Documentation for: ASP.NET Ajax Version 1.0

This documentation is for a previous version. For the current released version, see the ASP.NET Ajax documentation on MSDN.

 

 

 

 

 

 

 

UpdatePanel Class

Enables sections of a page to be partially rendered without a postback.

Syntax

CSharp

[DesignerAttribute("System.Web.UI.Design.UpdatePanelDesigner, System.Web.Extensions.Design, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35")]
[DefaultPropertyAttribute("Triggers")]
[ParseChildrenAttribute(true)]
[PersistChildrenAttribute(false)]
[AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public class UpdatePanel : Control

VisualBasic

<DesignerAttribute("System.Web.UI.Design.UpdatePanelDesigner, System.Web.Extensions.Design, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35")> _
<DefaultPropertyAttribute("Triggers")> _
<ParseChildrenAttribute(True)> _
<PersistChildrenAttribute(False)> _
<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public Class UpdatePanel _
	Inherits Control

ManagedCPlusPlus

[DesignerAttribute(L"System.Web.UI.Design.UpdatePanelDesigner, System.Web.Extensions.Design, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35")]
[DefaultPropertyAttribute(L"Triggers")]
[ParseChildrenAttribute(true)]
[PersistChildrenAttribute(false)]
[AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction::InheritanceDemand, Level = AspNetHostingPermissionLevel::Minimal)]
public ref class UpdatePanel : public Control

JSharp

/** @attribute DesignerAttribute("System.Web.UI.Design.UpdatePanelDesigner, System.Web.Extensions.Design, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35") */
/** @attribute DefaultPropertyAttribute("Triggers") */
/** @attribute ParseChildrenAttribute(true) */
/** @attribute PersistChildrenAttribute(false) */
/** @attribute AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal) */
/** @attribute AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal) */
public class UpdatePanel extends Control

