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HtmlForm Class

Provides programmatic access to the HTML <form> element on the server.

Namespace:  System.Web.UI.HtmlControls
Assembly:  System.Web (in System.Web.dll)
public class HtmlForm : HtmlContainerControl
<asp:HtmlForm />

The HtmlForm type exposes the following members.

  NameDescription
Public methodHtmlFormInitializes a new instance of the HtmlForm class.
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  NameDescription
Public propertyActionGets or sets the action attribute of the HTML form.
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 a collection of all attribute name and value pairs expressed on a server control tag within the ASP.NET page. (Inherited from HtmlControl.)
Public propertyBindingContainerInfrastructure. Gets the control that contains this control's data binding. (Inherited from Control.)
Protected propertyChildControlsCreatedGets a value that indicates whether the server control's child controls have been created. (Inherited from Control.)
Public propertyClientIDGets the control identifier that is generated by ASP.NET for the HtmlForm control (Overrides Control.ClientID.)
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.)
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 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.)
Public propertyDefaultButtonGets or sets the child control of the HtmlForm control that causes postback when the ENTER key is pressed.
Public propertyDefaultFocusGets or sets the control on the form to display as the control with input focus when the HtmlForm control is loaded.
Protected propertyDesignModeGets a value indicating whether a control is being used on a design surface. (Inherited from Control.)
Public propertyDisabledGets or sets a value indicating whether the HTML server control is disabled. (Inherited from HtmlControl.)
Public propertyEnableThemingGets or sets a value indicating whether themes apply to this control. (Inherited from Control.)
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.)
Public propertyEnctypeGets or sets the encoding type a browser uses when posting the form's data to the server.
Protected propertyEventsGets a list of event handler delegates for the control. This property is read-only. (Inherited from Control.)
Protected propertyHasChildViewStateGets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control.)
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.)
Public propertyInnerHtmlGets or sets the content found between the opening and closing tags of the specified HTML server control. (Inherited from HtmlContainerControl.)
Public propertyInnerTextGets or sets the text between the opening and closing tags of the specified HTML server control. (Inherited from HtmlContainerControl.)
Protected propertyIsChildControlStateClearedGets a value indicating whether controls contained within this control have control state. (Inherited from Control.)
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 propertyMethodGets or sets a value that indicates how a browser posts form data to the server for processing.
Public propertyNameGets the identifier name for the HtmlForm 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 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 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 Control.)
Public propertyStyleGets a collection of all cascading style sheet (CSS) properties applied to a specified HTML server control in the ASP.NET file. (Inherited from HtmlControl.)
Public propertySubmitDisabledControlsGets or sets a Boolean value indicating whether to force controls disabled on the client to submit their values, allowing them to preserve their values after the page posts back to the server.
Public propertyTagNameGets the element name of a tag that contains a runat=server attribute and value pair. (Inherited from HtmlControl.)
Public propertyTargetGets or sets the frame or window in which to render the results of information that is posted to the server.
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 propertyUniqueIDGets the unique programmatic identifier assigned to the HtmlForm control. (Overrides Control.UniqueID.)
Public propertyValidateRequestModeGets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values. (Inherited from Control.)
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 HtmlControl view state is case-sensitive. (Inherited from HtmlControl.)
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.)
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  NameDescription
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 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.)
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 collection for the HtmlForm control. (Overrides HtmlContainerControl.CreateControlCollection().)
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 methodGetAttributeGets the value of the named attribute on the HtmlControl control. (Inherited from HtmlControl.)
Protected methodGetDesignModeStateInfrastructure. Gets design-time data for a control. (Inherited from Control.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
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 the HtmlContainerControl control's view state from a previous page request that was saved by the SaveViewState method. (Inherited from HtmlContainerControl.)
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.)
Protected methodOnBubbleEventDetermines whether the event for the server control is passed up the page's UI server control hierarchy. (Inherited from Control.)
Protected methodOnDataBindingRaises the DataBinding event. (Inherited from Control.)
Protected methodOnInitRaises the Init event for the HtmlForm control. (Overrides Control.OnInit(EventArgs).)
Protected methodOnLoadRaises the Load event. (Inherited from Control.)
Protected methodOnPreRenderRaises the PreRender event for the HtmlForm control. (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 methodRemovedControlCalled after a child control is removed from the Controls collection of the Control object. (Inherited from Control.)
Protected methodRenderRenders the HtmlForm control to the specified HtmlTextWriter object. (Overrides HtmlContainerControl.Render(HtmlTextWriter).)
Protected methodRenderAttributesRenders the HtmlForm control's attributes to the specified HtmlTextWriter object. (Overrides HtmlContainerControl.RenderAttributes(HtmlTextWriter).)
Protected methodRenderBeginTagRenders the opening HTML tag of the control into the specified HtmlTextWriter object. (Inherited from HtmlControl.)
Protected methodRenderChildrenRenders the child controls of the HtmlForm control. (Overrides Control.RenderChildren(HtmlTextWriter).)
Public methodRenderControl(HtmlTextWriter)Renders the HtmlForm control to the specified HtmlTextWriter object. (Overrides Control.RenderControl(HtmlTextWriter).)
Protected methodRenderControl(HtmlTextWriter, ControlAdapter)Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control.)
Protected methodRenderEndTagRenders the closing tag for the HtmlContainerControl control to the specified HtmlTextWriter object. (Inherited from HtmlContainerControl.)
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 server control view-state changes that have occurred since the time the page was posted back to the server. (Inherited from Control.)
Protected methodSetAttributeSets the value of the named attribute on the HtmlControl control. (Inherited from HtmlControl.)
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 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 Control.ViewState property. (Inherited from Control.)
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  NameDescription
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. For a description of this member, see IAttributeAccessor.GetAttribute. (Inherited from HtmlControl.)
Explicit interface implemetationPrivate methodIAttributeAccessor.SetAttributeInfrastructure. For a description of this member, see IAttributeAccessor.SetAttribute. (Inherited from HtmlControl.)
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.)
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The HtmlForm control is a container for server controls on a Web Forms page. All server controls that post back to the server must be placed between the opening and closing tags of an HtmlForm control.

