.NET Framework Class Library
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)
Syntax
<[%$TOPIC/e0ybx34e_en-us_VS_110_2_0_0_0_0%]("SelectedItem")> _
Public Class DropDownList _
	Inherits [%$TOPIC/e0ybx34e_en-us_VS_110_2_0_0_0_1%] _
	Implements [%$TOPIC/e0ybx34e_en-us_VS_110_2_0_0_0_2%]
[[%$TOPIC/e0ybx34e_en-us_VS_110_2_0_1_0_0%]("SelectedItem")]
public class DropDownList : [%$TOPIC/e0ybx34e_en-us_VS_110_2_0_1_0_1%], 
	[%$TOPIC/e0ybx34e_en-us_VS_110_2_0_1_0_2%]
[[%$TOPIC/e0ybx34e_en-us_VS_110_2_0_2_0_0%](L"SelectedItem")]
public ref class DropDownList : public [%$TOPIC/e0ybx34e_en-us_VS_110_2_0_2_0_1%], 
	[%$TOPIC/e0ybx34e_en-us_VS_110_2_0_2_0_2%]
[<[%$TOPIC/e0ybx34e_en-us_VS_110_2_0_3_0_0%]("SelectedItem")>]
type DropDownList =  
    class 
        inherit [%$TOPIC/e0ybx34e_en-us_VS_110_2_0_3_0_1%] 
        interface [%$TOPIC/e0ybx34e_en-us_VS_110_2_0_3_0_2%] 
    end
<asp:DropDownList />

The DropDownList type exposes the following members.

Constructors
  NameDescription
Public method DropDownListInitializes a new instance of the DropDownList class.
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Properties
  NameDescription
Public property AccessKeyGets or sets the access key that allows you to quickly navigate to the Web server control. (Inherited from WebControl.)
Protected property AdapterGets the browser-specific adapter for the control. (Inherited from Control.)
Public property AppendDataBoundItemsGets or sets a value that indicates whether list items are cleared before data binding. (Inherited from ListControl.)
Public property AppRelativeTemplateSourceDirectoryGets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. (Inherited from Control.)
Public property AttributesGets the collection of arbitrary attributes (for rendering only) that do not correspond to properties on the control. (Inherited from WebControl.)
Public property AutoPostBackGets or sets a value indicating whether a postback to the server automatically occurs when the user changes the list selection. (Inherited from ListControl.)
Public property BackColorGets or sets the background color of the Web server control. (Inherited from WebControl.)
Public property BindingContainerInfrastructure. Gets the control that contains this control's data binding. (Inherited from Control.)
Public property BorderColorGets or sets the border color of the control. (Overrides WebControlBorderColor.)
Public property BorderStyleGets or sets the border style of the control. (Overrides WebControlBorderStyle.)
Public property BorderWidthGets or sets the border width for the control. (Overrides WebControlBorderWidth.)
Public property CausesValidationGets or sets a value indicating whether validation is performed when a control that is derived from the ListControl class is clicked. (Inherited from ListControl.)
Protected property ChildControlsCreatedGets a value that indicates whether the server control's child controls have been created. (Inherited from Control.)
Public property ClientIDGets the control ID for HTML markup that is generated by ASP.NET. (Inherited from Control.)
Public property ClientIDModeGets or sets the algorithm that is used to generate the value of the ClientID property. (Inherited from Control.)
Protected property ClientIDSeparatorGets a character value representing the separator character used in the ClientID property. (Inherited from Control.)
Protected property ContextGets the HttpContext object associated with the server control for the current Web request. (Inherited from Control.)
Public property ControlsGets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy. (Inherited from Control.)
Public property ControlStyleGets the style of the Web server control. This property is used primarily by control developers. (Inherited from WebControl.)
Public property ControlStyleCreatedGets 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.)
Public property CssClassGets or sets the Cascading Style Sheet (CSS) class rendered by the Web server control on the client. (Inherited from WebControl.)
