
BindingContainer

Gets the control that contains this control's data binding.

(Inherited from Control)
BorderColor

Gets or sets the border color of the Web control.

(Inherited from WebControl)
BorderStyle

Gets or sets the border style of the Web server control.

(Inherited from WebControl)
BorderWidth

Gets or sets the border width of the Web server control.

(Inherited from WebControl)
CausesValidation

Gets or sets a value indicating whether validation is performed when a control that is derived from the ListControl class is clicked.

ChildControlsCreated

Gets a value that indicates whether the server control's child controls have been created.

(Inherited from Control)
ClientID

Gets the control ID for HTML markup that is generated by ASP.NET.

(Inherited from Control)
ClientIDMode

Gets or sets the algorithm that is used to generate the value of the ClientID property.

(Inherited from Control)
ClientIDSeparator

Gets a character value representing the separator character used in the ClientID property.

(Inherited from Control)
Context

Gets the HttpContext object associated with the server control for the current Web request.

(Inherited from Control)
Controls

Gets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy.

(Inherited from Control)
ControlStyle

Gets the style of the Web server control. This property is used primarily by control developers.

(Inherited from WebControl)
ControlStyleCreated

Gets a value indicating whether a Style object has been created for the ControlStyle property. This property is primarily used by control developers.

(Inherited from WebControl)
CssClass

Gets or sets the Cascading Style Sheet (CSS) class rendered by the Web server control on the client.

(Inherited from WebControl)
DataItemContainer

Gets a reference to the naming container if the naming container implements IDataItemContainer.

(Inherited from Control)
DataKeysContainer

Gets a reference to the naming container if the naming container implements IDataKeysControl.

(Inherited from Control)
DataMember

Gets or sets the specific table in the DataSource to bind to the control.

DataSource

Gets or sets the data source that populates the items of the list control.

DataTextField

Gets or sets the field of the data source that provides the text content of the list items.

DataTextFormatString

Gets or sets the formatting string used to control how data bound to the list control is displayed.

DataValueField

Gets or sets the field of the data source that provides the value of each list item.

DesignMode

Gets a value indicating whether a control is being used on a design surface.

(Inherited from Control)
Enabled

Gets or sets a value indicating whether the Web server control is enabled.

(Inherited from WebControl)
EnableTheming

Gets or sets a value indicating whether themes apply to this control.

(Inherited from WebControl)
EnableViewState

Gets or sets a value indicating whether the server control persists its view state, and the view state of any child controls it contains, to the requesting client.

(Inherited from Control)
Events

Gets a list of event handler delegates for the control. This property is read-only.

(Inherited from Control)
Font

Gets the font properties associated with the Web server control.

(Inherited from WebControl)
ForeColor

Gets or sets the foreground color (typically the color of the text) of the Web server control.

(Inherited from WebControl)
HasAttributes

Gets a value indicating whether the control has attributes set.

(Inherited from WebControl)
HasChildViewState

Gets a value indicating whether the current server control's child controls have any saved view-state settings.

(Inherited from Control)
Height

Gets or sets the height of the Web server control.

(Inherited from WebControl)
ID

Gets or sets the programmatic identifier assigned to the server control.

(Inherited from Control)
IdSeparator

Gets the character used to separate control identifiers.

(Inherited from Control)
IsChildControlStateCleared

Gets a value indicating whether controls contained within this control have control state.

(Inherited from Control)
IsEnabled

Gets a value indicating whether the control is enabled.

(Inherited from WebControl)
IsTrackingViewState

Gets a value that indicates whether the server control is saving changes to its view state.

(Inherited from Control)
IsViewStateEnabled

Gets a value indicating whether view state is enabled for this control.

(Inherited from Control)
Items

Gets the collection of items in the list control.

LoadViewStateByID

Gets a value indicating whether the control participates in loading its view state by ID instead of index.

(Inherited from Control)
NamingContainer

Gets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same ID property value.

(Inherited from Control)
Page

Gets a reference to the Page instance that contains the server control.

(Inherited from Control)
Parent

Gets a reference to the server control's parent control in the page control hierarchy.

(Inherited from Control)
RenderingCompatibility

Gets a value that specifies the ASP.NET version that rendered HTML will be compatible with.

(Inherited from Control)
SelectedIndex

Gets or sets the lowest ordinal index of the selected items in the list.

SelectedItem

Gets the selected item with the lowest index in the list control.