Members

IconMemberDescription
UpdatePanelNew()Initializes a new instance of the UpdatePanel class.
AdapterGets the browser-specific adapter for the control. (Inherited from Control.)
AddedControl(Control, Int32)Called after a child control is added to the Controls collection of the Control object. (Inherited from Control.)
AddParsedSubObject(Object)Notifies the server control that an element, either XML or HTML, was parsed, and adds the element to the server control's ControlCollection object. (Inherited from Control.)
ApplyStyleSheetSkin(Page)Applies the style properties defined in the page style sheet to the control. (Inherited from Control.)
AppRelativeTemplateSourceDirectoryGets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. (Inherited from Control.)
BindingContainerGets the control that contains this control's data binding. (Inherited from Control.)
BuildProfileTree(String, Boolean)Gathers information about the server control and delivers it to the Trace property to be displayed when tracing is enabled for the page. (Inherited from Control.)
ChildControlsCreatedGets a value that indicates whether the server control's child controls have been created. (Inherited from Control.)
ChildrenAsTriggersGets or sets a value that indicates whether postbacks from immediate child controls of an UpdatePanel control update the panel's content.
ClearChildControlState()Deletes the control-state information for the server control's child controls. (Inherited from Control.)
ClearChildState()Deletes the view-state and control-state information for all the server control's child controls. (Inherited from Control.)
ClearChildViewState()Deletes the view-state information for all the server control's child controls. (Inherited from Control.)
ClientIDGets the server control identifier generated by ASP.NET. (Inherited from Control.)
ClientIDSeparatorGets a character value representing the separator character used in the ClientID property. (Inherited from Control.)
ContentTemplateGets or sets the template that defines the content of the UpdatePanel control.
ContentTemplateContainerGets a control object to which you can programmatically add child controls.
ContextGets the HttpContext object associated with the server control for the current Web request. (Inherited from Control.)
ControlsGets the ControlCollection object that contains the child controls for the UpdatePanel control. (Overrides Control.Controls.)
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.)
CreateContentTemplateContainer()Creates a Control object that acts as a container for child controls that define the UpdatePanel control's content.
CreateControlCollection()Returns the collection of all controls that are contained in the UpdatePanel control. (Overrides Control.CreateControlCollection().)
DataBind()Binds a data source to the invoked server control and all its child controls. (Inherited from Control.)
DataBind(Boolean)Binds a data source to the invoked server control and all its child controls with an option to raise the DataBinding event. (Inherited from Control.)
DataBindChildren()Binds a data source to the server control's child controls. (Inherited from Control.)
DataBindingOccurs when the server control binds to a data source. (Inherited from Control.)
DesignModeGets a value indicating whether a control is being used on a design surface. (Inherited from Control.)
Dispose()Enables a server control to perform final clean up before it is released from memory. (Inherited from Control.)
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.)
EnableThemingGets or sets a value indicating whether themes apply to this control. (Inherited from Control.)
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.)
EnsureChildControls()Determines whether the server control contains child controls. If it does not, it creates child controls. (Inherited from Control.)
EnsureID()Creates an identifier for controls that do not have an identifier assigned. (Inherited from Control.)
Equals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
EventsGets a list of event handler delegates for the control. This property is read-only. (Inherited from Control.)
Finalize()Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
FindControl(String)Searches the current naming container for a server control with the specified id parameter. (Inherited from Control.)
FindControl(String, Int32)Searches the current naming container for a server control with the specified id and an integer, specified in the pathOffset parameter, which aids in the search. You should not override this version of the method. (Inherited from Control.)
Focus()Sets input focus to a control. (Inherited from Control.)
GetDesignModeState()Gets design-time data for a control. (Inherited from Control.)
GetHashCode()Serves as a hash function for a particular type. (Inherited from Object.)
GetType()Gets the Type of the current instance. (Inherited from Object.)
HasChildViewStateGets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control.)
HasControls()Determines if the server control contains any child controls. (Inherited from Control.)
HasEvents()Returns a value indicating whether events are registered for the control or any child controls. (Inherited from Control.)
IDGets or sets the programmatic identifier assigned to the server control. (Inherited from Control.)
IdSeparatorGets the character used to separate control identifiers. (Inherited from Control.)
InitOccurs when the server control is initialized, which is the first step in its lifecycle. (Inherited from Control.)
Initialize()Initializes the UpdatePanel control trigger collection if partial-page rendering is enabled.
IsChildControlStateClearedGets a value indicating whether controls contained within this control have control state. (Inherited from Control.)
IsInPartialRenderingGets a value that indicates whether the UpdatePanel control is being updated as a result of an asynchronous postback.
