HtmlInputImage.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / HtmlControls / HtmlInputImage.cs / 1 / HtmlInputImage.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 * HtmlInputImage.cs 
 *
 * Copyright (c) 2000 Microsoft Corporation 
 */

namespace System.Web.UI.HtmlControls {
 
    using System;
    using System.Collections; 
    using System.Collections.Specialized; 
    using System.Globalization;
    using System.ComponentModel; 
    using System.Web;
    using System.Web.UI;
    using System.Security.Permissions;
 

///  
///     
///       The  class defines the
///       methods, properties and events for the HtmlInputImage control. This class allows 
///       programmatic access to the HTML <input type=
///       image> element on the server.
///    
///  
    [
    DefaultEvent("ServerClick"), 
    SupportsEventValidation, 
    ]
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    public class HtmlInputImage : HtmlInputControl,
    IPostBackDataHandler, IPostBackEventHandler {
 
        private static readonly object EventServerClick = new object();
        private int _x; 
        private int _y; 

 
        /*
         * Creates an intrinsic Html INPUT type=image control.
         */
 
        public HtmlInputImage() : base("image") {
        } 
 

        ///  
        ///    
        ///       Gets or sets the image
        ///       alignment within the form's content flow.
        ///     
        /// 
        /* 
         * Align property. 
         */
        [ 
        WebCategory("Appearance"),
        DefaultValue(""),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)
        ] 
        public string Align {
            get { 
                string s = Attributes["align"]; 
                return((s != null) ? s : String.Empty);
            } 
            set {
                Attributes["align"] = MapStringAttributeToString(value);
            }
        } 

 
        ///  
        ///    
        ///       Gets or sets the alternative text 
        ///       that the browser should display if the image is either unavailable or has not
        ///       been downloaded yet.
        ///    
        ///  
        /*
         * Alt property. 
         */ 
        [
        WebCategory("Appearance"), 
        DefaultValue(""),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden),
        Localizable(true)
        ] 
        public string Alt {
            get { 
                string s = Attributes["alt"]; 
                return((s != null) ? s : String.Empty);
            } 
            set {
                Attributes["alt"] = MapStringAttributeToString(value);
            }
        } 

 
        ///  
        ///    
        ///       Gets or sets the 
        ///       border width, in pixels, around the image.
        ///    
        /// 
        /* 
         * Border property, size of border in pixels.
         */ 
        [ 
        WebCategory("Appearance"),
        DefaultValue(-1), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)
        ]
        public int Border {
            get { 
                string s = Attributes["border"];
                return((s != null) ? Int32.Parse(s, CultureInfo.InvariantCulture) : -1); 
            } 
            set {
                Attributes["border"] = MapIntegerAttributeToString(value); 
            }
        }

 
        /// 
        ///     
        ///       Gets or sets the location of 
        ///       the image file relative to the page on which it is displayed.
        ///     
        /// 
        /*
         * Src property.
         */ 
        [
        WebCategory("Appearance"), 
        DefaultValue(""), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden),
        UrlProperty() 
        ]
        public string Src {
            get {
                string s = Attributes["src"]; 
                return((s != null) ? s : String.Empty);
            } 
            set { 
                Attributes["src"] = MapStringAttributeToString(value);
            } 
        }


        ///  
        ///    Gets or sets whether pressing the button causes page validation to fire. This defaults to True so that when
        ///          using validation controls, the validation state of all controls are updated when the button is clicked, both 
        ///          on the client and the server. Setting this to False is useful when defining a cancel or reset button on a page 
        ///          that has validators.
        ///  
        [
        WebCategory("Behavior"),
        DefaultValue(true),
        ] 
        public virtual bool CausesValidation {
            get { 
                object b = ViewState["CausesValidation"]; 
                return((b == null) ? true : (bool)b);
            } 
            set {
                ViewState["CausesValidation"] = value;
            }
        } 