SelectedValue

Gets the value of the selected item in the list control, or selects the item in the list control that contains the specified value.

Site

Gets information about the container that hosts the current control when rendered on a design surface.

(Inherited from Control)
SkinID

Gets or sets the skin to apply to the control.

(Inherited from WebControl)
Style

Gets a collection of text attributes that will be rendered as a style attribute on the outer tag of the Web server control.

(Inherited from WebControl)
SupportsDisabledAttribute

Gets a value that indicates whether the control should set the disabled attribute of the rendered HTML element to "disabled" when the control's IsEnabled property is false.

(Inherited from WebControl)
TabIndex

Gets or sets the tab index of the Web server control.

(Inherited from WebControl)
TagKey

Gets the HtmlTextWriterTag value for the ListControl control.

TagName

Gets the name of the control tag. This property is used primarily by control developers.

(Inherited from WebControl)
TemplateControl

Gets or sets a reference to the template that contains this control.

(Inherited from Control)
TemplateSourceDirectory

Gets the virtual directory of the Page or UserControl that contains the current server control.

(Inherited from Control)
Text

Gets or sets the SelectedValue property of the ListControl control.

ToolTip

Gets or sets the text displayed when the mouse pointer hovers over the Web server control.

(Inherited from WebControl)
UniqueID

Gets the unique, hierarchically qualified identifier for the server control.

(Inherited from Control)
ValidateRequestMode

Gets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values.

(Inherited from Control)
ValidationGroup

Gets or sets the group of controls for which the control that is derived from the ListControl class causes validation when it posts back to the server.

ViewState

Gets a dictionary of state information that allows you to save and restore the view state of a server control across multiple requests for the same page.

(Inherited from Control)
ViewStateIgnoresCase

Gets a value that indicates whether the StateBag object is case-insensitive.

(Inherited from Control)
ViewStateMode

Gets or sets the view-state mode of this control.

(Inherited from Control)
Visible

Gets or sets a value that indicates whether a server control is rendered as UI on the page.

(Inherited from Control)
Width

Gets or sets the width of the Web server control.

(Inherited from WebControl)

Methods

AddAttributesToRender(HtmlTextWriter)

Applies HTML attributes and styles to render to the specified HtmlTextWriter object.

AddedControl(Control, Int32)

Called after a child control is added to the Controls collection of the Control object.

(Inherited from Control)
AddParsedSubObject(Object)

Notifies the server control that an element, either XML or HTML, was parsed, and adds the element to the server control's ControlCollection object.

(Inherited from Control)
ApplyStyle(Style)

Copies any nonblank elements of the specified style to the Web control, overwriting any existing style elements of the control. This method is primarily used by control developers.

(Inherited from WebControl)
ApplyStyleSheetSkin(Page)

Applies the style properties defined in the page style sheet to the control.

(Inherited from Control)
BeginRenderTracing(TextWriter, Object)

Begins design-time tracing of rendering data.

(Inherited from Control)
BuildProfileTree(String, Boolean)

Gathers information about the server control and delivers it to the Trace property to be displayed when tracing is enabled for the page.

(Inherited from Control)
ClearCachedClientID()

Sets the cached ClientID value to null.

(Inherited from Control)
ClearChildControlState()

Deletes the control-state information for the server control's child controls.

(Inherited from Control)
ClearChildState()

Deletes the view-state and control-state information for all the server control's child controls.

(Inherited from Control)
ClearChildViewState()

Deletes the view-state information for all the server control's child controls.

(Inherited from Control)
ClearEffectiveClientIDMode()

Sets the ClientIDMode property of the current control instance and of any child controls to Inherit.

(Inherited from Control)
ClearSelection()

Clears out the list selection and sets the Selected property of all items to false.

CopyBaseAttributes(WebControl)

Copies the properties not encapsulated by the Style object from the specified Web server control to the Web server control that this method is called from. This method is used primarily by control developers.

(Inherited from WebControl)
CreateChildControls()

Called by the ASP.NET page framework to notify server controls that use composition-based implementation to create any child controls they contain in preparation for posting back or rendering.

(Inherited from Control)
CreateControlCollection()

Creates a new ControlCollection object to hold the child controls (both literal and server) of the server control.

(Inherited from Control)
CreateControlStyle()

Creates the style object that is used internally by the WebControl class to implement all style related properties. This method is used primarily by control developers.

(Inherited from WebControl)
DataBind()

Binds a data source to the invoked server control and all its child controls.

(Inherited from Control)
DataBind(Boolean)

Binds a data source to the invoked server control and all its child controls with an option to raise the DataBinding event.

(Inherited from Control)
DataBindChildren()

Binds a data source to the server control's child controls.

(Inherited from Control)
Dispose()

Enables a server control to perform final clean up before it is released from memory.

(Inherited from Control)
EndRenderTracing(TextWriter, Object)

Ends design-time tracing of rendering data.

(Inherited from Control)
EnsureChildControls()

Determines whether the server control contains child controls. If it does not, it creates child controls.

(Inherited from Control)
EnsureID()

Creates an identifier for controls that do not have an identifier assigned.

(Inherited from Control)
Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
FindControl(String)

Searches the current naming container for a server control with the specified id parameter.

(Inherited from Control)
FindControl(String, Int32)

Searches the current naming container for a server control with the specified id and an integer, specified in the pathOffset parameter, which aids in the search. You should not override this version of the FindControl method.

(Inherited from Control)
Focus()

Sets input focus to a control.

(Inherited from Control)
GetDesignModeState()

Gets design-time data for a control.

(Inherited from Control)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetRouteUrl(Object)

Gets the URL that corresponds to a set of route parameters.

(Inherited from Control)
GetRouteUrl(RouteValueDictionary)

Gets the URL that corresponds to a set of route parameters.

(Inherited from Control)
GetRouteUrl(String, Object)

Gets the URL that corresponds to a set of route parameters and a route name.

(Inherited from Control)
GetRouteUrl(String, RouteValueDictionary)

Gets the URL that corresponds to a set of route parameters and a route name.

(Inherited from Control)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
GetUniqueIDRelativeTo(Control)

Returns the prefixed portion of the UniqueID property of the specified control.

(Inherited from Control)
HasControls()

Determines if the server control contains any child controls.

(Inherited from Control)
HasEvents()

Returns a value indicating whether events are registered for the control or any child controls.

(Inherited from Control)
IsLiteralContent()

Determines if the server control holds only literal content.

(Inherited from Control)
LoadControlState(Object)

Restores control-state information from a previous page request that was saved by the SaveControlState() method.

(Inherited from Control)
LoadViewState(Object)

Loads the previously saved view state of the DetailsView control.

MapPathSecure(String)

Retrieves the physical path that a virtual path, either absolute or relative, maps to.

(Inherited from Control)
MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
MergeStyle(Style)

Copies any nonblank elements of the specified style to the Web control, but will not overwrite any existing style elements of the control. This method is used primarily by control developers.

(Inherited from WebControl)
OnBubbleEvent(Object, EventArgs)

Determines whether the event for the server control is passed up the page's UI server control hierarchy.

(Inherited from Control)
OnDataBinding(EventArgs)

Raises the DataBinding event.

OnInit(EventArgs)

Raises the Init event.

(Inherited from Control)
OnLoad(EventArgs)

Raises the Load event.

(Inherited from Control)
OnPreRender(EventArgs)

Raises the PreRender event.

OnSelectedIndexChanged(EventArgs)

Raises the SelectedIndexChanged event. This allows you to provide a custom handler for the event.

OnTextChanged(EventArgs)

Raises the TextChanged event.

OnUnload(EventArgs)

Raises the Unload event.

(Inherited from Control)
OpenFile(String)

Gets a Stream used to read a file.

(Inherited from Control)
PerformDataBinding(IEnumerable)

Binds the specified data source to the control that is derived from the ListControl class.

PerformSelect()

Retrieves data from the associated data source.

RaiseBubbleEvent(Object, EventArgs)

Assigns any sources of the event and its information to the control's parent.

(Inherited from Control)
RemovedControl(Control)

Called after a child control is removed from the Controls collection of the Control object.

(Inherited from Control)
Render(HtmlTextWriter)

Renders the control to the specified HTML writer.

(Inherited from WebControl)
RenderBeginTag(HtmlTextWriter)

Renders the HTML opening tag of the control to the specified writer. This method is used primarily by control developers.

(Inherited from WebControl)
RenderChildren(HtmlTextWriter)

Outputs the content of a server control's children to a provided HtmlTextWriter object, which writes the content to be rendered on the client.

(Inherited from Control)
RenderContents(HtmlTextWriter)

Renders the items in the ListControl control.

