ImageButton.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / WebControls / ImageButton.cs / 2 / ImageButton.cs
                        

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

/* 
 */ 

namespace System.Web.UI.WebControls { 

    using System;
    using System.Collections;
    using System.Collections.Specialized; 
    using System.ComponentModel;
    using System.Drawing.Design; 
    using System.Globalization; 
    using System.Security.Permissions;
    using System.Web; 
    using System.Web.UI;
    using System.Web.Util;

 
    /// 
    ///    Creates a control that displays an image, responds to mouse clicks, 
    ///       and records the mouse pointer position. 
    /// 
    [ 
    DefaultEvent("Click"),
    Designer("System.Web.UI.Design.WebControls.PreviewControlDesigner, " + AssemblyRef.SystemDesign),
    SupportsEventValidation,
    ] 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    public class ImageButton : Image, IPostBackDataHandler, IPostBackEventHandler, IButtonControl { 

        private static readonly object EventClick = new object(); 
        private static readonly object EventButtonClick = new object();
        private static readonly object EventCommand = new object();

        private int x = 0; 
        private int y = 0;
 
 
        /// 
        /// Initializes a new instance of the  class. 
        /// 
        public ImageButton() {
        }
 

        ///  
        /// Gets or sets the command associated with the  that is propogated in the  event along with the  
        /// property.
        ///  
        [
        DefaultValue(""),
        WebCategory("Behavior"),
        WebSysDescription(SR.WebControl_CommandName), 
        Themeable(false),
        ] 
        public string CommandName { 
            get {
                string s = (string)ViewState["CommandName"]; 
                return((s == null) ? String.Empty : s);
            }
            set {
                ViewState["CommandName"] = value; 
            }
        } 
 

        ///  
        ///    Gets or sets an optional argument that is propogated in
        ///       the  event with the associated
        ///    
        ///    property. 
        /// 
        [ 
        Bindable(true), 
        DefaultValue(""),
        Themeable(false), 
        WebCategory("Behavior"),
        WebSysDescription(SR.WebControl_CommandArgument),
        ]
        public string CommandArgument { 
            get {
                string s = (string)ViewState["CommandArgument"]; 
                return((s == null) ? String.Empty : s); 
            }
            set { 
                ViewState["CommandArgument"] = 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.
        /// 
        [
        Themeable(false), 
        DefaultValue(true),
        WebCategory("Behavior"), 
        WebSysDescription(SR.Button_CausesValidation) 
        ]
        public virtual bool CausesValidation { 
            get {
                object b = ViewState["CausesValidation"];
                return((b == null) ? true : (bool)b);
            } 
            set {
                ViewState["CausesValidation"] = value; 
            } 
        }
 
#if SITECOUNTERS

        [
        DefaultValue("ImageButton"), 
        Themeable(false),
        WebCategory("SiteCounters"), 
        WebSysDescription(SR.Control_For_SiteCounters_CounterGroup), 
        ]
        public String CounterGroup { 
            get {
                String s = (String)ViewState["CounterGroup"];
                return((s == null) ? "ImageButton" : s);
            } 
            set {
                ViewState["CounterGroup"] = value; 
            } 
        }
 

        [
        DefaultValue(""),
        Themeable(false), 
        WebCategory("SiteCounters"),
        WebSysDescription(SR.Control_For_SiteCounters_CounterName), 
        ] 
        public String CounterName {
            get { 
                String s = (String)ViewState["CounterName"];
                return((s == null) ? String.Empty : s);
            }
            set { 
                ViewState["CounterName"] = value;
            } 
        } 

 
        [
        DefaultValue(false),
        Themeable(false),
        WebCategory("SiteCounters"), 
        WebSysDescription(SR.Control_For_SiteCounters_CountClicks),
        ] 
        public bool CountClicks { 
            get {
                object b = ViewState["CountClicks"]; 
                return((b == null) ? false : (bool)b);
            }
            set {
                ViewState["CountClicks"] = value; 
            }
        } 
#endif 

 
        [
        Browsable(true),
        EditorBrowsableAttribute(EditorBrowsableState.Always),
        Bindable(true), 
        WebCategory("Behavior"),
        DefaultValue(true), 
        WebSysDescription(SR.WebControl_Enabled) 
        ]
        public override bool Enabled { 
            get {
                return base.Enabled;
            }
            set { 
                base.Enabled = value;
            } 
        } 