Public property DataItemContainerGets a reference to the naming container if the naming container implements IDataItemContainer. (Inherited from Control.)
Public property DataKeysContainerGets a reference to the naming container if the naming container implements IDataKeysControl. (Inherited from Control.)
Public property DataMemberGets 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.)
Public property DataSourceGets or sets the object from which the data-bound control retrieves its list of data items. (Inherited from BaseDataBoundControl.)
Public property DataSourceIDGets or sets the ID of the control from which the data-bound control retrieves its list of data items. (Inherited from DataBoundControl.)
Public property DataSourceObjectGets an object that implements the IDataSource interface, which provides access to the object's data content. (Inherited from DataBoundControl.)
Public property DataTextFieldGets or sets the field of the data source that provides the text content of the list items. (Inherited from ListControl.)
Public property DataTextFormatStringGets or sets the formatting string used to control how data bound to the list control is displayed. (Inherited from ListControl.)
Public property DataValueFieldGets or sets the field of the data source that provides the value of each list item. (Inherited from ListControl.)
Protected property DesignModeGets a value indicating whether a control is being used on a design surface. (Inherited from Control.)
Public property EnabledGets or sets a value indicating whether the Web server control is enabled. (Inherited from WebControl.)
Public property EnableThemingGets or sets a value indicating whether themes apply to this control. (Inherited from WebControl.)
Public property EnableViewStateGets 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.)
Protected property EventsGets a list of event handler delegates for the control. This property is read-only. (Inherited from Control.)
Public property FontGets the font properties associated with the Web server control. (Inherited from WebControl.)
Public property ForeColorGets or sets the foreground color (typically the color of the text) of the Web server control. (Inherited from WebControl.)
Public property HasAttributesGets a value indicating whether the control has attributes set. (Inherited from WebControl.)
Protected property HasChildViewStateGets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control.)
Public property HeightGets or sets the height of the Web server control. (Inherited from WebControl.)
Public property IDGets or sets the programmatic identifier assigned to the server control. (Inherited from Control.)
Protected property IdSeparatorInfrastructure. Gets the character used to separate control identifiers. (Inherited from Control.)
Protected property InitializedGets a value indicating whether the data-bound control has been initialized. (Inherited from BaseDataBoundControl.)
Protected property IsBoundUsingDataSourceIDGets a value indicating whether the DataSourceID property is set. (Inherited from BaseDataBoundControl.)
Protected property IsChildControlStateClearedGets a value indicating whether controls contained within this control have control state. (Inherited from Control.)
Protected property IsDataBindingAutomaticGets a value that indicates whether data binding is automatic. (Inherited from BaseDataBoundControl.)
Protected property IsEnabledGets a value indicating whether the control is enabled. (Inherited from WebControl.)
Protected property IsTrackingViewStateGets a value that indicates whether the server control is saving changes to its view state. (Inherited from Control.)
Protected property IsUsingModelBindersGets a value that indicates whether model binding is in use. (Inherited from DataBoundControl.)
Protected property IsViewStateEnabledGets a value indicating whether view state is enabled for this control. (Inherited from Control.)
Public property ItemsGets the collection of items in the list control. (Inherited from ListControl.)
Public property ItemTypeGets or sets the name of the data item type for strongly typed data binding. (Inherited from DataBoundControl.)
Protected property LoadViewStateByIDGets a value indicating whether the control participates in loading its view state by ID instead of index. (Inherited from Control.)
Public property NamingContainerGets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same ControlID property value. (Inherited from Control.)
Public property PageGets a reference to the Page instance that contains the server control. (Inherited from Control.)
Public property ParentGets a reference to the server control's parent control in the page control hierarchy. (Inherited from Control.)
Public property RenderingCompatibilityGets a value that specifies the ASP.NET version that rendered HTML will be compatible with. (Inherited from Control.)
Protected property RequiresDataBindingGets or sets a value indicating whether the DataBind method should be called. (Inherited from BaseDataBoundControl.)
