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Button Class

Displays a push button control on the Web page.

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

public class Button : WebControl, IButtonControl, 
	IPostBackEventHandler
<asp:Button />

The Button type exposes the following members.

  NameDescription
Public methodButtonInitializes a new instance of the Button class.
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  NameDescription
Public propertyAccessKeyGets or sets the access key that allows you to quickly navigate to the Web server control. (Inherited from WebControl.)
Protected propertyAdapterGets the browser-specific adapter for the control. (Inherited from Control.)
Public propertyAppRelativeTemplateSourceDirectoryGets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. (Inherited from Control.)
Public propertyAttributesGets the collection of arbitrary attributes (for rendering only) that do not correspond to properties on the control. (Inherited from WebControl.)
Public propertyBackColorGets or sets the background color of the Web server control. (Inherited from WebControl.)
Public propertyBindingContainerInfrastructure. Gets the control that contains this control's data binding. (Inherited from Control.)
Public propertyBorderColorGets or sets the border color of the Web control. (Inherited from WebControl.)
Public propertyBorderStyleGets or sets the border style of the Web server control. (Inherited from WebControl.)
Public propertyBorderWidthGets or sets the border width of the Web server control. (Inherited from WebControl.)
Public propertyCausesValidationGets or sets a value indicating whether validation is performed when the Button control is clicked.
Protected propertyChildControlsCreatedGets a value that indicates whether the server control's child controls have been created. (Inherited from Control.)
Public propertyClientIDGets the control ID for HTML markup that is generated by ASP.NET. (Inherited from Control.)
Public propertyClientIDModeGets or sets the algorithm that is used to generate the value of the ClientID property. (Inherited from Control.)
Protected propertyClientIDSeparatorGets a character value representing the separator character used in the ClientID property. (Inherited from Control.)
Public propertyCommandArgumentGets or sets an optional parameter passed to the Command event along with the associated CommandName.
Public propertyCommandNameGets or sets the command name associated with the Button control that is passed to the Command event.
Protected propertyContextGets the HttpContext object associated with the server control for the current Web request. (Inherited from Control.)
Public propertyControlsGets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy. (Inherited from Control.)
Public propertyControlStyleGets the style of the Web server control. This property is used primarily by control developers. (Inherited from WebControl.)
Public propertyControlStyleCreatedGets 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 propertyCssClassGets or sets the Cascading Style Sheet (CSS) class rendered by the Web server control on the client. (Inherited from WebControl.)
Public propertyDataItemContainerGets a reference to the naming container if the naming container implements IDataItemContainer. (Inherited from Control.)
Public propertyDataKeysContainerGets a reference to the naming container if the naming container implements IDataKeysControl. (Inherited from Control.)
Protected propertyDesignModeGets a value indicating whether a control is being used on a design surface. (Inherited from Control.)
Public propertyEnabledGets or sets a value indicating whether the Web server control is enabled. (Inherited from WebControl.)
Public propertyEnableThemingGets or sets a value indicating whether themes apply to this control. (Inherited from WebControl.)
Public propertyEnableViewStateGets 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 propertyEventsGets a list of event handler delegates for the control. This property is read-only. (Inherited from Control.)
Public propertyFontGets the font properties associated with the Web server control. (Inherited from WebControl.)
Public propertyForeColorGets or sets the foreground color (typically the color of the text) of the Web server control. (Inherited from WebControl.)
Public propertyHasAttributesGets a value indicating whether the control has attributes set. (Inherited from WebControl.)
Protected propertyHasChildViewStateGets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control.)
Public propertyHeightGets or sets the height of the Web server control. (Inherited from WebControl.)
Public propertyIDGets or sets the programmatic identifier assigned to the server control. (Inherited from Control.)
Protected propertyIdSeparatorInfrastructure. Gets the character used to separate control identifiers. (Inherited from Control.)
Protected propertyIsChildControlStateClearedGets a value indicating whether controls contained within this control have control state. (Inherited from Control.)
Protected propertyIsEnabledGets a value indicating whether the control is enabled. (Inherited from WebControl.)
Protected propertyIsTrackingViewStateGets a value that indicates whether the server control is saving changes to its view state. (Inherited from Control.)