IsLiteralContent()Determines if the server control holds only literal content. (Inherited from Control.)
IsTrackingViewStateGets a value that indicates whether the server control is saving changes to its view state. (Inherited from Control.)
IsViewStateEnabledGets a value indicating whether view state is enabled for this control. (Inherited from Control.)
LoadOccurs when the server control is loaded into the Page object. (Inherited from Control.)
LoadControlState(Object)Restores control-state information from a previous page request that was saved by the SaveControlState() method. (Inherited from Control.)
LoadViewState(Object)Restores view-state information from a previous page request that was saved by the SaveViewState() method. (Inherited from Control.)
LoadViewStateByIDGets a value indicating whether the control participates in loading its view state by ID instead of index. (Inherited from Control.)
MapPathSecure(String)Retrieves the physical path that a virtual path, either absolute or relative, maps to. (Inherited from Control.)
MemberwiseClone()Creates a shallow copy of the current Object. (Inherited from Object.)
NamingContainerGets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same ID property value. (Inherited from Control.)
OnBubbleEvent(Object, EventArgs)Determines whether the event for the server control is passed up the page's UI server control hierarchy. (Inherited from Control.)
OnDataBinding(EventArgs)Raises the DataBinding event. (Inherited from Control.)
OnInit(EventArgs)Raises the Init event. (Overrides Control.OnInit(EventArgs).)
OnLoad(EventArgs)Raises the Load event for the UpdatePanel control and invokes the Initialize() method when partial-page rendering is not enabled. (Overrides Control.OnLoad(EventArgs).)
OnPreRender(EventArgs)Raises the PreRender event. (Overrides Control.OnPreRender(EventArgs).)
OnUnload(EventArgs)Raises the base Unload event. (Overrides Control.OnUnload(EventArgs).)
OpenFile(String)Gets a Stream used to read a file. (Inherited from Control.)
PageGets a reference to the Page instance that contains the server control. (Inherited from Control.)
ParentGets a reference to the server control's parent control in the page control hierarchy. (Inherited from Control.)
PreRenderOccurs after the Control object is loaded but prior to rendering. (Inherited from Control.)
RaiseBubbleEvent(Object, EventArgs)Assigns any sources of the event and its information to the control's parent. (Inherited from Control.)
RemovedControl(Control)Called after a child control is removed from the Controls collection of the Control object. (Inherited from Control.)
Render(HtmlTextWriter)Raises the Render(HtmlTextWriter) event. (Overrides Control.Render(HtmlTextWriter).)
RenderChildren(HtmlTextWriter)Raises the RenderChildren(HtmlTextWriter) event. (Overrides Control.RenderChildren(HtmlTextWriter).)
RenderControl(HtmlTextWriter)Outputs server control content to a provided HtmlTextWriter object and stores tracing information about the control if tracing is enabled. (Inherited from Control.)
RenderControl(HtmlTextWriter, ControlAdapter)Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control.)
RenderModeGets or sets a value that indicates whether an UpdatePanel control's content is enclosed in an HTML <div> or <span> element.
RequiresUpdateGets a value that indicates whether the content of the UpdatePanel control will be updated.
ResolveAdapter()Gets the control adapter responsible for rendering the specified control. (Inherited from Control.)
ResolveClientUrl(String)Gets a URL that can be used by the browser. (Inherited from Control.)
ResolveUrl(String)Converts a URL into one that is usable on the requesting client. (Inherited from Control.)
SaveControlState()Saves any server control state changes that have occurred since the time the page was posted back to the server. (Inherited from Control.)
SaveViewState()Saves any server control view-state changes that have occurred since the time the page was posted back to the server. (Inherited from Control.)
SetDesignModeState(IDictionary)Sets design-time data for a control. (Inherited from Control.)
SetRenderMethodDelegate(RenderMethod)Assigns an event handler delegate to render the server control and its content into its parent control. (Inherited from Control.)
SiteGets information about the container that hosts the current control when rendered on a design surface. (Inherited from Control.)
SkinIDGets or sets the skin to apply to the control. (Inherited from Control.)
TemplateControlGets or sets a reference to the template that contains this control. (Inherited from Control.)
TemplateSourceDirectoryGets the virtual directory of the Page or UserControl that contains the current server control. (Inherited from Control.)
ToString()Returns a String that represents the current Object. (Inherited from Object.)
TrackViewState()Causes tracking of view-state changes to the server control so they can be stored in the server control's StateBag object. This object is accessible through the ViewState property. (Inherited from Control.)
TriggersGets an UpdatePanelTriggerCollection object that contains AsyncPostBackTrigger and PostBackTrigger objects that were registered declaratively for the UpdatePanel control.
UniqueIDGets the unique, hierarchically qualified identifier for the server control. (Inherited from Control.)
UnloadOccurs when the server control is unloaded from memory. (Inherited from Control.)
Update()Causes an update of the content of an UpdatePanel control.
UpdateModeGets or sets a value that indicates when an UpdatePanel control's content is updated.
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.)
ViewStateIgnoresCaseGets a value that indicates whether the StateBag object is case-insensitive. (Inherited from Control.)
VisibleGets or sets a value that indicates whether a server control is rendered as UI on the page. (Inherited from Control.)