Protected property SelectArgumentsGets a DataSourceSelectArguments object that the data-bound control uses when retrieving data from a data source control. (Inherited from DataBoundControl.)
Public property SelectedIndexGets or sets the index of the selected item in the DropDownList control. (Overrides ListControlSelectedIndex.)
Public property SelectedItemGets the selected item with the lowest index in the list control. (Inherited from ListControl.)
Public property SelectedValueGets 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.)
Public property SelectMethodThe name of the method to call in order to read data. (Inherited from DataBoundControl.)
Public property SiteGets information about the container that hosts the current control when rendered on a design surface. (Inherited from Control.)
Public property SkinIDGets or sets the skin to apply to the control. (Inherited from WebControl.)
Public property StyleGets 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.)
Public property SupportsDisabledAttributeGets 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. (Overrides BaseDataBoundControlSupportsDisabledAttribute.)
Public property TabIndexGets or sets the tab index of the Web server control. (Inherited from WebControl.)
Protected property TagKeyGets the HtmlTextWriterTag value for the ListControl control. (Inherited from ListControl.)
Protected property TagNameGets the name of the control tag. This property is used primarily by control developers. (Inherited from WebControl.)
Public property TemplateControlGets or sets a reference to the template that contains this control. (Inherited from Control.)
Public property TemplateSourceDirectoryGets the virtual directory of the Page or UserControl that contains the current server control. (Inherited from Control.)
Public property TextGets or sets the SelectedValue property of the ListControl control. (Inherited from ListControl.)
Public property ToolTipGets or sets the text displayed when the mouse pointer hovers over the Web server control. (Inherited from WebControl.)
Public property UniqueIDGets the unique, hierarchically qualified identifier for the server control. (Inherited from Control.)
Public property ValidateRequestModeGets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values. (Inherited from Control.)
Public property ValidationGroupGets 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.)
Protected property ViewStateGets 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.)
Protected property ViewStateIgnoresCaseGets a value that indicates whether the StateBag object is case-insensitive. (Inherited from Control.)
Public property ViewStateModeGets or sets the view-state mode of this control. (Inherited from Control.)
Public property VisibleGets or sets a value that indicates whether a server control is rendered as UI on the page. (Inherited from Control.)
Public property WidthGets or sets the width of the Web server control. (Inherited from WebControl.)
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Methods
  NameDescription
Protected method AddAttributesToRenderAdds HTML attributes and styles that need to be rendered to the specified HtmlTextWriter object. (Overrides ListControlAddAttributesToRender(HtmlTextWriter).)
Protected method AddedControlCalled after a child control is added to the Controls collection of the Control object. (Inherited from Control.)
Protected method AddParsedSubObjectNotifies 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.)
Public method ApplyStyleCopies 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.)
Public method ApplyStyleSheetSkinApplies the style properties defined in the page style sheet to the control. (Inherited from Control.)
Protected method BeginRenderTracingBegins design-time tracing of rendering data. (Inherited from Control.)
Protected method BuildProfileTreeInfrastructure. 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.)
Protected method ClearCachedClientIDInfrastructure. Sets the cached ClientID value to . (Inherited from Control.)
Protected method ClearChildControlStateDeletes the control-state information for the server control's child controls. (Inherited from Control.)
Protected method ClearChildStateDeletes the view-state and control-state information for all the server control's child controls. (Inherited from Control.)
Protected method ClearChildViewStateDeletes the view-state information for all the server control's child controls. (Inherited from Control.)
Protected method ClearEffectiveClientIDModeInfrastructure. Sets the ClientIDMode property of the current control instance and of any child controls to Inherit. (Inherited from Control.)
Public method ClearSelectionClears out the list selection and sets the Selected property of all items to false. (Inherited from ListControl.)
Protected method ConfirmInitStateSets the initialized state of the data-bound control. (Inherited from BaseDataBoundControl.)
