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//------------------------------------------------------------------------------
// <copyright file="HtmlInputHidden.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
/*
* HtmlInputHidden.cs
*
* Copyright (c) 2000 Microsoft Corporation
*/
namespace System.Web.UI.HtmlControls {
using System.ComponentModel;
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Web;
using System.Web.UI;
using System.Security.Permissions;
/// <devdoc>
/// <para>
/// The <see langword='HtmlInputHidden'/> class defines the methods, properties,
/// and events of the HtmlInputHidden control. This class allows programmatic access
/// to the HTML <input type=hidden> element on the server.
/// </para>
/// </devdoc>
[
DefaultEvent("ServerChange"),
SupportsEventValidation,
]
public class HtmlInputHidden : HtmlInputControl, IPostBackDataHandler {
private static readonly object EventServerChange = new object();
/*
* Creates an intrinsic Html INPUT type=hidden control.
*/
public HtmlInputHidden() : base("hidden") {
}
/// <devdoc>
/// <para>
/// Occurs when the <see langword='HtmlInputHidden'/> control
/// is changed on the server.
/// </para>
/// </devdoc>
[
WebCategory("Action"),
WebSysDescription(SR.HtmlInputHidden_OnServerChange)
]
public event EventHandler ServerChange {
add {
Events.AddHandler(EventServerChange, value);
}
remove {
Events.RemoveHandler(EventServerChange, value);
}
}
/*
* Method used to raise the OnServerChange event.
*/
/// <devdoc>
/// <para>
/// Raised on the server when the <see langword='HtmlInputHidden'/> control
/// changes between postback requests.
/// </para>
/// </devdoc>
protected virtual void OnServerChange(EventArgs e) {
EventHandler handler = (EventHandler)Events[EventServerChange];
if (handler != null) handler(this, e);
}
/*
*
*/
/// <internalonly/>
/// <devdoc>
/// </devdoc>
protected internal override void OnPreRender(EventArgs e) {
base.OnPreRender(e);
// if no change handler, no need to save posted property
if (!Disabled) {
if (Events[EventServerChange] == null) {
ViewState.SetItemDirty("value",false);
}
if (Page != null) {
Page.RegisterEnabledControl(this);
}
}
}
/*
* Method of IPostBackDataHandler interface to process posted data.
* InputText process a newly posted value.
*/
/// <internalonly/>
/// <devdoc>
/// </devdoc>
bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection) {
return LoadPostData(postDataKey, postCollection);
}
protected virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection) {
string current = Value;
string text = postCollection.GetValues(postDataKey)[0];
if (!current.Equals(text)) {
ValidateEvent(postDataKey);
Value = text;
return true;
}
return false;
}
protected override void RenderAttributes(HtmlTextWriter writer) {
base.RenderAttributes(writer);
if (Page != null) {
Page.ClientScript.RegisterForEventValidation(RenderedNameAttribute);
}
}
/*
* Method of IPostBackDataHandler interface which is invoked whenever posted data
* for a control has changed. TextBox fires an OnTextChanged event.
*/
/// <internalonly/>
/// <devdoc>
/// </devdoc>
void IPostBackDataHandler.RaisePostDataChangedEvent() {
RaisePostDataChangedEvent();
}
/// <internalonly/>
/// <devdoc>
/// </devdoc>
protected virtual void RaisePostDataChangedEvent() {
OnServerChange(EventArgs.Empty);
}
}
}
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