Remarks

UpdatePanel controls are a central part of Microsoft ASP.NET AJAX. They are used with the ScriptManager control to enable partial-page rendering. Partial-page rendering reduces the need for synchronous postbacks and complete page updates when only part of the page has to be updated. Partial-page rendering improves the user experience because it reduces the screen flicker that occurs during a full-page postback and improves Web page interactivity.

Refreshing UpdatePanel Content

When partial-page rendering is enabled, a control can perform a postback that updates the whole page or an asynchronous postback that updates the content of one or more UpdatePanel controls. Whether a control causes an asynchronous postback and updates an UpdatePanel control depends on the following:

  • If the UpdateMode property of the UpdatePanel control is set to Always, the UpdatePanel control's content is updated on every postback that originates from the page. This includes asynchronous postbacks from controls that are inside other UpdatePanel controls and postbacks from controls that are not inside UpdatePanel controls.

  • If the UpdateMode property is set to Conditional, the UpdatePanel control's content is updated in the following circumstances:

    • When you call the Update() method of the UpdatePanel control explicitly.

    • When the UpdatePanel control is nested inside another UpdatePanel control, and the parent panel is updated.

    • When a postback is caused by a control that is defined as a trigger by using the Triggers property of the UpdatePanel control. In this scenario, the control explicitly triggers an update of the panel content. The control can be either inside or outside the UpdatePanel control that the trigger is associated with.

    • When the ChildrenAsTriggers property is set to true and a child control of the UpdatePanel control causes a postback. Child controls of nested UpdatePanel controls do not cause an update to the outer UpdatePanel control unless they are explicitly defined as triggers.

The combination of setting the ChildrenAsTriggers property to false and the UpdateMode property to Always is not allowed and will throw an exception.

UpdatePanel Usage

You can use multiple UpdatePanel controls to update different page regions independently. When the page that contains one or more UpdatePanel controls is first rendered, all the content of all UpdatePanel controls are rendered and sent to the browser. On subsequent asynchronous postbacks, the content of each UpdatePanel control might not be updated depending on the panel settings and on client or server logic for individual panels.

You can also use UpdatePanel controls in the following scenarios:

  • In user controls.

  • On master and content pages.

  • Nested inside other UpdatePanel controls.

  • Inside templated controls such as the GridView or Repeater controls.

UpdatePanel controls can be added declaratively or programmatically.

You can add an UpdatePanel control programmatically, but you cannot add triggers programmatically. To create trigger-like behavior, you can register a control on the page as an asynchronous postback control. You do this by calling the RegisterAsyncPostBackControl(Control) method of the ScriptManager control. You can then create an event handler that runs in response to the asynchronous postback, and in the handler, call the Update() method of the UpdatePanel control.

Examples

The following examples show different uses of the UpdatePanel control.

Controls Inside an UpdatePanel Control

The following example shows how to put controls inside an UpdatePanel control to reduce screen flicker when you post to the server. In this example, a Calendar and a DropDownList control are inside an UpdatePanel control. By default, the UpdateMode property is Always and the ChildrenAsTriggers property is true. Therefore, child controls of the panel cause an asynchronous postback.

Master/Detail Scenario with UpdatePanel Controls

In the following example, an UpdatePanel control is used in a master/detail scenario that shows orders and order details from the Northwind database. One UpdatePanel control contains the GridView control that displays a list of orders. A second UpdatePanel control contains a DetailsView control that displays the details of one order. When you select an order from the first table, details for that order are displayed in the second table. The second table is updated asynchronously based on the selection in the first table. The sorting and paging operations in the orders summary table also cause partial updates.

If you put a GridView control inside an UpdatePanel control, setting the GridView control's EnableSortingAndPagingCallbacks property to true is not supported. However, because the UpdatePanel control supports asynchronous postbacks, any postbacks that change the GridView control inside an UpdatePanel control cause the same behavior as sorting and paging callbacks.

Using an UpdatePanel Control in a Template

In the following example, an UpdatePanel control is used in the item template of a GridView control. UpdatePanel controls in each data row are generated automatically. Each row's UpdatePanel control contains a Label control to display the quantity of the item in that row and a Button control to decrease and increase the quantity.

Permissions

  • AspNetHostingPermission

    for operating in a hosted environment. Demand value: LinkDemand. Permission value: Minimal.

  • AspNetHostingPermission

    for operating in a hosted environment. Demand value: InheritanceDemand. Permission value: Minimal.

Inheritance Hierarchy

Object

Assembly: System.Web.Extensions (Module: System.Web.Extensions)