context: //
  // System.Web.UI.WebControls.ImageButton.cs
  //
  // Authors:
  //	Jordi Mas i Hernandez (jordi@ximian.com)
  //
  // (C) 2005-2010 Novell, Inc (http://www.novell.com)
  //
  //
  //
  // Permission is hereby granted, free of charge, to any person obtaining
  // a copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to
  // permit persons to whom the Software is furnished to do so, subject to
  // the following conditions:
  //
  // The above copyright notice and this permission notice shall be
  // included in all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  //
  
  using System.Collections.Specialized;
  using System.ComponentModel;
  using System.Security.Permissions;
  
  namespace System.Web.UI.WebControls
  {
  	// CAS
  	[AspNetHostingPermissionAttribute (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  	[AspNetHostingPermissionAttribute (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  	// attributes
  	[DefaultEvent("Click")]
  	[Designer ("System.Web.UI.Design.WebControls.PreviewControlDesigner, " + Consts.AssemblySystem_Design, "System.ComponentModel.Design.IDesigner")]
  	[SupportsEventValidation]
  	public class ImageButton : Image, IPostBackDataHandler, IPostBackEventHandler, IButtonControl
  	{
  		static readonly object ClickEvent = new object ();
  		static readonly object CommandEvent = new object ();
  		int pos_x, pos_y;
  
  		public ImageButton ()
  		{
  
  		}
  
  		[DefaultValue(true)]
  		[WebSysDescription ("")]
  		[WebCategory ("Behavior")]
  		[Themeable (false)]
  		public virtual bool CausesValidation {
  			get { return ViewState.GetBool ("CausesValidation", true); }
  			set { ViewState ["CausesValidation"] = value; }
  		}
  
  		[Bindable(true)]
  		[DefaultValue("")]
  		[WebSysDescription ("")]
  		[WebCategory ("Behavior")]
  		[Themeable (false)]
  		public string CommandArgument {
  			get { return ViewState.GetString ("CommandArgument", String.Empty); }
  			set { ViewState ["CommandArgument"] = value; }
  		}
  
  		[DefaultValue("")]
  		[WebSysDescription ("")]
  		[WebCategory ("Behavior")]
  		[Themeable (false)]
  		public string CommandName {
  			get { return ViewState.GetString ("CommandName", String.Empty); }
  			set { ViewState ["CommandName"] = value; }
  		}
  
  		[EditorBrowsable (EditorBrowsableState.Always)]
  		[Browsable (true)]
  		[DefaultValue (true)]
  		[Bindable (true)]
  		public virtual new bool Enabled {
  			// Should there be any special code below? Doesn't look so...
  			get { return base.Enabled; }
  			set { base.Enabled = value; }
  		}
  
  		[Browsable (false)]
  		[EditorBrowsable (EditorBrowsableState.Never)]
  		[Themeable (false)]
  		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  		public override bool GenerateEmptyAlternateText {
  			get { return false; }
  			set { throw new NotSupportedException (); }
  		}
  
  		[DefaultValue ("")]
  		[Themeable (false)]
  		public virtual string OnClientClick {
  			get { return ViewState.GetString ("OnClientClick", String.Empty); }
  			set { ViewState ["OnClientClick"] = value; }
  		}
  
  		[Themeable (false)]
  		[UrlProperty ("*.aspx")]
  		[DefaultValue ("")]
  		[Editor ("System.Web.UI.Design.UrlEditor, "  + Consts.AssemblySystem_Design, "System.Drawing.Design.UITypeEditor, " + Consts.AssemblySystem_Drawing)]
  		public virtual string PostBackUrl {
  			get { return ViewState.GetString ("PostBackUrl", String.Empty); }
  			set { ViewState["PostBackUrl"] = value; }
  		}
  
  		[Themeable (false)]
  		[DefaultValue ("")]
  		[WebSysDescription ("")]
  		[WebCategory ("Behavior")]
  		public virtual string ValidationGroup {
  			get { return ViewState.GetString ("ValidationGroup", String.Empty); }
  			set { ViewState ["ValidationGroup"] = value; }
  		}
  
  		[Browsable(false)]
  		[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
  		protected override HtmlTextWriterTag TagKey {
  			get { return HtmlTextWriterTag.Input; }
  		}
  