        [ 
        Browsable(false),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden),
        EditorBrowsable(EditorBrowsableState.Never),
        Themeable(false), 
        ]
        public override bool GenerateEmptyAlternateText { 
            get { 
                return base.GenerateEmptyAlternateText;
            } 
            set {
                throw new NotSupportedException(SR.GetString(
                    SR.Property_Set_Not_Supported, "GenerateEmptyAlternateText", this.GetType().ToString()));
            } 
        }
 
 
        /// 
        ///    The script that is executed on a client-side click. 
        /// 
        [
        DefaultValue(""),
        WebCategory("Behavior"), 
        WebSysDescription(SR.Button_OnClientClick),
        Themeable(false), 
        ] 
        public virtual string OnClientClick {
            get { 
                string s = (string)ViewState["OnClientClick"];
                if (s == null) {
                    return String.Empty;
                } 
                return s;
            } 
            set { 
                ViewState["OnClientClick"] = value;
            } 
        }


        [ 
        DefaultValue(""),
        Editor("System.Web.UI.Design.UrlEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor)), 
        Themeable(false), 
        UrlProperty("*.aspx"),
        WebCategory("Behavior"), 
        WebSysDescription(SR.Button_PostBackUrl),
        ]
        public virtual string PostBackUrl {
            get { 
                string s = (string)ViewState["PostBackUrl"];
                return s == null? String.Empty : s; 
            } 
            set {
                ViewState["PostBackUrl"] = value; 
            }
        }
#if SITECOUNTERS
 
        [
        DefaultValue(-1), 
        Themeable(false), 
        WebCategory("SiteCounters"),
        WebSysDescription(SR.Control_For_SiteCounters_RowsPerDay), 
        ]
        public int RowsPerDay {
            get {
                Object o = ViewState["RowsPerDay"]; 
                return((o == null) ? -1 : (int) o);
            } 
            set { 
                if (value == 0) {
                    throw new ArgumentOutOfRangeException("value"); 
                }
                ViewState["RowsPerDay"] = value;
            }
        } 

 
        [ 
        DefaultValue(""),
        Themeable(false), 
        WebCategory("SiteCounters"),
        WebSysDescription(SR.Control_For_SiteCounters_SiteCountersProvider),
        ]
        public String SiteCountersProvider { 
            get {
                String s = (String) ViewState["SiteCountersProvider"]; 
                return((s != null) ? s : String.Empty); 
            }
            set { 
                ViewState["SiteCountersProvider"] = value;
            }
        }
#endif 

        ///  
        ///     Gets a value that represents the tag HtmlTextWriterTag.Input. This property is read-only. 
        /// 
        [ 
        Browsable(false),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)
        ]
        protected override HtmlTextWriterTag TagKey { 
            get {
                return HtmlTextWriterTag.Input; 
            } 
        }
#if SITECOUNTERS 

        [
        DefaultValue(true),
        Themeable(false), 
        WebCategory("SiteCounters"),
        WebSysDescription(SR.Control_For_SiteCounters_TrackApplicationName), 
        ] 
        public bool TrackApplicationName {
            get { 
                object b = ViewState["TrackApplicationName"];
                return((b == null) ? true : (bool)b);
            }
            set { 
                ViewState["TrackApplicationName"] = value;
            } 
        } 

 
        [
        DefaultValue(true),
        Themeable(false),
        WebCategory("SiteCounters"), 
        WebSysDescription(SR.Control_For_SiteCounters_TrackPageUrl),
        ] 
        public bool TrackPageUrl { 
            get {
                object b = ViewState["TrackPageUrl"]; 
                return((b == null) ? true : (bool)b);
            }
            set {
                ViewState["TrackPageUrl"] = value; 
            }
        } 
#endif 

        [ 
        WebCategory("Behavior"),
        Themeable(false),
        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;
            } 
        }
 
 
        /// 
        /// Represents the method that will handle the  event of an . 
        /// 
        [
        WebCategory("Action"),
        WebSysDescription(SR.ImageButton_OnClick) 
        ]
        public event ImageClickEventHandler Click { 
            add { 
                Events.AddHandler(EventClick, value);
            } 
            remove {
                Events.RemoveHandler(EventClick, value);
            }
        } 