Public method CopyBaseAttributesCopies 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.)
Protected method CreateChildControlsCalled 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.)
Protected method CreateControlCollectionCreates a collection to store child controls. (Overrides ControlCreateControlCollection.)
Protected method CreateControlStyleCreates 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.)
Protected method CreateDataSourceSelectArgumentsCreates a default DataSourceSelectArguments object used by the data-bound control if no arguments are specified. (Inherited from DataBoundControl.)
Public method DataBindBinds a data source to the invoked server control and all its child controls. (Inherited from BaseDataBoundControl.)
Protected method 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.)
Protected method DataBindChildrenBinds a data source to the server control's child controls. (Inherited from Control.)
Public method DisposeEnables a server control to perform final clean up before it is released from memory. (Inherited from Control.)
Protected method EndRenderTracingEnds design-time tracing of rendering data. (Inherited from Control.)
Protected method EnsureChildControlsDetermines whether the server control contains child controls. If it does not, it creates child controls. (Inherited from Control.)
Protected method EnsureDataBoundCalls the DataBind method if the DataSourceID property is set and the data-bound control is marked to require binding. (Inherited from BaseDataBoundControl.)
Protected method EnsureIDCreates an identifier for controls that do not have an identifier assigned. (Inherited from Control.)
Public method Equals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected method FinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method FindControl(String)Searches the current naming container for a server control with the specified id parameter. (Inherited from Control.)
Protected method FindControl(String, Int32)Infrastructure. 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.)
Public method FocusSets input focus to a control. (Inherited from Control.)
Protected method GetDataRetrieves a DataSourceView object that the data-bound control uses to perform data operations. (Inherited from DataBoundControl.)
Protected method GetDataSourceRetrieves the IDataSource interface that the data-bound control is associated with, if any. (Inherited from DataBoundControl.)
Protected method GetDesignModeStateInfrastructure. Gets design-time data for a control. (Inherited from Control.)
Public method GetHashCodeServes as the default hash function. (Inherited from Object.)
Public method GetRouteUrl(Object)Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
Public method GetRouteUrl(RouteValueDictionary)Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
Public method GetRouteUrl(String, Object)Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
Public method GetRouteUrl(String, RouteValueDictionary)Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
Public method GetTypeGets the Type of the current instance. (Inherited from Object.)
Public method GetUniqueIDRelativeToReturns the prefixed portion of the UniqueID property of the specified control. (Inherited from Control.)
Public method HasControlsDetermines if the server control contains any child controls. (Inherited from Control.)
Protected method HasEventsReturns a value indicating whether events are registered for the control or any child controls. (Inherited from Control.)
Protected method IsLiteralContentInfrastructure. Determines if the server control holds only literal content. (Inherited from Control.)
Protected method LoadControlStateRestores control-state information from a previous page request that was saved by the SaveControlState method. (Inherited from Control.)
Protected method LoadPostDataProcesses postback data for the DropDownList control.
Protected method LoadViewStateLoads the previously saved view state of the DetailsView control. (Inherited from ListControl.)
Protected method MapPathSecureRetrieves the physical path that a virtual path, either absolute or relative, maps to. (Inherited from Control.)
Protected method MarkAsDataBoundSets the state of the control in view state as successfully bound to data. (Inherited from DataBoundControl.)
Protected method MemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public method MergeStyleCopies 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.)
Protected method OnBubbleEventDetermines whether the event for the server control is passed up the page's UI server control hierarchy. (Inherited from Control.)
Protected method OnCreatingModelDataSourceRaises the CreatingModelDataSource event. (Inherited from DataBoundControl.)
Protected method OnDataBindingInfrastructure. Raises the DataBinding event. (Inherited from ListControl.)
Protected method OnDataBoundRaises the DataBound event. (Inherited from BaseDataBoundControl.)
Protected method OnDataPropertyChangedRebinds the data-bound control to its data after one of the base data source identification properties changes. (Inherited from DataBoundControl.)