  		// Gets or sets the value of the ImageButton control's AlternateText property. (MSDN)
  		protected virtual string Text {
  			get { return AlternateText; }
  			set { AlternateText = value; }
  		}
  #if NET_4_0
  		public override bool SupportsDisabledAttribute {
  			get { return RenderingCompatibilityLessThan40; }
  		}
  #endif
  		protected override void AddAttributesToRender (HtmlTextWriter writer)
  		{			
  			Page page = Page;
  			if (page != null)
  				page.VerifyRenderingInServerForm (this);
  			
  			writer.AddAttribute (HtmlTextWriterAttribute.Type, "image", false);
  			writer.AddAttribute (HtmlTextWriterAttribute.Name, UniqueID);
  
  			base.AddAttributesToRender (writer);
  
  			string onclick = OnClientClick;
  			if (!String.IsNullOrEmpty (onclick))
  				onclick = ClientScriptManager.EnsureEndsWithSemicolon (onclick);
  			else
  				onclick = String.Empty;
  			
  			if (HasAttributes && Attributes ["onclick"] != null) {
  				onclick = ClientScriptManager.EnsureEndsWithSemicolon (onclick + Attributes ["onclick"]);
  				Attributes.Remove ("onclick");
  			}
  			
  			if (page != null)
  				onclick += GetClientScriptEventReference ();
  			
  			if (onclick.Length > 0)
  				writer.AddAttribute (HtmlTextWriterAttribute.Onclick, onclick);
  		}
  
  		internal virtual string GetClientScriptEventReference ()
  		{
  			PostBackOptions options = GetPostBackOptions ();
  			Page page = Page;
  			
  			if (options.PerformValidation || !String.IsNullOrEmpty (options.ActionUrl))
  				return page != null ? page.ClientScript.GetPostBackEventReference (options, true) : String.Empty;
  			else {
  				if (page != null)
  					page.ClientScript.RegisterForEventValidation (options);
  				return String.Empty;
  			}
  		}
  
  		protected virtual PostBackOptions GetPostBackOptions ()
  		{
  			PostBackOptions options = new PostBackOptions (this);
  			Page page = Page;
  			
  			options.ActionUrl = (PostBackUrl.Length > 0 ?
  #if TARGET_J2EE
  					     CreateActionUrl (PostBackUrl)
  #else
  					     (page != null ? page.ResolveClientUrl (PostBackUrl) : null)
  #endif
  					     : null);
  
  			options.Argument = String.Empty;
  			options.ClientSubmit = true;
  			options.RequiresJavaScriptProtocol = true;
  			options.PerformValidation = CausesValidation && page != null && page.AreValidatorsUplevel (ValidationGroup);
  			if (options.PerformValidation)
  				options.ValidationGroup = ValidationGroup;
  			else
  				options.ValidationGroup = null;
  			
  			return options;
  		}
  
  		protected virtual bool LoadPostData (string postDataKey, NameValueCollection postCollection) 
  		{
  			string x, y;
  			string unique = UniqueID;
  			x = postCollection [unique + ".x"];
  			y = postCollection [unique + ".y"];
  			if (!String.IsNullOrEmpty (x) && !String.IsNullOrEmpty (y)) {
  				pos_x = Int32.Parse(x);
  				pos_y = Int32.Parse(y);
  				Page.RegisterRequiresRaiseEvent (this);
  				return true;
  			} else {
  				x = postCollection [unique];
  				if (!String.IsNullOrEmpty (x)) {
  					pos_x = Int32.Parse (x);
  					pos_y = 0;
  					Page.RegisterRequiresRaiseEvent (this);
  					return true;
  				}
  			}
  
  			return false;
  		}
  
  		protected virtual void RaisePostDataChangedEvent ()
  		{
  		}
  		
  		protected virtual void RaisePostBackEvent (string eventArgument)
  		{
  			ValidateEvent (UniqueID, String.Empty);
  			if (CausesValidation) {
  				Page page = Page;
  				if (page != null)
  					page.Validate (ValidationGroup);
  			}
  			
  			OnClick (new ImageClickEventArgs (pos_x, pos_y));
  			OnCommand (new CommandEventArgs (CommandName, CommandArgument));
  		}
  
  		bool IPostBackDataHandler.LoadPostData (string postDataKey, NameValueCollection postCollection)
  		{
  			return LoadPostData (postDataKey, postCollection);
  		}
  
  
  		void IPostBackDataHandler.RaisePostDataChangedEvent ()
  		{
  			RaisePostDataChangedEvent ();
  		}
  
  		void IPostBackEventHandler.RaisePostBackEvent (string eventArgument)
  		{
  			RaisePostBackEvent (eventArgument);
  		}
  
  		protected virtual void OnClick (ImageClickEventArgs e)
  		{
  			if (Events != null) {
  				ImageClickEventHandler eh = (ImageClickEventHandler) (Events [ClickEvent]);
  				if (eh != null)
  					eh (this, e);
  			}
  		}
  
  		protected virtual void OnCommand (CommandEventArgs e)
  		{
  			if (Events != null) {
  				CommandEventHandler eh = (CommandEventHandler) (Events [CommandEvent]);
  				if (eh != null)
  					eh (this, e);
  			}
  
  			RaiseBubbleEvent (this, e);
  		}
  
  		protected internal override void OnPreRender (EventArgs e)
  		{
  			Page page = Page;
  			if (page != null && IsEnabled)
  				page.RegisterRequiresPostBack (this);
  		}
  
  		[WebSysDescription ("")]
  		[WebCategory ("Action")]
  		public event ImageClickEventHandler Click {
  			add { Events.AddHandler (ClickEvent, value); }
  
gt: 			remove { Events.RemoveHandler (ClickEvent, value); }