RenderControl(HtmlTextWriter)

Outputs server control content to a provided HtmlTextWriter object and stores tracing information about the control if tracing is enabled.

(Inherited from Control)
RenderControl(HtmlTextWriter, ControlAdapter)

Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object.

(Inherited from Control)
RenderEndTag(HtmlTextWriter)

Renders the HTML closing tag of the control into the specified writer. This method is used primarily by control developers.

(Inherited from WebControl)
ResolveAdapter()

Gets the control adapter responsible for rendering the specified control.

(Inherited from Control)
ResolveClientUrl(String)

Gets a URL that can be used by the browser.

(Inherited from Control)
ResolveUrl(String)

Converts a URL into one that is usable on the requesting client.

(Inherited from Control)
SaveControlState()

Saves any server control state changes that have occurred since the time the page was posted back to the server.

(Inherited from Control)
SaveViewState()

Saves the current view state of the ListControl -derived control and the items it contains.

SetDesignModeState(IDictionary)

Sets design-time data for a control.

(Inherited from Control)
SetPostDataSelection(Int32)

Sets the Selected property of a ListItem control after a page is posted.

SetRenderMethodDelegate(RenderMethod)

Assigns an event handler delegate to render the server control and its content into its parent control.

(Inherited from Control)
SetTraceData(Object, Object)

Sets trace data for design-time tracing of rendering data, using the trace data key and the trace data value.

(Inherited from Control)
SetTraceData(Object, Object, Object)

Sets trace data for design-time tracing of rendering data, using the traced object, the trace data key, and the trace data value.

(Inherited from Control)
ToString()

Returns a string that represents the current object.

(Inherited from Object)
TrackViewState()

Marks the starting point to begin tracking and saving view-state changes to a ListControl -derived control.

VerifyMultiSelect()

Determines whether the list control supports multiselection mode.

Events

DataBinding

Occurs when the server control binds to a data source.

(Inherited from Control)
Disposed

Occurs when a server control is released from memory, which is the last stage of the server control lifecycle when an ASP.NET page is requested.

(Inherited from Control)
Init

Occurs when the server control is initialized, which is the first step in its lifecycle.

(Inherited from Control)
Load

Occurs when the server control is loaded into the Page object.

(Inherited from Control)
PreRender

Occurs after the Control object is loaded but prior to rendering.

(Inherited from Control)
SelectedIndexChanged

Occurs when the selection from the list control changes between posts to the server.

TextChanged

Occurs when the Text and SelectedValue properties change.

Unload

Occurs when the server control is unloaded from memory.

(Inherited from Control)

Explicit Interface Implementations

IAttributeAccessor.GetAttribute(String)

Gets an attribute of the Web control with the specified name.

(Inherited from WebControl)
IAttributeAccessor.SetAttribute(String, String)

Sets an attribute of the Web control to the specified name and value.

(Inherited from WebControl)
IControlBuilderAccessor.ControlBuilder

For a description of this member, see ControlBuilder.

(Inherited from Control)
IControlDesignerAccessor.GetDesignModeState()

For a description of this member, see GetDesignModeState().

(Inherited from Control)
IControlDesignerAccessor.SetDesignModeState(IDictionary)

For a description of this member, see SetDesignModeState(IDictionary).

(Inherited from Control)
IControlDesignerAccessor.SetOwnerControl(Control)

For a description of this member, see SetOwnerControl(Control).

(Inherited from Control)
IControlDesignerAccessor.UserData

For a description of this member, see UserData.

(Inherited from Control)
IDataBindingsAccessor.DataBindings

For a description of this member, see DataBindings.

(Inherited from Control)
IDataBindingsAccessor.HasDataBindings

For a description of this member, see HasDataBindings.

(Inherited from Control)
IExpressionsAccessor.Expressions

For a description of this member, see Expressions.

(Inherited from Control)
IExpressionsAccessor.HasExpressions

For a description of this member, see HasExpressions.

(Inherited from Control)
IParserAccessor.AddParsedSubObject(Object)

For a description of this member, see AddParsedSubObject(Object).

(Inherited from Control)

Extension Methods

FindDataSourceControl(Control)

Returns the data source that is associated with the data control for the specified control.

FindFieldTemplate(Control, String)

Returns the field template for the specified column in the specified control's naming container.

FindMetaTable(Control)

Returns the metatable object for the containing data control.

Applies to

See also