 
        [ 
        WebCategory("Behavior"),
        DefaultValue(""), 
        WebSysDescription(SR.PostBackControl_ValidationGroup)
        ]
        public virtual string ValidationGroup {
            get { 
                string s = (string)ViewState["ValidationGroup"];
                return((s == null) ? String.Empty : s); 
            } 
            set {
                ViewState["ValidationGroup"] = value; 
            }
        }

 
        /// 
        ///     
        ///       Occurs on the server when a user clicks an  
        ///       control.
        ///     
        /// 
        [
        WebCategory("Action"),
        WebSysDescription(SR.HtmlInputImage_OnServerClick) 
        ]
        public event ImageClickEventHandler ServerClick { 
            add { 
                Events.AddHandler(EventServerClick, value);
            } 
            remove {
                Events.RemoveHandler(EventServerClick, value);
            }
        } 

 
        ///  
        /// 
        ///  
        /*
         * This method is invoked just prior to rendering.
         * Register requires handling postback to determine if image has been clicked.
         */ 
        protected internal override void OnPreRender(EventArgs e) {
            base.OnPreRender(e); 
 
            if (Page != null) {
                if (!Disabled) 
                    Page.RegisterRequiresPostBack(this);
                if (CausesValidation)
                    Page.RegisterPostBackScript();
            } 
        }
 
 

        ///  
        ///    
        ///       Raised on the server when a user clicks an 
        ///       control.
        ///     
        /// 
        /* 
         * Method used to raise the OnServerClick event. 
         */
        protected virtual void OnServerClick(ImageClickEventArgs e) { 
            ImageClickEventHandler handler = (ImageClickEventHandler)Events[EventServerClick];
            if (handler != null) handler(this, e);
        }
 

        ///  
        ///  
        /// 
        /* 
         * Method of IPostBackEventHandler interface to raise events on post back.
         * HtmlInputImage fires an OnServerClick event.
         */
        void IPostBackEventHandler.RaisePostBackEvent(string eventArgument) { 
            RaisePostBackEvent(eventArgument);
        } 
 

        ///  
        /// 
        /// 
        protected virtual void RaisePostBackEvent(string eventArgument) {
            if (CausesValidation) { 
                Page.Validate(ValidationGroup);
            } 
            OnServerClick(new ImageClickEventArgs(_x, _y)); 
        }
 

        /// 
        /// 
        ///  
        /*
         * Method of IPostBackDataHandler interface to process posted data. 
         * The image control will check to see if the x and y values were posted, 
         * which indicates that the image was clicked by the user.  The image
         * control will then register with the Page that it wants to raise an event 
         * during the event processing phase.
         */
        bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection) {
            return LoadPostData(postDataKey, postCollection); 
        }
 
 
        protected virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection) {
            string postX = postCollection[RenderedNameAttribute + ".x"]; 
            string postY = postCollection[RenderedNameAttribute + ".y"];

            if (postX != null && postY != null &&
                postX.Length > 0 && postY.Length > 0) { 

                ValidateEvent(UniqueID); 
 
                _x = Int32.Parse(postX, CultureInfo.InvariantCulture);
                _y = Int32.Parse(postY, CultureInfo.InvariantCulture); 

                Page.RegisterRequiresRaiseEvent(this);
            }
 
            return false;
        } 
 

        ///  
        /// 
        /// 
        /*
         * Method of IPostBackDataHandler interface which is invoked whenever posted data 
         * for a control has changed.
         */ 
        void IPostBackDataHandler.RaisePostDataChangedEvent() { 
            RaisePostDataChangedEvent();
        } 


        /// 
        ///  
        /// 
        protected virtual void RaisePostDataChangedEvent() { 
        } 

        /* 
         * Override to render unique name attribute.
         * The name attribute is owned by the framework.
         */
 
        /// 
        ///  
        ///  
        protected override void RenderAttributes(HtmlTextWriter writer) {
            PreProcessRelativeReferenceAttribute(writer, "src"); 

            if (Page != null) {
                Util.WriteOnClickAttribute(
                    writer, this, true, false, 
                    (CausesValidation && Page.GetValidators(ValidationGroup).Count > 0),
                    ValidationGroup); 
            } 

            base.RenderAttributes(writer); 
        }
    }
}

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