NoteNote

ASP.NET allows only a single HtmlForm control to be active on a Web Forms page. If there is more than one active HtmlForm control on a Web Forms page, the common language runtime will throw an System.Web.HttpException exception when you request the page. You can, however, use a MultiView control where each View object contains one HtmlForm control, because only one View is active at any given time.

You can control the behavior of the HtmlForm control by setting its properties. To specify the encoding type for the form's data, set the Enctype property. The method (GET or POST) that a browser uses to post form data to the server for processing is specified by setting the Method property.

Caution noteCaution

By default, the Method property is set to POST. You can modify the value of this property to GET, but this might break the built-in state and postback services provided by the ASP.NET page framework.

You can configure controls that implement the IButtonControl interface to post to a different target page. This is referred to as cross-page posting. For more information, see Cross-Page Posting in ASP.NET Web Forms.

For a list of initial property values for an instance of HtmlForm, see the HtmlForm constructor.

The following code example demonstrates how to use the HtmlForm class to create a simple form.

<%@ 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">

<script runat="server">

    protected void AddButton_Click(Object sender, EventArgs e)
    {

        int Answer;

        // Calculate and display the result.
        Answer = Convert.ToInt32(Value1.Value) + Convert.ToInt32(Value2.Value);
        AnswerMessage.InnerHtml = Answer.ToString();

    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" > 
<head>
  <title>HtmlForm Example</title>
</head>
<body>

   <form method="Post"
         enctype="application/x-www-form-urlencoded" 
         runat="server" id="myform">

      <h3> HtmlForm Example </h3>

      <table>
         <tr>
            <td colspan="5">
               Enter integer values into the text boxes. <br />
               Click the Add button to add the two values. <br />
               Click the Reset button to reset the text boxes.
            </td>
         </tr>
         <tr>
            <td colspan="5">
               &nbsp;
            </td>
         </tr>
         <tr align="center">
            <td>
               <input id="Value1"
                      type="Text"
                      size="2"
                      maxlength="3"
                      value="1"
                      runat="server"/>
            </td>
            <td>
               + 
            </td>
            <td>
               <input id="Value2"
                      type="Text"
                      size="2"
                      maxlength="3"
                      value="1"
                      runat="server"/>
            </td>
            <td>
               =
            </td>
            <td>
               <span id="AnswerMessage"
                     runat="server"/>
            </td>
         </tr>
         <tr>
            <td colspan="2">
               <asp:RequiredFieldValidator
                    ID="Value1RequiredValidator"
                    ControlToValidate="Value1"
                    ErrorMessage="Please enter a value.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value1MinCompareValidator"
                    ControlToValidate="Value1"
                    Operator="LessThan"
                    Type="Integer"
                    ValueToCompare="100"
                    ErrorMessage="Please enter an integer less than 100.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value1MaxCompareValidator"
                    ControlToValidate="Value1"
                    Operator="GreaterThan"
                    Type="Integer"
                    ValueToCompare="0"
                    ErrorMessage="Please enter an integer greater than 0.<br />"
                    Display="Dynamic"
                    runat="server"/>
            </td>
            <td colspan="2">
               <asp:RequiredFieldValidator
                    ID="Value2RequiredValidator"
                    ControlToValidate="Value2"
                    ErrorMessage="Please enter a value.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value2MinCompareValidator"
                    ControlToValidate="Value2"
                    Operator="LessThan"
                    Type="Integer"
                    ValueToCompare="100"
                    ErrorMessage="Please enter an integer less than 100.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value2MaxCompareValidator"
                    ControlToValidate="Value2"
                    Operator="GreaterThan"
                    Type="Integer"
                    ValueToCompare="0"
                    ErrorMessage="Please enter an integer greater than 0.<br />"
                    Display="Dynamic"
                    runat="server"/>

            </td>
            <td>
               &nbsp;
            </td>
         </tr>
         <tr align="center">
            <td colspan="4">
               <input type="Submit"
                      name="AddButton"
                      value="Add"
                      onserverclick="AddButton_Click"
                      runat="server"/>

               &nbsp;&nbsp;&nbsp;

               <input type="Reset"
                      name="AddButton"
                      value="Reset"
                      runat="server"/>
            </td>
            <td>
               &nbsp;
            </td>
         </tr>
      </table>

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

.NET Framework

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

Windows Phone 8.1, Windows Phone 8, 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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