Protected propertyIsViewStateEnabledGets a value indicating whether view state is enabled for this control. (Inherited from Control.)
Protected propertyLoadViewStateByIDGets a value indicating whether the control participates in loading its view state by ID instead of index. (Inherited from Control.)
Public propertyNamingContainerGets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same Control.ID property value. (Inherited from Control.)
Public propertyOnClientClickGets or sets the client-side script that executes when a Button control's Click event is raised.
Public propertyPageGets a reference to the Page instance that contains the server control. (Inherited from Control.)
Public propertyParentGets a reference to the server control's parent control in the page control hierarchy. (Inherited from Control.)
Public propertyPostBackUrlGets or sets the URL of the page to post to from the current page when the Button control is clicked.
Public propertyRenderingCompatibilityGets a value that specifies the ASP.NET version that rendered HTML will be compatible with. (Inherited from Control.)
Public propertySiteGets information about the container that hosts the current control when rendered on a design surface. (Inherited from Control.)
Public propertySkinIDGets or sets the skin to apply to the control. (Inherited from WebControl.)
Public propertyStyleGets 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 propertySupportsDisabledAttributeGets a value that indicates whether the control should set the disabled attribute of the rendered HTML element to "disabled" when the control's IsEnabled property is false. (Inherited from WebControl.)
Public propertyTabIndexGets or sets the tab index of the Web server control. (Inherited from WebControl.)
Protected propertyTagKeyGets the HtmlTextWriterTag value that corresponds to this Web server control. This property is used primarily by control developers. (Inherited from WebControl.)
Protected propertyTagNameGets the name of the control tag. This property is used primarily by control developers. (Inherited from WebControl.)
Public propertyTemplateControlGets or sets a reference to the template that contains this control. (Inherited from Control.)
Public propertyTemplateSourceDirectoryGets the virtual directory of the Page or UserControl that contains the current server control. (Inherited from Control.)
Public propertyTextGets or sets the text caption displayed in the Button control.
Public propertyToolTipGets or sets the text displayed when the mouse pointer hovers over the Web server control. (Inherited from WebControl.)
Public propertyUniqueIDGets the unique, hierarchically qualified identifier for the server control. (Inherited from Control.)
Public propertyUseSubmitBehaviorGets or sets a value indicating whether the Button control uses the client browser's submit mechanism or the ASP.NET postback mechanism.
Public propertyValidateRequestModeGets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values. (Inherited from Control.)
Public propertyValidationGroupGets or sets the group of controls for which the Button control causes validation when it posts back to the server.
Protected propertyViewStateGets 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 propertyViewStateIgnoresCaseGets a value that indicates whether the StateBag object is case-insensitive. (Inherited from Control.)
Public propertyViewStateModeGets or sets the view-state mode of this control. (Inherited from Control.)
Public propertyVisibleGets or sets a value that indicates whether a server control is rendered as UI on the page. (Inherited from Control.)
Public propertyWidthGets or sets the width of the Web server control. (Inherited from WebControl.)
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  NameDescription
Protected methodAddAttributesToRenderInfrastructure. Adds the attributes of the Button control to the output stream for rendering on the client. (Overrides WebControl.AddAttributesToRender(HtmlTextWriter).)
Protected methodAddedControlCalled after a child control is added to the Controls collection of the Control object. (Inherited from Control.)
Protected methodAddParsedSubObjectNotifies 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 methodApplyStyleCopies 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 methodApplyStyleSheetSkinApplies the style properties defined in the page style sheet to the control. (Inherited from Control.)
Protected methodBeginRenderTracingBegins design-time tracing of rendering data. (Inherited from Control.)
Protected methodBuildProfileTreeInfrastructure. 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 methodClearCachedClientIDInfrastructure. Sets the cached ClientID value to null. (Inherited from Control.)
Protected methodClearChildControlStateDeletes the control-state information for the server control's child controls. (Inherited from Control.)
Protected methodClearChildStateDeletes the view-state and control-state information for all the server control's child controls. (Inherited from Control.)
Protected methodClearChildViewStateDeletes the view-state information for all the server control's child controls. (Inherited from Control.)
Protected methodClearEffectiveClientIDModeInfrastructure. Sets the ClientIDMode property of the current control instance and of any child controls to Inherit. (Inherited from Control.)