 
        ///  
        /// Represents the method that will handle the  event of an .
        ///  
        event EventHandler IButtonControl.Click {
            add {
                Events.AddHandler(EventButtonClick, value);
            } 
            remove {
                Events.RemoveHandler(EventButtonClick, value); 
            } 
        }
 

        /// 
        /// Represents the method that will handle the  event of an .
        ///  
        [
        WebCategory("Action"), 
        WebSysDescription(SR.ImageButton_OnCommand) 
        ]
        public event CommandEventHandler Command { 
            add {
                Events.AddHandler(EventCommand, value);
            }
            remove { 
                Events.RemoveHandler(EventCommand, value);
            } 
        } 

 
        /// 
        /// 
        /// Adds the attributes of an  to the output
        ///    stream for rendering on the client. 
        /// 
        protected override void AddAttributesToRender(HtmlTextWriter writer) { 
            Page page = Page; 

            // Make sure we are in a form tag with runat=server. 
            if (page != null) {
                page.VerifyRenderingInServerForm(this);
            }
 
            writer.AddAttribute(HtmlTextWriterAttribute.Type,"image");
 
            string uniqueID = UniqueID; 
            PostBackOptions options = GetPostBackOptions();
 
            // Don't render Name on a button if __doPostBack is posting back to a different control
            // because Page will register this control as requiring post back notification even though
            // it's not the target of the postback.  If the TargetControl isn't this control, this control's
            // RaisePostBackEvent should never get called.  See VSWhidbey 477095. 
            if (uniqueID != null && (options == null || options.TargetControl == this)) {
                writer.AddAttribute(HtmlTextWriterAttribute.Name, uniqueID); 
            } 

            // 

            bool effectiveEnabled = IsEnabled;

 
            string onClick = String.Empty;
 
            if (effectiveEnabled) { 
                // Need to merge the onclick attribute with the OnClientClick
                onClick = Util.EnsureEndWithSemiColon(OnClientClick); 
                if (HasAttributes) {
                    string userOnClick = Attributes["onclick"];
                    if (userOnClick != null) {
                        onClick += Util.EnsureEndWithSemiColon(userOnClick); 
                        Attributes.Remove("onclick");
                    } 
                } 
            }
 
            if (Enabled && !effectiveEnabled) {
                // We need to do the cascade effect on the server, because the browser
                // only renders as disabled, but doesn't disable the functionality.
                writer.AddAttribute(HtmlTextWriterAttribute.Disabled, "disabled"); 
            }
 
            base.AddAttributesToRender(writer); 

            if (page != null && options != null) { 
                page.ClientScript.RegisterForEventValidation(options);

                if (effectiveEnabled) {
                    string postBackEventReference = page.ClientScript.GetPostBackEventReference(options, false); 
                    if (!String.IsNullOrEmpty(postBackEventReference)) {
                        onClick = Util.MergeScript(onClick, postBackEventReference); 
                    } 
                }
            } 

            if (onClick.Length > 0) {
                writer.AddAttribute(HtmlTextWriterAttribute.Onclick, onClick);
 
                if (EnableLegacyRendering) {
                    writer.AddAttribute("language", "javascript", false); 
                } 
            }
        } 

        // Returns the client post back options.
        protected virtual PostBackOptions GetPostBackOptions() {
            PostBackOptions options = new PostBackOptions(this, String.Empty); 
            // The postback script ends up in onclick, not href,
            // so we shouldn't force the javascript protocol like we do in LinkButton. 
            options.ClientSubmit = false; 

            if (!String.IsNullOrEmpty(PostBackUrl)) { 
                options.ActionUrl = HttpUtility.UrlPathEncode(ResolveClientUrl(PostBackUrl));
            }

            if (CausesValidation && Page != null && Page.GetValidators(ValidationGroup).Count > 0) { 
                options.PerformValidation = true;
                options.ValidationGroup = ValidationGroup; 
            } 

            return options; 
        }


        ///  
        /// 
        /// Processes posted data for the  control. 
        ///  
        bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection) {
            return LoadPostData(postDataKey, postCollection); 
        }


