DropDownList Class
 

Represents a control that allows the user to select a single item from a drop-down list.

Namespace:   System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

Inheritance Hierarchy
SystemObject
   System.Web.UIControl
     System.Web.UI.WebControlsWebControl
       System.Web.UI.WebControlsBaseDataBoundControl
         System.Web.UI.WebControlsDataBoundControl
           System.Web.UI.WebControlsListControl
            System.Web.UI.WebControlsDropDownList

Syntax
[ValidationPropertyAttribute("SelectedItem")]
public class DropDownList : ListControl, IPostBackDataHandler
[ValidationPropertyAttribute("SelectedItem")]
public ref class DropDownList : ListControl, IPostBackDataHandler
[<ValidationPropertyAttribute("SelectedItem")>]
type DropDownList = 
    class
        inherit ListControl
        interface IPostBackDataHandler
    end
<ValidationPropertyAttribute("SelectedItem")>
Public Class DropDownList
	Inherits ListControl
	Implements IPostBackDataHandler
Constructors
NameDescription
System_CAPS_pubmethod DropDownList

Initializes a new instance of the DropDownList class.

Properties
NameDescription
System_CAPS_pubproperty

Gets or sets the access key that allows you to quickly navigate to the Web server control.(Inherited from WebControl.)

System_CAPS_protproperty

Gets the browser-specific adapter for the control.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets a value that indicates whether list items are cleared before data binding.(Inherited from ListControl.)

System_CAPS_pubproperty

Gets or sets the application-relative virtual directory of the Page or UserControl object that contains this control.(Inherited from Control.)

System_CAPS_pubproperty

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

System_CAPS_pubproperty

Gets or sets a value indicating whether a postback to the server automatically occurs when the user changes the list selection.(Inherited from ListControl.)

System_CAPS_pubproperty

Gets or sets the background color of the Web server control.(Inherited from WebControl.)

System_CAPS_pubproperty

This API supports the product infrastructure and is not intended to be used directly from your code. Gets the control that contains this control's data binding.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets the border color of the control.(Overrides .)

System_CAPS_pubproperty

Gets or sets the border style of the control.(Overrides .)

System_CAPS_pubproperty

Gets or sets the border width for the control.(Overrides .)

System_CAPS_pubproperty

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

System_CAPS_protproperty

Gets a value that indicates whether the server control's child controls have been created.(Inherited from Control.)

System_CAPS_pubproperty

Gets the control ID for HTML markup that is generated by ASP.NET.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets the algorithm that is used to generate the value of the property.(Inherited from Control.)

System_CAPS_protproperty

Gets a character value representing the separator character used in the property.(Inherited from Control.)

System_CAPS_protproperty

Gets the HttpContext object associated with the server control for the current Web request.(Inherited from Control.)

System_CAPS_pubproperty

Gets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy.(Inherited from Control.)

System_CAPS_pubproperty

Gets the style of the Web server control. This property is used primarily by control developers.(Inherited from WebControl.)

System_CAPS_pubproperty

Gets a value indicating whether a Style object has been created for the property. This property is primarily used by control developers.(Inherited from WebControl.)

System_CAPS_pubproperty

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

System_CAPS_pubproperty

Gets a reference to the naming container if the naming container implements IDataItemContainer.(Inherited from Control.)

System_CAPS_pubproperty

Gets a reference to the naming container if the naming container implements IDataKeysControl.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets the name of the list of data that the data-bound control binds to, in cases where the data source contains more than one distinct list of data items.(Inherited from DataBoundControl.)

System_CAPS_pubproperty

Gets or sets the object from which the data-bound control retrieves its list of data items.(Inherited from BaseDataBoundControl.)

System_CAPS_pubproperty

Gets or sets the ID of the control from which the data-bound control retrieves its list of data items.(Inherited from DataBoundControl.)

System_CAPS_pubproperty

Gets an object that implements the IDataSource interface, which provides access to the object's data content.(Inherited from DataBoundControl.)

System_CAPS_pubproperty

Gets or sets the field of the data source that provides the text content of the list items.(Inherited from ListControl.)

System_CAPS_pubproperty

Gets or sets the formatting string used to control how data bound to the list control is displayed.(Inherited from ListControl.)

System_CAPS_pubproperty

Gets or sets the field of the data source that provides the value of each list item.(Inherited from ListControl.)

System_CAPS_protproperty

Gets a value indicating whether a control is being used on a design surface.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets a value indicating whether the Web server control is enabled.(Inherited from WebControl.)

System_CAPS_pubproperty

Gets or sets a value indicating whether themes apply to this control.(Inherited from WebControl.)

System_CAPS_pubproperty

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.)

System_CAPS_protproperty

Gets a list of event handler delegates for the control. This property is read-only.(Inherited from Control.)

System_CAPS_pubproperty

Gets the font properties associated with the Web server control.(Inherited from WebControl.)

System_CAPS_pubproperty

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

System_CAPS_pubproperty

Gets a value indicating whether the control has attributes set.(Inherited from WebControl.)

System_CAPS_protproperty

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

System_CAPS_pubproperty

Gets or sets the height of the Web server control.(Inherited from WebControl.)

System_CAPS_pubproperty

Gets or sets the programmatic identifier assigned to the server control.(Inherited from Control.)

System_CAPS_protproperty

This API supports the product infrastructure and is not intended to be used directly from your code. Gets the character used to separate control identifiers.(Inherited from Control.)

System_CAPS_protproperty

Gets a value indicating whether the data-bound control has been initialized.(Inherited from BaseDataBoundControl.)

System_CAPS_protproperty

Gets a value indicating whether the property is set.(Inherited from BaseDataBoundControl.)

System_CAPS_protproperty

Gets a value indicating whether controls contained within this control have control state.(Inherited from Control.)

System_CAPS_protproperty

Gets a value that indicates whether data binding is automatic.(Inherited from BaseDataBoundControl.)

System_CAPS_protproperty

Gets a value indicating whether the control is enabled.(Inherited from WebControl.)

System_CAPS_protproperty

Gets a value that indicates whether the server control is saving changes to its view state.(Inherited from Control.)

System_CAPS_protproperty

Gets a value that indicates whether model binding is in use.(Inherited from DataBoundControl.)

System_CAPS_protproperty

Gets a value indicating whether view state is enabled for this control.(Inherited from Control.)

System_CAPS_pubproperty

Gets the collection of items in the list control.(Inherited from ListControl.)

System_CAPS_pubproperty

Gets or sets the name of the data item type for strongly typed data binding.(Inherited from DataBoundControl.)

System_CAPS_protproperty

Gets a value indicating whether the control participates in loading its view state by instead of index. (Inherited from Control.)

System_CAPS_pubproperty

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

System_CAPS_pubproperty

Gets a reference to the Page instance that contains the server control.(Inherited from Control.)

System_CAPS_pubproperty

Gets a reference to the server control's parent control in the page control hierarchy.(Inherited from Control.)

System_CAPS_pubproperty

Gets a value that specifies the ASP.NET version that rendered HTML will be compatible with.(Inherited from Control.)

System_CAPS_protproperty

Gets or sets a value indicating whether the DataBind method should be called. (Inherited from BaseDataBoundControl.)

System_CAPS_protproperty

Gets a DataSourceSelectArguments object that the data-bound control uses when retrieving data from a data source control. (Inherited from DataBoundControl.)

System_CAPS_pubproperty

Gets or sets the index of the selected item in the DropDownList control.(Overrides .)

System_CAPS_pubproperty

Gets the selected item with the lowest index in the list control.(Inherited from ListControl.)

System_CAPS_pubproperty

Gets the value of the selected item in the list control, or selects the item in the list control that contains the specified value.(Inherited from ListControl.)

System_CAPS_pubproperty

The name of the method to call in order to read data.(Inherited from DataBoundControl.)

System_CAPS_pubproperty

Gets information about the container that hosts the current control when rendered on a design surface.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets the skin to apply to the control.(Inherited from WebControl.)

System_CAPS_pubproperty

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.)

System_CAPS_pubproperty

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

System_CAPS_pubproperty

Gets or sets the tab index of the Web server control.(Inherited from WebControl.)

System_CAPS_protproperty

Gets the HtmlTextWriterTag value for the ListControl control. (Inherited from ListControl.)

System_CAPS_protproperty

Gets the name of the control tag. This property is used primarily by control developers.(Inherited from WebControl.)

System_CAPS_pubproperty

Gets or sets a reference to the template that contains this control. (Inherited from Control.)

System_CAPS_pubproperty

Gets the virtual directory of the Page or UserControl that contains the current server control.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets the property of the ListControl control.(Inherited from ListControl.)

System_CAPS_pubproperty

Gets or sets the text displayed when the mouse pointer hovers over the Web server control.(Inherited from WebControl.)

System_CAPS_pubproperty

Gets the unique, hierarchically qualified identifier for the server control.(Inherited from Control.)

System_CAPS_pubproperty

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

System_CAPS_pubproperty

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. (Inherited from ListControl.)

System_CAPS_protproperty

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.)

System_CAPS_protproperty

Gets a value that indicates whether the StateBag object is case-insensitive.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets the view-state mode of this control.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets a value that indicates whether a server control is rendered as UI on the page.(Inherited from Control.)

System_CAPS_pubproperty

Gets or sets the width of the Web server control.(Inherited from WebControl.)

Methods
NameDescription
System_CAPS_protmethod AddAttributesToRender

Adds HTML attributes and styles that need to be rendered to the specified HtmlTextWriter object.(Overrides ListControlAddAttributesToRender.)

System_CAPS_protmethod AddedControl

Called after a child control is added to the collection of the Control object.(Inherited from Control.)

System_CAPS_protmethod AddParsedSubObject

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.)

System_CAPS_pubmethod ApplyStyle

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.)

System_CAPS_pubmethod ApplyStyleSheetSkin

Applies the style properties defined in the page style sheet to the control.(Inherited from Control.)

System_CAPS_protmethod BeginRenderTracing

Begins design-time tracing of rendering data.(Inherited from Control.)

System_CAPS_protmethod BuildProfileTree

This API supports the product infrastructure and is not intended to be used directly from your code. Gathers information about the server control and delivers it to the property to be displayed when tracing is enabled for the page.(Inherited from Control.)

System_CAPS_protmethod ClearCachedClientID

This API supports the product infrastructure and is not intended to be used directly from your code. Sets the cached value to null.(Inherited from Control.)

System_CAPS_protmethod ClearChildControlState

Deletes the control-state information for the server control's child controls. (Inherited from Control.)

System_CAPS_protmethod ClearChildState

Deletes the view-state and control-state information for all the server control's child controls.(Inherited from Control.)

System_CAPS_protmethod ClearChildViewState

Deletes the view-state information for all the server control's child controls.(Inherited from Control.)

System_CAPS_protmethod ClearEffectiveClientIDMode

This API supports the product infrastructure and is not intended to be used directly from your code. Sets the property of the current control instance and of any child controls to Inherit.(Inherited from Control.)

System_CAPS_pubmethod ClearSelection

Clears out the list selection and sets the property of all items to false.(Inherited from ListControl.)

System_CAPS_protmethod ConfirmInitState

Sets the initialized state of the data-bound control.(Inherited from BaseDataBoundControl.)

System_CAPS_pubmethod CopyBaseAttributes

Copies the properties not encapsulated by the 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.)

System_CAPS_protmethod 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.)

System_CAPS_protmethod CreateControlCollection

Creates a collection to store child controls.(Overrides ControlCreateControlCollection.)

System_CAPS_protmethod 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.)

System_CAPS_protmethod CreateDataSourceSelectArguments

Creates a default DataSourceSelectArguments object used by the data-bound control if no arguments are specified.(Inherited from DataBoundControl.)

System_CAPS_pubmethod DataBind

Binds a data source to the invoked server control and all its child controls.(Inherited from BaseDataBoundControl.)

System_CAPS_protmethod DataBind

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.)

System_CAPS_protmethod DataBindChildren

Binds a data source to the server control's child controls.(Inherited from Control.)

System_CAPS_pubmethod Dispose

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

System_CAPS_protmethod EndRenderTracing

Ends design-time tracing of rendering data.(Inherited from Control.)

System_CAPS_protmethod EnsureChildControls

Determines whether the server control contains child controls. If it does not, it creates child controls.(Inherited from Control.)

System_CAPS_protmethod EnsureDataBound

Calls the DataBind method if the property is set and the data-bound control is marked to require binding.(Inherited from BaseDataBoundControl.)

System_CAPS_protmethod EnsureID

Creates an identifier for controls that do not have an identifier assigned.(Inherited from Control.)

System_CAPS_pubmethod Equals

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethod Finalize

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethod FindControl

Searches the current naming container for a server control with the specified id parameter.(Inherited from Control.)

System_CAPS_protmethod FindControl

This API supports the product infrastructure and is not intended to be used directly from your code. 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.)

System_CAPS_pubmethod Focus

Sets input focus to a control.(Inherited from Control.)

System_CAPS_protmethod GetData

Retrieves a DataSourceView object that the data-bound control uses to perform data operations.(Inherited from DataBoundControl.)

System_CAPS_protmethod GetDataSource

Retrieves the IDataSource interface that the data-bound control is associated with, if any.(Inherited from DataBoundControl.)

System_CAPS_protmethod GetDesignModeState

This API supports the product infrastructure and is not intended to be used directly from your code. Gets design-time data for a control.(Inherited from Control.)

System_CAPS_pubmethod GetHashCode

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethod GetRouteUrl

Gets the URL that corresponds to a set of route parameters.(Inherited from Control.)