Public methodCopyBaseAttributesCopies 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 methodCreateChildControlsCalled 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 methodCreateControlCollectionCreates a new ControlCollection object to hold the child controls (both literal and server) of the server control. (Inherited from Control.)
Protected methodCreateControlStyleCreates 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.)
Public methodDataBind()Binds a data source to the invoked server control and all its child controls. (Inherited from Control.)
Protected methodDataBind(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 methodDataBindChildrenBinds a data source to the server control's child controls. (Inherited from Control.)
Public methodDisposeEnables a server control to perform final clean up before it is released from memory. (Inherited from Control.)
Protected methodEndRenderTracingEnds design-time tracing of rendering data. (Inherited from Control.)
Protected methodEnsureChildControlsDetermines whether the server control contains child controls. If it does not, it creates child controls. (Inherited from Control.)
Protected methodEnsureIDCreates an identifier for controls that do not have an identifier assigned. (Inherited from Control.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodFindControl(String)Searches the current naming container for a server control with the specified id parameter. (Inherited from Control.)
Protected methodFindControl(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 methodFocusSets input focus to a control. (Inherited from Control.)
Protected methodGetDesignModeStateInfrastructure. Gets design-time data for a control. (Inherited from Control.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Protected methodGetPostBackOptionsCreates a PostBackOptions object that represents the Button control's postback behavior.
Public methodGetRouteUrl(Object)Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
Public methodGetRouteUrl(RouteValueDictionary)Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
Public methodGetRouteUrl(String, Object)Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
Public methodGetRouteUrl(String, RouteValueDictionary)Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetUniqueIDRelativeToReturns the prefixed portion of the UniqueID property of the specified control. (Inherited from Control.)
Public methodHasControlsDetermines if the server control contains any child controls. (Inherited from Control.)
Protected methodHasEventsReturns a value indicating whether events are registered for the control or any child controls. (Inherited from Control.)
Protected methodIsLiteralContentInfrastructure. Determines if the server control holds only literal content. (Inherited from Control.)
Protected methodLoadControlStateRestores control-state information from a previous page request that was saved by the SaveControlState method. (Inherited from Control.)
Protected methodLoadViewStateRestores view-state information from a previous request that was saved with the SaveViewState method. (Inherited from WebControl.)
Protected methodMapPathSecureRetrieves the physical path that a virtual path, either absolute or relative, maps to. (Inherited from Control.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodMergeStyleCopies 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 methodOnBubbleEventDetermines whether the event for the server control is passed up the page's UI server control hierarchy. (Inherited from Control.)
Protected methodOnClickRaises the Click event of the Button control.
Protected methodOnCommandRaises the Command event of the Button control.
Protected methodOnDataBindingRaises the DataBinding event. (Inherited from Control.)
Protected methodOnInitRaises the Init event. (Inherited from Control.)
Protected methodOnLoadRaises the Load event. (Inherited from Control.)
Protected methodOnPreRenderDetermines whether the button has been clicked prior to rendering on the client. (Overrides Control.OnPreRender(EventArgs).)
Protected methodOnUnloadRaises the Unload event. (Inherited from Control.)
Protected methodOpenFileGets a Stream used to read a file. (Inherited from Control.)
Protected methodRaiseBubbleEventAssigns any sources of the event and its information to the control's parent. (Inherited from Control.)
Protected methodRaisePostBackEventRaises events for the Button control when it posts back to the server.
Protected methodRemovedControlCalled after a child control is removed from the Controls collection of the Control object. (Inherited from Control.)
Protected methodRenderRenders the control to the specified HTML writer. (Inherited from WebControl.)
Public methodRenderBeginTagRenders the HTML opening tag of the control to the specified writer. This method is used primarily by control developers. (Inherited from WebControl.)
Protected methodRenderChildrenOutputs 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 methodRenderContentsRenders the contents of the control to the specified writer. (Overrides WebControl.RenderContents(HtmlTextWriter).)
Public methodRenderControl(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 methodRenderControl(HtmlTextWriter, ControlAdapter)Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control.)
