HtmlForm Class
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Provides programmatic access to the HTML <form> element on the server.
public ref class HtmlForm : System::Web::UI::HtmlControls::HtmlContainerControlpublic class HtmlForm : System.Web.UI.HtmlControls.HtmlContainerControltype HtmlForm = class
inherit HtmlContainerControlPublic Class HtmlForm
Inherits HtmlContainerControl- Inheritance
Examples
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">
</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>
</td>
</tr>
<tr align="center">
<td colspan="4">
<input type="Submit"
name="AddButton"
value="Add"
onserverclick="AddButton_Click"
runat="server"/>
<input type="Reset"
name="AddButton"
value="Reset"
runat="server"/>
</td>
<td>
</td>
</tr>
</table>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub AddButton_Click(ByVal sender As Object, ByVal e As EventArgs)
Dim Answer As Integer
' Calculate and display the result.
Answer = Convert.ToInt32(Value1.Value) + Convert.ToInt32(Value2.Value)
AnswerMessage.InnerHtml = Answer.ToString()
End Sub
</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">
</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>
</td>
</tr>
<tr align="center">
<td colspan="4">
<input type="Submit"
name="AddButton"
value="Add"
onserverclick="AddButton_Click"
runat="server"/>
<input type="Reset"
name="AddButton"
value="Reset"
runat="server"/>
</td>
<td>
</td>
</tr>
</table>
</form>
</body>
</html>
Remarks
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.
Note
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
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.
Constructors
| HtmlForm() |
Initializes a new instance of the HtmlForm class. |
Properties
| Action |
Gets or sets the action attribute of the HTML form. |
| Adapter |
Gets the browser-specific adapter for the control. (Inherited from Control) |
| AppRelativeTemplateSourceDirectory |
Gets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. (Inherited from Control) |
| Attributes |
Gets a collection of all attribute name and value pairs expressed on a server control tag within the ASP.NET page. (Inherited from HtmlControl) |
| BindingContainer |
Gets the control that contains this control's data binding. (Inherited from Control) |
| ChildControlsCreated |
Gets a value that indicates whether the server control's child controls have been created. (Inherited from Control) |
| ClientID |
Gets the control identifier that is generated by ASP.NET for the HtmlForm control. |
| ClientID |
Gets the control ID for HTML markup that is generated by ASP.NET. (Inherited from Control) |
| ClientIDMode |
Gets or sets the algorithm that is used to generate the value of the ClientID property. (Inherited from Control) |
| ClientIDSeparator |
Gets a character value representing the separator character used in the ClientID property. (Inherited from Control) |
| Context |
Gets the HttpContext object associated with the server control for the current Web request. (Inherited from Control) |
| Controls |
Gets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy. (Inherited from Control) |
| DataItemContainer |
Gets a reference to the naming container if the naming container implements IDataItemContainer. (Inherited from Control) |
| DataKeysContainer |
Gets a reference to the naming container if the naming container implements IDataKeysControl. (Inherited from Control) |
| DefaultButton |
Gets or sets the child control of the HtmlForm control that causes postback when the ENTER key is pressed. |
| DefaultFocus |
Gets or sets the control on the form to display as the control with input focus when the HtmlForm control is loaded. |
| DesignMode |
Gets a value indicating whether a control is being used on a design surface. (Inherited from Control) |
| Disabled |
Gets or sets a value indicating whether the HTML server control is disabled. (Inherited from HtmlControl) |
| EnableTheming |
Gets or sets a value indicating whether themes apply to this control. (Inherited from Control) |
| EnableViewState |
Gets or sets a value indicating whether the server control persists its view state, and the view state of any child controls it contains, to the requesting client. (Inherited from Control) |
| Enctype |
Gets or sets the encoding type a browser uses when posting the form's data to the server. |
| Events |
Gets a list of event handler delegates for the control. This property is read-only. (Inherited from Control) |
| HasChildViewState |
Gets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control) |
| ID |
Gets or sets the programmatic identifier assigned to the server control. (Inherited from Control) |
| IdSeparator |
Gets the character used to separate control identifiers. (Inherited from Control) |
| InnerHtml |
Gets or sets the content found between the opening and closing tags of the specified HTML server control. (Inherited from HtmlContainerControl) |
| InnerText |
Gets or sets the text between the opening and closing tags of the specified HTML server control. (Inherited from HtmlContainerControl) |
| IsChildControlStateCleared |
Gets a value indicating whether controls contained within this control have control state. (Inherited from Control) |
| IsTrackingViewState |
Gets a value that indicates whether the server control is saving changes to its view state. (Inherited from Control) |
| IsViewStateEnabled |
Gets a value indicating whether view state is enabled for this control. (Inherited from Control) |
| LoadViewStateByID |
Gets a value indicating whether the control participates in loading its view state by ID instead of index. (Inherited from Control) |
| Method |
Gets or sets a value that indicates how a browser posts form data to the server for processing. |
| Name |
Gets the identifier name for the HtmlForm control. |
| NamingContainer |
Gets 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) |
| Page |
Gets a reference to the Page instance that contains the server control. (Inherited from Control) |
| Parent |
Gets a reference to the server control's parent control in the page control hierarchy. (Inherited from Control) |
| RenderingCompatibility |
Gets a value that specifies the ASP.NET version that rendered HTML will be compatible with. (Inherited from Control) |
| Site |
Gets information about the container that hosts the current control when rendered on a design surface. (Inherited from Control) |
| SkinID |
Gets or sets the skin to apply to the control. (Inherited from Control) |
| Style |
Gets a collection of all cascading style sheet (CSS) properties applied to a specified HTML server control in the ASP.NET file. (Inherited from HtmlControl) |
| SubmitDisabledControls |
Gets 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. |
| TagName |
Gets the element name of a tag that contains a |