Protected method OnDataSourceViewChangedRaises the DataSourceViewChanged event. (Inherited from DataBoundControl.)
Protected method OnInitHandles the Init event. (Inherited from BaseDataBoundControl.)
Protected method OnLoadHandles the ControlLoad event. (Inherited from DataBoundControl.)
Protected method OnPagePreLoadSets the initialized state of the data-bound control before the control is loaded. (Inherited from DataBoundControl.)
Protected method OnPreRenderRaises the PreRender event. (Inherited from ListControl.)
Protected method OnSelectedIndexChangedRaises the SelectedIndexChanged event. This allows you to provide a custom handler for the event. (Inherited from ListControl.)
Protected method OnTextChangedRaises the TextChanged event. (Inherited from ListControl.)
Protected method OnUnloadRaises the Unload event. (Inherited from Control.)
Protected method OpenFileGets a Stream used to read a file. (Inherited from Control.)
Protected method PerformDataBindingInfrastructure. Binds the specified data source to the control that is derived from the ListControl class. (Inherited from ListControl.)
Protected method PerformSelectRetrieves data from the associated data source. (Inherited from ListControl.)
Protected method RaiseBubbleEventAssigns any sources of the event and its information to the control's parent. (Inherited from Control.)
Protected method RaisePostDataChangedEventRaises events for the DropDownList control when postback occurs.
Protected method RemovedControlCalled after a child control is removed from the Controls collection of the Control object. (Inherited from Control.)
Protected method RenderRenders the control to the specified HTML writer. (Inherited from WebControl.)
Public method RenderBeginTagRenders the HTML opening tag of the control to the specified writer. This method is used primarily by control developers. (Inherited from WebControl.)
Protected method RenderChildrenOutputs 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.)
Protected method RenderContentsRenders the items in the ListControl control. (Inherited from ListControl.)
Public method 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.)
Protected method RenderControl(HtmlTextWriter, ControlAdapter)Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control.)
Public method RenderEndTagRenders the HTML closing tag of the control into the specified writer. This method is used primarily by control developers. (Inherited from WebControl.)
Protected method ResolveAdapterGets the control adapter responsible for rendering the specified control. (Inherited from Control.)
Public method ResolveClientUrlGets a URL that can be used by the browser. (Inherited from Control.)
Public method ResolveUrlConverts a URL into one that is usable on the requesting client. (Inherited from Control.)
Protected method SaveControlStateSaves any server control state changes that have occurred since the time the page was posted back to the server. (Inherited from Control.)
Protected method SaveViewStateSaves the current view state of the ListControl -derived control and the items it contains. (Inherited from ListControl.)
Protected method SetDesignModeStateSets design-time data for a control. (Inherited from Control.)
Protected method SetPostDataSelectionInfrastructure. Sets the Selected property of a ListItem control after a page is posted. (Inherited from ListControl.)
Public method SetRenderMethodDelegateInfrastructure. Assigns an event handler delegate to render the server control and its content into its parent control. (Inherited from Control.)
Public method 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.)
Public method 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.)
Public method ToStringReturns a string that represents the current object. (Inherited from Object.)
Protected method TrackViewStateMarks the starting point to begin tracking and saving view-state changes to a ListControl -derived control. (Inherited from ListControl.)
Protected method ValidateDataSourceVerifies that the object a data-bound control binds to is one it can work with. (Inherited from DataBoundControl.)
Protected method VerifyMultiSelectAlways throws an HttpException exception because multiple selection is not supported for the DropDownList control. (Overrides ListControlVerifyMultiSelect.)
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Events
  NameDescription
Public event CallingDataMethodsOccurs when data methods are being called. (Inherited from DataBoundControl.)
Public event CreatingModelDataSourceOccurs when the ModelDataSource object is being created. (Inherited from DataBoundControl.)
Public event DataBindingOccurs when the server control binds to a data source. (Inherited from Control.)