Public methodRenderEndTagRenders the HTML closing tag of the control into the specified writer. This method is used primarily by control developers. (Inherited from WebControl.)
Protected methodResolveAdapterGets the control adapter responsible for rendering the specified control. (Inherited from Control.)
Public methodResolveClientUrlGets a URL that can be used by the browser. (Inherited from Control.)
Public methodResolveUrlConverts a URL into one that is usable on the requesting client. (Inherited from Control.)
Protected methodSaveControlStateSaves any server control state changes that have occurred since the time the page was posted back to the server. (Inherited from Control.)
Protected methodSaveViewStateSaves any state that was modified after the TrackViewState method was invoked. (Inherited from WebControl.)
Protected methodSetDesignModeStateSets design-time data for a control. (Inherited from Control.)
Public methodSetRenderMethodDelegateInfrastructure. Assigns an event handler delegate to render the server control and its content into its parent control. (Inherited from Control.)
Public methodSetTraceData(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 methodSetTraceData(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 methodToStringReturns a string that represents the current object. (Inherited from Object.)
Protected methodTrackViewStateCauses the control to track changes to its view state so they can be stored in the object's ViewState property. (Inherited from WebControl.)
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  NameDescription
Public eventClickOccurs when the Button control is clicked.
Public eventCommandOccurs when the Button control is clicked.
Public eventDataBindingOccurs when the server control binds to a data source. (Inherited from Control.)
Public eventDisposedOccurs 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 eventInitOccurs when the server control is initialized, which is the first step in its lifecycle. (Inherited from Control.)
Public eventLoadOccurs when the server control is loaded into the Page object. (Inherited from Control.)
Public eventPreRenderOccurs after the Control object is loaded but prior to rendering. (Inherited from Control.)
Public eventUnloadOccurs when the server control is unloaded from memory. (Inherited from Control.)
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  NameDescription
Public Extension MethodFindDataSourceControlReturns the data source that is associated with the data control for the specified control. (Defined by DynamicDataExtensions.)
Public Extension MethodFindFieldTemplateReturns the field template for the specified column in the specified control's naming container. (Defined by DynamicDataExtensions.)
Public Extension MethodFindMetaTableReturns the metatable object for the containing data control. (Defined by DynamicDataExtensions.)
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  NameDescription
Explicit interface implemetationPrivate methodIAttributeAccessor.GetAttributeInfrastructure. Gets an attribute of the Web control with the specified name. (Inherited from WebControl.)
Explicit interface implemetationPrivate methodIAttributeAccessor.SetAttributeSets an attribute of the Web control to the specified name and value. (Inherited from WebControl.)
Explicit interface implemetationPrivate propertyIControlBuilderAccessor.ControlBuilderFor a description of this member, see IControlBuilderAccessor.ControlBuilder. (Inherited from Control.)
Explicit interface implemetationPrivate methodIControlDesignerAccessor.GetDesignModeStateFor a description of this member, see IControlDesignerAccessor.GetDesignModeState. (Inherited from Control.)
Explicit interface implemetationPrivate methodIControlDesignerAccessor.SetDesignModeStateFor a description of this member, see IControlDesignerAccessor.SetDesignModeState. (Inherited from Control.)
Explicit interface implemetationPrivate methodIControlDesignerAccessor.SetOwnerControlInfrastructure. For a description of this member, see IControlDesignerAccessor.SetOwnerControl. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIControlDesignerAccessor.UserDataFor a description of this member, see IControlDesignerAccessor.UserData. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIDataBindingsAccessor.DataBindingsFor a description of this member, see IDataBindingsAccessor.DataBindings. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIDataBindingsAccessor.HasDataBindingsFor a description of this member, see IDataBindingsAccessor.HasDataBindings. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIExpressionsAccessor.ExpressionsFor a description of this member, see IExpressionsAccessor.Expressions. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIExpressionsAccessor.HasExpressionsFor a description of this member, see IExpressionsAccessor.HasExpressions. (Inherited from Control.)
Explicit interface implemetationPrivate methodIParserAccessor.AddParsedSubObjectFor a description of this member, see IParserAccessor.AddParsedSubObject. (Inherited from Control.)
Explicit interface implemetationPrivate methodIPostBackEventHandler.RaisePostBackEventRaises events for the Button control when it posts back to the server.
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In this topic:

Introduction

Use the Button control to create a push button on the Web page that lets users to post a page to the server. The control triggers an event in server code that you can handle to respond to the postback. It can also raise an event in client script that you can handle before the page is posted or that can run and then cancel submission of the page.

NoteNote

ASP.NET includes several kinds of button controls, each of which appears differently on Web pages. They are the Button control, which renders as a push button; the LinkButton control, which renders as a link; and the ImageButton control, which renders as an image; and the ImageMap control, which lets you create a graphic that has hotspots that users can click. By default, all button controls submit the page when clicked. You can also use the HtmlButton and HtmlInputButton controls to create buttons on the page that are programmable in server code. For details about the differences between HTML and Web server controls, see ASP.NET Web Server Controls Overview.

By default, a Button control is a Submit button. A Submit button does not have a command name (specified by the CommandName property) associated with the button and simply posts the Web page back to the server. You can provide an event handler for the Click event to programmatically control the actions performed when the Submit button is clicked.

A Command button has a command name associated with the button, such as Sort, by setting the CommandName property. This allows you to create multiple Button controls on a Web page and programmatically determine which Button control is clicked. You can also use the CommandArgument property with a command button to provide additional information about the command to perform, such as Ascending. You can provide an event handler for the Command event to programmatically control the actions performed when the Command button is clicked.

Button Postback Behavior and Server Events

When a user clicks any Web server control button, the page is sent to the server. This causes the Web page to be processed and any pending events to be raised in server-based code. When all page and control processing has finished, the page renders itself to the browser again.

The buttons can raise their own Click events or Command event, which you can handle by using server-based code. This is different than events in traditional HTML pages or in client-based Web applications, where a button's onclick event is handled by using JavaScript that runs in the client. For more information, see ASP.NET Web Forms Server Control Event Model.

When users click a button control, the page is posted back to the server. By default, the page is posted back to itself,

You can configure buttons to post the current page to another page. This can be useful for creating multi-page forms. For details, see Cross-Page Posting in ASP.NET Web Forms.

Handling Button Events in Client Script

Button controls can raise both server events and client events. Server events occur after postback, and they are handled in the server-side code that you write for the page. Client events are handled in client script, typically ECMAScript (JavaScript), and are raised before the page is submitted. By adding client-side events to ASP.NET button controls, you can perform tasks such as displaying confirmation dialog boxes before submitting the page, and potentially cancel the submission. For details, see Client Script in ASP.NET Web Pages and How to: Respond to Button Web Server Control Events in Client Script.

You might also want the Button control to also use client script to perform the postback (instead of simply performing an HTTP POST operation). This can be useful if you want to programmatically manipulate the postback, such as attaching it to other elements on the page. You can set the Button control's UseSubmitBehavior property to true to cause the Button control to use client-script based postback.

Button Controls and Validation

If a page contains ASP.NET validator controls, by default, clicking a button control causes the validator control to perform its check. If client-side validation is enabled for a validator control, the page is not submitted if a validation check has failed.

The following table describes the properties supported by button controls that enable you to control the validation process more precisely.

Property

Description

CausesValidation

Specifies whether clicking the button also performs a validation check. Set this property to false to prevent a validation check.

ValidationGroup

Enables you to specify which validators on the page are called when the button is clicked. If no validation groups are established, a button click calls all of the validators that are on the page.

For more information, see Validating User Input in ASP.NET Web Pages.

Buttons in Data Controls

Button Web server controls are often used in data controls, such as in the DataList, GridView, and Repeater list controls. In those cases, you typically do not respond directly to the button click event. Instead, a button in a data control raises an event that is specific to the data control. For example, in the DataList control, a button might raise the DataList control's ItemCommand event instead of raising the Button control's Click event.

Because data-bound list controls can contain many buttons, you can set the button's CommandArgument property to specify a value to pass as part of the event. You can then test for this argument to see which button was clicked.

Binding Data to the Controls

You can bind the button Web server controls to a data source in order to control their property settings dynamically. For example, you can set a button's Text property by using data binding.

Using Buttons with UpdatePanel Controls

Partial-page rendering makes it possible to refresh portions of a page without a postback. UpdatePanel controls enable you to mark parts of the page that participate in partial-page rendering. By default, the behavior of controls inside an UpdatePanel control, including Button controls, is to perform an asynchronous postback instead of a postback. This refreshes only the contents of the UpdatePanel control from which the postback originates.

In addition to the scenario of a Button control that is inside an UpdatePanel control, you can use Button controls with UpdatePanel controls in the following scenarios:

  • Defining a Button control that is outside an UpdatePanel control as an AsyncPostBackTrigger control for that panel. When the button is clicked, it performs an asynchronous postback and refreshes the contents of the panel.

  • Defining a Button control that is inside an UpdatePanel control as a PostBackTrigger for the panel. When the button is clicked, it performs a postback even though it is inside an UpdatePanel control.

For more information about partial-page rendering and using UpdatePanel controls, see UpdatePanel Control Overview and Partial-Page Rendering Overview.

Declarative Syntax

<asp:Button
    AccessKey="string"
    BackColor="color name|#dddddd"
    BorderColor="color name|#dddddd"
    BorderStyle="NotSet|None|Dotted|Dashed|Solid|Double|Groove|Ridge|
        Inset|Outset"
    BorderWidth="size"
    CausesValidation="True|False"
    CommandArgument="string"
    CommandName="string"
    CssClass="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"
    OnClick="Click event handler"
    OnClientClick="string"
    OnCommand="Command event handler"
    OnDataBinding="DataBinding event handler"
    OnDisposed="Disposed event handler"
    OnInit="Init event handler"
    OnLoad="Load event handler"
    OnPreRender="PreRender event handler"
    OnUnload="Unload event handler"
    PostBackUrl="uri"
    runat="server"
    SkinID="string"
    Style="string"
    TabIndex="integer"
    Text="string"
    ToolTip="string"
    UseSubmitBehavior="True|False"
    ValidationGroup="string"
    Visible="True|False"
    Width="size"
/>
TopicLocation
How to: Respond to Button Web Server Control Events in Client ScriptBuilding ASP .NET Web Applications
How to: Connect Multiple Events to a Single Event Handler in ASP.NET Web PagesBuilding ASP .NET Web Applications
How to: Add Button Web Server Controls to a Web Forms PageBuilding ASP .NET Web Applications
Walkthrough: Creating a Basic Control Designer for an ASP.NET Web Server ControlAuthoring ASP.NET Controls
How to: Respond to Button Web Server Control Events in Client ScriptBuilding ASP .NET Web Applications
How to: Connect Multiple Events to a Single Event Handler in ASP.NET Web PagesBuilding ASP .NET Web Applications
How to: Determine which Web Server Control Raised an EventBuilding ASP .NET Web Applications
How to: Add Button Web Server Controls to a Web Forms PageBuilding ASP .NET Web Applications
How to: Set Focus on ASP.NET Web Server ControlsBuilding ASP .NET Web Applications
How to: Add PlaceHolder Web Server Controls to a Web Forms PageBuilding ASP .NET Web Applications
How to: Respond to Button Web Server Control EventsBuilding ASP .NET Web Applications
How to: Respond to Button Events in Data-Bound ControlsBuilding ASP .NET Web Applications
How to: Respond to Button Events in DataList, Repeater, or GridView ItemsBuilding ASP .NET Web Applications
Walkthrough: Creating Reusable Elements with ASP.NET User ControlsBuilding ASP .NET Web Applications in Visual Studio
Walkthrough: Creating and Using ASP.NET Master Pages in Visual Web DeveloperBuilding ASP .NET Web Applications in Visual Studio
Walkthrough: Validating User Input in a Web Forms PageBuilding ASP .NET Web Applications in Visual Studio
Walkthrough: Data Binding to a Custom Business ObjectBuilding ASP .NET Web Applications in Visual Studio
How to: Add Button Web Server Controls to a Web Forms Page (Visual Studio)Building ASP .NET Web Applications in Visual Studio
How to: Add Button Web Server Controls to a Web Forms PageBuilding ASP .NET Web Applications in Visual Studio
Walkthrough: Customizing a Web Site Using Themes in Visual StudioBuilding ASP .NET Web Applications in Visual Studio
Walkthrough: Creating a Basic Web Page in Visual Web DeveloperBuilding ASP .NET Web Applications in Visual Studio
How to: Create Event Handlers in ASP.NET Web Pages (Visual Studio)Building ASP .NET Web Applications in Visual Studio
Walkthrough: Working with Cascading Style Sheet Styles in Visual Web DeveloperBuilding ASP .NET Web Applications in Visual Studio
How to: Respond to Button Events in DataList, Repeater, or GridView ItemsBuilding ASP .NET Web Applications
How to: Respond to Button Events in Data-Bound ControlsBuilding ASP .NET Web Applications
How to: Respond to Button Web Server Control EventsBuilding ASP .NET Web Applications
How to: Add PlaceHolder Web Server Controls to a Web Forms PageBuilding ASP .NET Web Applications
Walkthrough: Creating a Basic Control Designer for an ASP.NET Web Server ControlAuthoring ASP.NET Controls
How to: Set Focus on ASP.NET Web Server ControlsBuilding ASP .NET Web Applications
How to: Determine which Web Server Control Raised an EventBuilding ASP .NET Web Applications