| Target |
Gets or sets the frame or window in which to render the results of information that is posted to the server. |
| TemplateControl |
Gets or sets a reference to the template that contains this control. (Inherited from Control) |
| TemplateSourceDirectory |
Gets the virtual directory of the Page or UserControl that contains the current server control. (Inherited from Control) |
| UniqueID |
Gets the unique programmatic identifier assigned to the HtmlForm control. |
| ValidateRequestMode |
Gets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values. (Inherited from Control) |
| ViewState |
Gets a dictionary of state information that allows you to save and restore the view state of a server control across multiple requests for the same page. (Inherited from Control) |
| ViewStateIgnoresCase |
Gets a value that indicates whether the HtmlControl view state is case-sensitive. (Inherited from HtmlControl) |
| ViewStateMode |
Gets or sets the view-state mode of this control. (Inherited from Control) |
| Visible |
Gets or sets a value that indicates whether a server control is rendered as UI on the page. (Inherited from Control) |
Methods
| 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) |
| BeginRenderTracing(TextWriter, Object) |
Begins design-time tracing of rendering data. (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) |
| ClearCachedClientID() |
Sets the cached ClientID value to |
| 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) |
| ClearEffectiveClientIDMode() |
Sets the ClientIDMode property of the current control instance and of any child controls to Inherit. (Inherited from Control) |
| 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) |
| CreateControlCollection() |
Creates a new ControlCollection collection for the HtmlForm control. |
| CreateControlCollection() |
Creates a new ControlCollection object to hold the child controls (both literal and server) of the server control. (Inherited from HtmlContainerControl) |
| 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) |
| Dispose() |
Enables a server control to perform final clean up before it is released from memory. (Inherited from Control) |
| EndRenderTracing(TextWriter, Object) |
Ends design-time tracing of rendering data. (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) |
| FindControl(String, Int32) |
Searches the current naming container for a server control with the specified |
| FindControl(String) |
Searches the current naming container for a server control with the specified |
| Focus() |
Sets input focus to a control. (Inherited from Control) |
| GetAttribute(String) |
Gets the value of the named attribute on the HtmlControl control. (Inherited from HtmlControl) |
| GetDesignModeState() |
Gets design-time data for a control. (Inherited from Control) |
| GetHashCode() |
Serves as the default hash function. (Inherited from Object) |
| GetRouteUrl(Object) |
Gets the URL that corresponds to a set of route parameters. (Inherited from Control) |
| GetRouteUrl(RouteValueDictionary) |
Gets the URL that corresponds to a set of route parameters. (Inherited from Control) |
| GetRouteUrl(String, Object) |
Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control) |
| GetRouteUrl(String, RouteValueDictionary) |
Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control) |
| GetType() |
Gets the Type of the current instance. (Inherited from Object) |
| GetUniqueIDRelativeTo(Control) |
Returns the prefixed portion of the UniqueID property of the specified control. (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) |
| IsLiteralContent() |
Determines if the server control holds only literal content. (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 the HtmlContainerControl control's view state from a previous page request that was saved by the SaveViewState() method. (Inherited from HtmlContainerControl) |
| 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) |
| 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) | |
| OnLoad(EventArgs) |
Raises the Load event. (Inherited from Control) |
| OnPreRender(EventArgs) | |
| OnPreRender(EventArgs) |
Raises the PreRender event. (Inherited from Control) |
| OnUnload(EventArgs) |
Raises the Unload event. (Inherited from Control) |
| OpenFile(String) |
Gets a Stream used to read a file. (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) |
Renders the HtmlForm control to the specified HtmlTextWriter object. |
| RenderAttributes(HtmlTextWriter) |
Renders the HtmlForm control's attributes to the specified HtmlTextWriter object. |
| RenderBeginTag(HtmlTextWriter) |
Renders the opening HTML tag of the control into the specified HtmlTextWriter object. (Inherited from HtmlControl) |
| RenderChildren(HtmlTextWriter) |
Renders the child controls of the HtmlForm control. |
| RenderControl(HtmlTextWriter, ControlAdapter) |
Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control) |
| RenderControl(HtmlTextWriter) |
Renders the HtmlForm control to the specified HtmlTextWriter object. |
| 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) |
| RenderEndTag(HtmlTextWriter) |
Renders the closing tag for the HtmlContainerControl control to the specified HtmlTextWriter object. (Inherited from HtmlContainerControl) |
| 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) |
| SetAttribute(String, String) |
Sets the value of the named attribute on the HtmlControl control. (Inherited from HtmlControl) |
| 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) |
| 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) |
| 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) |
| 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) |
Events
| DataBinding |
Occurs when the server control binds to a data source. (Inherited from Control) |
| Disposed |
Occurs when a server control is released from memory, which is the last stage of the server control lifecycle when an ASP.NET page is requested. (Inherited from Control) |
| Init |
Occurs when the server control is initialized, which is the first step in its lifecycle. (Inherited from Control) |
| Load |
Occurs when the server control is loaded into the Page object. (Inherited from Control) |
| PreRender |
Occurs after the Control object is loaded but prior to rendering. (Inherited from Control) |
| Unload |
Occurs when the server control is unloaded from memory. (Inherited from Control) |
Explicit Interface Implementations
Extension Methods
| FindDataSourceControl(Control) |
Returns the data source that is associated with the data control for the specified control. |
| FindFieldTemplate(Control, String) |
Returns the field template for the specified column in the specified control's naming container. |
| FindMetaTable(Control) |
Returns the metatable object for the containing data control. |