Public event DataBoundOccurs after the server control binds to a data source. (Inherited from BaseDataBoundControl.)
Public event DisposedOccurs 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.)
Public event InitOccurs when the server control is initialized, which is the first step in its lifecycle. (Inherited from Control.)
Public event LoadOccurs when the server control is loaded into the Page object. (Inherited from Control.)
Public event PreRenderOccurs after the Control object is loaded but prior to rendering. (Inherited from Control.)
Public event SelectedIndexChangedOccurs when the selection from the list control changes between posts to the server. (Inherited from ListControl.)
Public event TextChangedOccurs when the Text and SelectedValue properties change. (Inherited from ListControl.)
Public event UnloadOccurs when the server control is unloaded from memory. (Inherited from Control.)
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Extension Methods
  NameDescription
Public Extension Method EnablePersistedSelectionEnables selection to be persisted in data controls that support selection and paging. (Defined by DynamicDataExtensions.)
Public Extension Method FindDataSourceControlReturns the data source that is associated with the data control for the specified control. (Defined by DynamicDataExtensions.)
Public Extension Method FindFieldTemplateReturns the field template for the specified column in the specified control's naming container. (Defined by DynamicDataExtensions.)
Public Extension Method FindMetaTableReturns the metatable object for the containing data control. (Defined by DynamicDataExtensions.)
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Explicit Interface Implementations
  NameDescription
Explicit interface implemetation Private method IAttributeAccessorGetAttributeInfrastructure. Gets an attribute of the Web control with the specified name. (Inherited from WebControl.)
Explicit interface implemetation Private method IAttributeAccessorSetAttributeSets an attribute of the Web control to the specified name and value. (Inherited from WebControl.)
Explicit interface implemetation Private property IControlBuilderAccessorControlBuilderFor a description of this member, see IControlBuilderAccessorControlBuilder. (Inherited from Control.)
Explicit interface implemetation Private method IControlDesignerAccessorGetDesignModeStateFor a description of this member, see IControlDesignerAccessorGetDesignModeState. (Inherited from Control.)
Explicit interface implemetation Private method IControlDesignerAccessorSetDesignModeStateFor a description of this member, see IControlDesignerAccessorSetDesignModeState. (Inherited from Control.)
Explicit interface implemetation Private method IControlDesignerAccessorSetOwnerControlInfrastructure. For a description of this member, see IControlDesignerAccessorSetOwnerControl. (Inherited from Control.)
Explicit interface implemetation Private property IControlDesignerAccessorUserDataFor a description of this member, see IControlDesignerAccessorUserData. (Inherited from Control.)
Explicit interface implemetation Private property IDataBindingsAccessorDataBindingsFor a description of this member, see IDataBindingsAccessorDataBindings. (Inherited from Control.)
Explicit interface implemetation Private property IDataBindingsAccessorHasDataBindingsFor a description of this member, see IDataBindingsAccessorHasDataBindings. (Inherited from Control.)
Explicit interface implemetation Private property IExpressionsAccessorExpressionsFor a description of this member, see IExpressionsAccessorExpressions. (Inherited from Control.)
Explicit interface implemetation Private property IExpressionsAccessorHasExpressionsFor a description of this member, see IExpressionsAccessorHasExpressions. (Inherited from Control.)
Explicit interface implemetation Private method IParserAccessorAddParsedSubObjectFor a description of this member, see IParserAccessorAddParsedSubObject. (Inherited from Control.)
Explicit interface implemetation Private method IPostBackDataHandlerLoadPostDataInfrastructure. Processes posted data for the DropDownList control.
Explicit interface implemetation Private method IPostBackDataHandlerRaisePostDataChangedEventInfrastructure. Raises events for the DropDownList control on postback.
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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 BorderColor, BorderStyle, and BorderWidth 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 SelectedIndex 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="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>
 
<%@ 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>
 

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

<%@ 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>
 
<%@ 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>
 
Version Information

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
Platforms

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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.