The following code example demonstrates how to create a Submit Button control that posts the Web page content back to the server.

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>Button Example</title>
<script language="C#" runat="server">

      void SubmitBtn_Click(Object sender, EventArgs e) 
      {
         Message.Text="Hello World!!";
      }

   </script>
</head>
<body>
   <form id="form1" runat="server">

      <h3>Button Example</h3>

      Click on the submit button.<br /><br />

      <asp:Button id="Button1"
           Text="Submit"
           OnClick="SubmitBtn_Click" 
           runat="server"/>

      <br />

      <asp:label id="Message" runat="server"/>

   </form>
</body>
</html>

The following code example demonstrates how to create a Command Button control that sorts a list.

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Button CommandName Example</title>
<script runat="server">

      void CommandBtn_Click(Object sender, CommandEventArgs e) 
      {

         switch(e.CommandName)
         {

            case "Sort":

               // Call the method to sort the list.
               Sort_List((String)e.CommandArgument);
               break;

            case "Submit":

               // Display a message for the Submit button being clicked.
               Message.Text = "You clicked the Submit button";

               // Test whether the command argument is an empty string ("").
               if((String)e.CommandArgument == "")
               {
                  // End the message.
                  Message.Text += ".";
               }
               else
               {
                  // Display an error message for the command argument. 
                  Message.Text += ", however the command argument is not recogized.";
               }                
               break;

            default:

               // The command name is not recognized. Display an error message.
               Message.Text = "Command name not recogized.";
               break; 

         }

      }

      void Sort_List(string commandArgument)
      {

         switch(commandArgument)
         {

            case "Ascending":

               // Insert code to sort the list in ascending order here.
               Message.Text = "You clicked the Sort Ascending button.";
               break;

            case "Descending":

               // Insert code to sort the list in descending order here.
               Message.Text = "You clicked the Sort Descending button.";
               break;

            default:

               // The command argument is not recognized. Display an error message.
               Message.Text = "Command argument not recogized.";
               break;

         }

      }

   </script>

</head>

<body>

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

      <h3>Button CommandName Example</h3>

      Click on one of the command buttons.

      <br /><br />

      <asp:Button id="Button1"
           Text="Sort Ascending"
           CommandName="Sort"
           CommandArgument="Ascending"
           OnCommand="CommandBtn_Click" 
           runat="server"/>

      &nbsp;

      <asp:Button id="Button2"
           Text="Sort Descending"
           CommandName="Sort"
           CommandArgument="Descending"
           OnCommand="CommandBtn_Click" 
           runat="server"/>

      <br /><br />

      <asp:Button id="Button3"
           Text="Submit"
           CommandName="Submit"
           OnCommand="CommandBtn_Click" 
           runat="server"/>

      &nbsp;

      <asp:Button id="Button4"
           Text="Unknown Command Name"
           CommandName="UnknownName"
           CommandArgument="UnknownArgument"
           OnCommand="CommandBtn_Click" 
           runat="server"/>

      &nbsp;

      <asp:Button id="Button5"
           Text="Submit Unknown Command Argument"
           CommandName="Submit"
           CommandArgument="UnknownArgument"
           OnCommand="CommandBtn_Click" 
           runat="server"/>

      <br /><br />

      <asp:Label id="Message" runat="server"/>

   </form>

</body>
</html>

.NET Framework

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

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.

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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