System_CAPS_pubmethod GetRouteUrl

Gets the URL that corresponds to a set of route parameters.(Inherited from Control.)

System_CAPS_pubmethod GetRouteUrl

Gets the URL that corresponds to a set of route parameters and a route name.(Inherited from Control.)

System_CAPS_pubmethod GetRouteUrl

Gets the URL that corresponds to a set of route parameters and a route name.(Inherited from Control.)

System_CAPS_pubmethod GetType

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethod GetUniqueIDRelativeTo

Returns the prefixed portion of the property of the specified control.(Inherited from Control.)

System_CAPS_pubmethod HasControls

Determines if the server control contains any child controls.(Inherited from Control.)

System_CAPS_protmethod HasEvents

Returns a value indicating whether events are registered for the control or any child controls.(Inherited from Control.)

System_CAPS_protmethod IsLiteralContent

This API supports the product infrastructure and is not intended to be used directly from your code. Determines if the server control holds only literal content.(Inherited from Control.)

System_CAPS_protmethod LoadControlState

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

System_CAPS_protmethod LoadPostData

Processes postback data for the DropDownList control.

System_CAPS_protmethod LoadViewState

Loads the previously saved view state of the DetailsView control.(Inherited from ListControl.)

System_CAPS_protmethod MapPathSecure

Retrieves the physical path that a virtual path, either absolute or relative, maps to.(Inherited from Control.)

System_CAPS_protmethod MarkAsDataBound

Sets the state of the control in view state as successfully bound to data.(Inherited from DataBoundControl.)

System_CAPS_protmethod MemberwiseClone

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethod MergeStyle

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.)

System_CAPS_protmethod OnBubbleEvent

Determines whether the event for the server control is passed up the page's UI server control hierarchy.(Inherited from Control.)

System_CAPS_protmethod OnCreatingModelDataSource

Raises the CreatingModelDataSource event.(Inherited from DataBoundControl.)

System_CAPS_protmethod OnDataBinding

This API supports the product infrastructure and is not intended to be used directly from your code. Raises the DataBinding event.(Inherited from ListControl.)

System_CAPS_protmethod OnDataBound

Raises the DataBound event.(Inherited from BaseDataBoundControl.)

System_CAPS_protmethod OnDataPropertyChanged

Rebinds the data-bound control to its data after one of the base data source identification properties changes.(Inherited from DataBoundControl.)

System_CAPS_protmethod OnDataSourceViewChanged

Raises the DataSourceViewChanged event.(Inherited from DataBoundControl.)

System_CAPS_protmethod OnInit

Handles the Init event.(Inherited from BaseDataBoundControl.)

System_CAPS_protmethod OnLoad

Handles the ControlLoad event.(Inherited from DataBoundControl.)

System_CAPS_protmethod OnPagePreLoad

Sets the initialized state of the data-bound control before the control is loaded.(Inherited from DataBoundControl.)

System_CAPS_protmethod OnPreRender

Raises the PreRender event.(Inherited from ListControl.)

System_CAPS_protmethod OnSelectedIndexChanged

Raises the SelectedIndexChanged event. This allows you to provide a custom handler for the event.(Inherited from ListControl.)

System_CAPS_protmethod OnTextChanged

Raises the TextChanged event.(Inherited from ListControl.)

System_CAPS_protmethod OnUnload

Raises the Unload event.(Inherited from Control.)

System_CAPS_protmethod OpenFile

Gets a Stream used to read a file.(Inherited from Control.)

System_CAPS_protmethod PerformDataBinding

This API supports the product infrastructure and is not intended to be used directly from your code. Binds the specified data source to the control that is derived from the ListControl class.(Inherited from ListControl.)

System_CAPS_protmethod PerformSelect

Retrieves data from the associated data source.(Inherited from ListControl.)

System_CAPS_protmethod RaiseBubbleEvent

Assigns any sources of the event and its information to the control's parent.(Inherited from Control.)

System_CAPS_protmethod RaisePostDataChangedEvent

Raises events for the DropDownList control when postback occurs.

System_CAPS_protmethod RemovedControl

Called after a child control is removed from the collection of the Control object.(Inherited from Control.)

System_CAPS_protmethod Render

Renders the control to the specified HTML writer.(Inherited from WebControl.)

System_CAPS_pubmethod RenderBeginTag

Renders the HTML opening tag of the control to the specified writer. This method is used primarily by control developers.(Inherited from WebControl.)

System_CAPS_protmethod RenderChildren

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.)

System_CAPS_protmethod RenderContents

Renders the items in the ListControl control.(Inherited from ListControl.)

System_CAPS_pubmethod RenderControl

Outputs server control content to a provided HtmlTextWriter object and stores tracing information about the control if tracing is enabled.(Inherited from Control.)

System_CAPS_protmethod RenderControl

Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object.(Inherited from Control.)

System_CAPS_pubmethod RenderEndTag

Renders the HTML closing tag of the control into the specified writer. This method is used primarily by control developers.(Inherited from WebControl.)

System_CAPS_protmethod ResolveAdapter

Gets the control adapter responsible for rendering the specified control.(Inherited from Control.)

System_CAPS_pubmethod ResolveClientUrl

Gets a URL that can be used by the browser.(Inherited from Control.)

System_CAPS_pubmethod ResolveUrl

Converts a URL into one that is usable on the requesting client.(Inherited from Control.)

System_CAPS_protmethod SaveControlState

Saves any server control state changes that have occurred since the time the page was posted back to the server.(Inherited from Control.)

System_CAPS_protmethod SaveViewState

Saves the current view state of the ListControl -derived control and the items it contains.(Inherited from ListControl.)

System_CAPS_protmethod SetDesignModeState

Sets design-time data for a control.(Inherited from Control.)

System_CAPS_protmethod SetPostDataSelection

This API supports the product infrastructure and is not intended to be used directly from your code. Sets the property of a ListItem control after a page is posted.(Inherited from ListControl.)

System_CAPS_pubmethod SetRenderMethodDelegate

This API supports the product infrastructure and is not intended to be used directly from your code. Assigns an event handler delegate to render the server control and its content into its parent control.(Inherited from Control.)

System_CAPS_pubmethod SetTraceData

Sets trace data for design-time tracing of rendering data, using the trace data key and the trace data value.(Inherited from Control.)

System_CAPS_pubmethod SetTraceData

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.)

System_CAPS_pubmethod ToString

Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_protmethod TrackViewState

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

System_CAPS_protmethod ValidateDataSource

Verifies that the object a data-bound control binds to is one it can work with.(Inherited from DataBoundControl.)

System_CAPS_protmethod VerifyMultiSelect

Always throws an HttpException exception because multiple selection is not supported for the DropDownList control.(Overrides ListControlVerifyMultiSelect.)

Events
NameDescription
System_CAPS_pubevent CallingDataMethods

Occurs when data methods are being called.(Inherited from DataBoundControl.)

System_CAPS_pubevent CreatingModelDataSource

Occurs when the ModelDataSource object is being created.(Inherited from DataBoundControl.)

System_CAPS_pubevent DataBinding

Occurs when the server control binds to a data source.(Inherited from Control.)

System_CAPS_pubevent DataBound

Occurs after the server control binds to a data source.(Inherited from BaseDataBoundControl.)

System_CAPS_pubevent 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.)

System_CAPS_pubevent Init

Occurs when the server control is initialized, which is the first step in its lifecycle.(Inherited from Control.)

System_CAPS_pubevent Load

Occurs when the server control is loaded into the Page object.(Inherited from Control.)

System_CAPS_pubevent PreRender

Occurs after the Control object is loaded but prior to rendering.(Inherited from Control.)

System_CAPS_pubevent SelectedIndexChanged

Occurs when the selection from the list control changes between posts to the server.(Inherited from ListControl.)

System_CAPS_pubevent TextChanged

Occurs when the and properties change.(Inherited from ListControl.)

System_CAPS_pubevent Unload

Occurs when the server control is unloaded from memory.(Inherited from Control.)

Explicit Interface Implementations
NameDescription
System_CAPS_pubinterface System_CAPS_privmethod IAttributeAccessorGetAttribute

This API supports the product infrastructure and is not intended to be used directly from your code. Gets an attribute of the Web control with the specified name.(Inherited from WebControl.)

System_CAPS_pubinterface System_CAPS_privmethod IAttributeAccessorSetAttribute

Sets an attribute of the Web control to the specified name and value.(Inherited from WebControl.)

System_CAPS_pubinterface System_CAPS_privmethod IControlDesignerAccessorGetDesignModeState

For a description of this member, see IControlDesignerAccessorGetDesignModeState.(Inherited from Control.)

System_CAPS_pubinterface System_CAPS_privmethod IControlDesignerAccessorSetDesignModeState

For a description of this member, see IControlDesignerAccessorSetDesignModeState. (Inherited from Control.)

System_CAPS_pubinterface System_CAPS_privmethod IControlDesignerAccessorSetOwnerControl

This API supports the product infrastructure and is not intended to be used directly from your code. For a description of this member, see IControlDesignerAccessorSetOwnerControl. (Inherited from Control.)

System_CAPS_pubinterface System_CAPS_privmethod IParserAccessorAddParsedSubObject

For a description of this member, see IParserAccessorAddParsedSubObject. (Inherited from Control.)

System_CAPS_pubinterface System_CAPS_privmethod IPostBackDataHandlerLoadPostData

This API supports the product infrastructure and is not intended to be used directly from your code. Processes posted data for the DropDownList control.

System_CAPS_pubinterface System_CAPS_privmethod IPostBackDataHandlerRaisePostDataChangedEvent

This API supports the product infrastructure and is not intended to be used directly from your code. Raises events for the DropDownList control on postback.

System_CAPS_pubinterface System_CAPS_privproperty

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

System_CAPS_pubinterface System_CAPS_privproperty

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

System_CAPS_pubinterface System_CAPS_privproperty

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

System_CAPS_pubinterface System_CAPS_privproperty

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

System_CAPS_pubinterface System_CAPS_privproperty

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

System_CAPS_pubinterface System_CAPS_privproperty

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

Extension Methods
NameDescription
System_CAPS_pubmethod EnablePersistedSelection

Obsolete.Enables selection to be persisted in data controls that support selection and paging.(Defined by DynamicDataExtensions.)

System_CAPS_pubmethod FindDataSourceControl

Returns the data source that is associated with the data control for the specified control.(Defined by DynamicDataExtensions.)

System_CAPS_pubmethod FindFieldTemplate

Returns the field template for the specified column in the specified control's naming container.(Defined by DynamicDataExtensions.)

System_CAPS_pubmethod FindMetaTable

Returns the metatable object for the containing data control.(Defined by DynamicDataExtensions.)

Remarks

In this topic:

  • Introduction

  • Accessibility

  • Declarative Syntax

Introduction

Use the DropDownList control to create a single-selection drop-down list control. You can control the appearance of the DropDownList control by setting the , , and properties.

To specify the items that you want to appear in the DropDownList control, place a ListItem object for each entry between the opening and closing tags of the DropDownList control.

The DropDownList control also supports data binding. To bind the control to a data source, create a data source, such as a System.CollectionsArrayList object, that contains the items to display in the control. Then, use the ControlDataBind method to bind the data source to the DropDownList control.

Use the property to programmatically determine the index of the item selected by the user from the DropDownList control. The index can then be used to retrieve the selected item from the Items collection of the control.

Accessibility

For information about how to configure this control so that it generates markup that conforms to accessibility standards, see Accessibility in Visual Studio and ASP.NET and ASP.NET Controls and Accessibility.

Declarative Syntax
<asp:DropDownList
    AccessKey="string"
    AppendDataBoundItems="True|False"
    AutoPostBack="True|False"
    BackColor="color name|#dddddd"
    BorderColor="color name|#dddddd"
    BorderStyle="NotSet|None|Dotted|Dashed|Solid|Double|Groove|Ridge|
        Inset|Outset"
    BorderWidth="size"
    CausesValidation="True|False"
    CssClass="string"
    DataMember="string"
    DataSource="string"
    DataSourceID="string"
    DataTextField="string"
    DataTextFormatString="string"
    DataValueField="string"
    Enabled="True|False"
    EnableTheming="True|False"
    EnableViewState="True|False"
    Font-Bold="True|False"
    Font-Italic="True|False"
    Font-Names="string"
    Font-Overline="True|False"
    Font-Size="string|Smaller|Larger|XX-Small|X-Small|Small|Medium|
        Large|X-Large|XX-Large"
    Font-Strikeout="True|False"
    Font-Underline="True|False"
    ForeColor="color name|#dddddd"
    Height="size"
    ID="string"
    OnDataBinding="DataBinding event handler"
    OnDataBound="DataBound event handler"
    OnDisposed="Disposed event handler"
    OnInit="Init event handler"
    OnLoad="Load event handler"
    OnPreRender="PreRender event handler"
    OnSelectedIndexChanged="SelectedIndexChanged event handler"
    OnTextChanged="TextChanged event handler"
    OnUnload="Unload event handler"
    runat="server"
    SelectedIndex="integer"
    SelectedValue="string"
    SkinID="string"
    Style="string"
    TabIndex="integer"
    ToolTip="string"
    ValidationGroup="string"
    Visible="True|False"
    Width="size"
>
            <asp:ListItem
                Enabled="True|False"
                Selected="True|False"
                Text="string"
                Value="string"
            />
</asp:DropDownList>
Examples

A Visual Studio Web site project with source code is available to accompany this topic: Download.

The following code example demonstrates how to create a DropDownList control that contains four items.

<%@ 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" >
   <script runat="server" >

      void Selection_Change(Object sender, EventArgs e)
      {

         // Set the background color for days in the Calendar control
         // based on the value selected by the user from the 
         // DropDownList control.
         Calendar1.DayStyle.BackColor = 
             System.Drawing.Color.FromName(ColorList.SelectedItem.Value);

      }

   </script>

<head runat="server">
    <title> DropDownList Example </title>
</head>
<body>

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

      <h3> DropDownList Example </h3>

      Select a background color for days in the calendar.

      <br /><br /> 

      <asp:Calendar id="Calendar1"
           ShowGridLines="True" 
           ShowTitle="True"
           runat="server"/>

      <br /><br />

      <table cellpadding="5">

         <tr>

            <td>

               Background color:

            </td>

         </tr>

         <tr>

            <td>

               <asp:DropDownList id="ColorList"
                    AutoPostBack="True"
                    OnSelectedIndexChanged="Selection_Change"
                    runat="server">

                  <asp:ListItem Selected="True" Value="White"> White </asp:ListItem>
                  <asp:ListItem Value="Silver"> Silver </asp:ListItem>
                  <asp:ListItem Value="DarkGray"> Dark Gray </asp:ListItem>
                  <asp:ListItem Value="Khaki"> Khaki </asp:ListItem>
                  <asp:ListItem Value="DarkKhaki"> Dark Khaki </asp:ListItem>

               </asp:DropDownList>

            </td>

         </tr>

      </table>

   </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" >
   <script runat="server" >

      Sub Selection_Change(sender As Object, e As EventArgs)

         ' Set the background color for days in the Calendar control
         ' based on the value selected by the user from the
         '  DropDownList control.
         Calendar1.DayStyle.BackColor = _
             System.Drawing.Color.FromName(ColorList.SelectedItem.Value)

      End Sub

   </script>

<head runat="server">
    <title> DropDownList Example </title>
</head>
<body>

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

      <h3> DropDownList Example </h3>

      Select a background color for days in the calendar.

      <br /><br /> 

      <asp:Calendar id="Calendar1"
           ShowGridLines="True" 
           ShowTitle="True"
           runat="server"/>

      <br /><br />

      <table cellpadding="5">

         <tr>

            <td>

               Background color:

            </td>

         </tr>

         <tr>

            <td>

               <asp:DropDownList id="ColorList"
                    AutoPostBack="True"
                    OnSelectedIndexChanged="Selection_Change"
                    runat="server">

                  <asp:ListItem Selected="True" Value="White"> White </asp:ListItem>
                  <asp:ListItem Value="Silver"> Silver </asp:ListItem>
                  <asp:ListItem Value="DarkGray"> Dark Gray </asp:ListItem>
                  <asp:ListItem Value="Khaki"> Khaki </asp:ListItem>
                  <asp:ListItem Value="DarkKhaki"> Dark Khaki </asp:ListItem>

               </asp:DropDownList>

            </td>

         </tr>

      </table>   

   </form>

</body>
</html>

The following code example demonstrates how to create a DropDownList control though data binding.

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<!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" >
   <script runat="server" >

      void Selection_Change(Object sender, EventArgs e)
      {

         // Set the background color for days in the Calendar control
         // based on the value selected by the user from the 
         // DropDownList control.
         Calendar1.DayStyle.BackColor = 
             System.Drawing.Color.FromName(ColorList.SelectedItem.Value);

      }

      void Page_Load(Object sender, EventArgs e)
      {

         // Load data for the DropDownList control only once, when the 
         // page is first loaded.
         if(!IsPostBack)
         {

            // Specify the data source and field names for the Text 
            // and Value properties of the items (ListItem objects) 
            // in the DropDownList control.
            ColorList.DataSource = CreateDataSource();
            ColorList.DataTextField = "ColorTextField";
            ColorList.DataValueField = "ColorValueField";

            // Bind the data to the control.
            ColorList.DataBind();

            // Set the default selected item, if desired.
            ColorList.SelectedIndex = 0;

         }

      }

      ICollection CreateDataSource() 
      {

         // Create a table to store data for the DropDownList control.
         DataTable dt = new DataTable();

         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("ColorTextField", typeof(String)));
         dt.Columns.Add(new DataColumn("ColorValueField", typeof(String)));

         // Populate the table with sample values.
         dt.Rows.Add(CreateRow("White", "White", dt));
         dt.Rows.Add(CreateRow("Silver", "Silver", dt));
         dt.Rows.Add(CreateRow("Dark Gray", "DarkGray", dt));
         dt.Rows.Add(CreateRow("Khaki", "Khaki", dt));
         dt.Rows.Add(CreateRow("Dark Khaki", "DarkKhaki", dt));

         // Create a DataView from the DataTable to act as the data source
         // for the DropDownList control.
         DataView dv = new DataView(dt);
         return dv;

      }

      DataRow CreateRow(String Text, String Value, DataTable dt)
      {

         // Create a DataRow using the DataTable defined in the 
         // CreateDataSource method.
         DataRow dr = dt.NewRow();

         // This DataRow contains the ColorTextField and ColorValueField 
         // fields, as defined in the CreateDataSource method. Set the 
         // fields with the appropriate value. Remember that column 0 
         // is defined as ColorTextField, and column 1 is defined as 
         // ColorValueField.
         dr[0] = Text;
         dr[1] = Value;

         return dr;

      }

   </script>

<head runat="server">
    <title> DropDownList Data Binding Example </title>
</head>
<body>

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

      <h3> DropDownList Data Binding Example </h3>

      Select a background color for days in the calendar.

      <br /><br /> 

      <asp:Calendar id="Calendar1"
           ShowGridLines="True" 
           ShowTitle="True"
           runat="server"/>

      <br /><br />

      <table cellpadding="5">

         <tr>

            <td>

               Background color:

            </td>

         </tr>

         <tr>

            <td>

               <asp:DropDownList id="ColorList"
                    AutoPostBack="True"
                    OnSelectedIndexChanged="Selection_Change"
                    runat="server"/>

            </td>

         </tr>

      </table>   

   </form>

</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<!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" >
   <script runat="server" >

      Sub Selection_Change(sender as Object, e As EventArgs)

         ' Set the background color for days in the Calendar control 
         ' based on the value selected by the user from the
         ' DropDownList control.
         Calendar1.DayStyle.BackColor = _
             System.Drawing.Color.FromName(ColorList.SelectedItem.Value)

      End Sub

      Sub Page_Load(sender as Object, e As EventArgs)

         ' Load data for the DropDownList control only once, when the 
         ' page is first loaded.
         If Not IsPostBack Then

            ' Specify the data source and field names for the Text 
            ' and Value properties of the items (ListItem objects)
            ' in the DropDownList control.
            ColorList.DataSource = CreateDataSource()
            ColorList.DataTextField = "ColorTextField"
            ColorList.DataValueField = "ColorValueField"

            ' Bind the data to the control.
            ColorList.DataBind()

            ' Set the default selected item, if desired.
            ColorList.SelectedIndex = 0

         End If

      End Sub

      Function CreateDataSource() As ICollection 

         ' Create a table to store data for the DropDownList control.
         Dim dt As DataTable = New DataTable()

         ' Define the columns of the table.
         dt.Columns.Add(new DataColumn("ColorTextField", GetType(String)))
         dt.Columns.Add(new DataColumn("ColorValueField", GetType(String)))

         ' Populate the table with sample values.
         dt.Rows.Add(CreateRow("White", "White", dt))
         dt.Rows.Add(CreateRow("Silver", "Silver", dt))
         dt.Rows.Add(CreateRow("Dark Gray", "DarkGray", dt))
         dt.Rows.Add(CreateRow("Khaki", "Khaki", dt))
         dt.Rows.Add(CreateRow("Dark Khaki", "DarkKhaki", dt))

         ' Create a DataView from the DataTable to act as the data source
         ' for the DropDownList control.
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function

      Function CreateRow(Text As String, Value As String, dt As DataTable) As DataRow 

         ' Create a DataRow using the DataTable defined in the 
         ' CreateDataSource method.
         Dim dr As DataRow = dt.NewRow()

         ' This DataRow contains the ColorTextField and ColorValueField 
         ' fields, as defined in the CreateDataSource method. Set the 
         ' fields with the appropriate value. Remember that column 0 
         ' is defined as ColorTextField, and column 1 is defined as 
         ' ColorValueField.
         dr(0) = Text
         dr(1) = Value

         Return dr

      End Function

   </script>

<head runat="server">
    <title> DropDownList Data Binding Example </title>
</head>
<body>

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

      <h3> DropDownList Data Binding Example </h3>

      Select a background color for days in the calendar.

      <br /><br /> 

      <asp:Calendar id="Calendar1"
           ShowGridLines="True" 
           ShowTitle="True"
           runat="server"/>

      <br /><br />

      <table cellpadding="5">

         <tr>

            <td>

               Background color:

            </td>

         </tr>

         <tr>

            <td>

               <asp:DropDownList id="ColorList"
                    AutoPostBack="True"
                    OnSelectedIndexChanged="Selection_Change"
                    runat="server"/>

            </td>

         </tr>

      </table>   

   </form>

</body>
</html>
Version Information
.NET Framework
Available since 1.1
Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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