        ///  
        /// 
        /// Processes posted data for the  control. 
        ///  
        protected virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection) {
            string name = UniqueID; 
            string postX = postCollection[name + ".x"];
            string postY = postCollection[name + ".y"];
            if (postX != null && postY != null && postX.Length > 0 && postY.Length > 0) {
                x = Int32.Parse(postX, CultureInfo.InvariantCulture); 
                y = Int32.Parse(postY, CultureInfo.InvariantCulture);
                if (Page != null) { 
                    Page.RegisterRequiresRaiseEvent(this); 
                }
            } 
            return false;
        }

 
        /// 
        /// Raises the  event. 
        ///  
        protected virtual void OnClick(ImageClickEventArgs e) {
            ImageClickEventHandler onClickHandler = (ImageClickEventHandler)Events[EventClick]; 
            if (onClickHandler != null) onClickHandler(this,e);

            EventHandler onButtonClickHandler = (EventHandler)Events[EventButtonClick];
            if (onButtonClickHandler != null) onButtonClickHandler(this,(EventArgs)e); 
        }
 
 
        /// 
        /// Raises the  event. 
        /// 
        protected virtual void OnCommand(CommandEventArgs e) {
            CommandEventHandler onCommandHandler = (CommandEventHandler)Events[EventCommand];
            if (onCommandHandler != null) 
                onCommandHandler(this,e);
 
            // Command events are bubbled up the control heirarchy 
            RaiseBubbleEvent(this, e);
        } 


        /// 
        ///  
        ///    
        ///       Determine 
        ///       if the image has been clicked prior to rendering on the client.  
        /// 
        protected internal override void OnPreRender(EventArgs e) { 
            base.OnPreRender(e);
            if (Page != null) {
                Page.RegisterRequiresPostBack(this);
 
                if (IsEnabled &&
                    ((CausesValidation && Page.GetValidators(ValidationGroup).Count > 0) || 
                     !String.IsNullOrEmpty(PostBackUrl))) { 
                    Page.RegisterWebFormsScript();  // VSWhidbey 489577
                } 
            }
        }

 
        /// 
        ///  
        /// Raises events on post back for the  
        /// control.
        ///  
        void IPostBackEventHandler.RaisePostBackEvent(string eventArgument) {
            RaisePostBackEvent(eventArgument);
        }
 

        ///  
        ///  
        /// Raises events on post back for the 
        /// control. 
        /// 
        protected virtual void RaisePostBackEvent(string eventArgument) {
            ValidateEvent(this.UniqueID, eventArgument);
 
#if SITECOUNTERS
            SiteCounters siteCounters = Context.SiteCounters; 
            if (siteCounters.Enabled && CountClicks) { 
                String counterName = CounterName;
                if (counterName.Length == 0) { 
                    counterName = ID;
                }
                siteCounters.Write(CounterGroup, counterName, SiteCounters.ClickEventText,
                                   null, TrackApplicationName, TrackPageUrl, 
                                   SiteCountersProvider, RowsPerDay);
            } 
#endif 
            if (CausesValidation) {
                Page.Validate(ValidationGroup); 
            }
            OnClick(new ImageClickEventArgs(x,y));
            OnCommand(new CommandEventArgs(CommandName, CommandArgument));
 
        }
 
 
        /// 
        ///  
        /// Raised when posted data for a control has changed.
        /// 
        void IPostBackDataHandler.RaisePostDataChangedEvent() {
            RaisePostDataChangedEvent(); 
        }
 
 
        /// 
        ///  
        /// Raised when posted data for a control has changed.
        /// 
        protected virtual void RaisePostDataChangedEvent() {
        } 

 
        ///  
        /// 
        /// IButtonControl.Text implementation.  IButtonControl is used internally for adaptive rendering, but 
        /// property is explicitly implemented because the developer should use AlternateText, as in V1.
        /// 
        string IButtonControl.Text {
            get { 
                return Text;
            } 
            set { 
                Text = value;
            } 
        }


        ///  
        /// 
        /// IButtonControl.Text implementation.  IButtonControl is used internally for adaptive rendering, but 
        /// property is explicitly implemented because the developer should use AlternateText, as in V1. 
        /// 
        protected virtual string Text { 
            get {
                return AlternateText;
            }
            set { 
                AlternateText = value;
            } 
        } 
    }
}

Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK