Button.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 / Button.cs / 2 / Button.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.Security.Permissions; 
    using System.Web;
    using System.Web.UI; 
    using System.Web.Util; 

 
    /// 
    ///    Represents a Windows button control.
    /// 
    [ 
    DataBindingHandler("System.Web.UI.Design.TextDataBindingHandler, " + AssemblyRef.SystemDesign),
    DefaultEvent("Click"), 
    DefaultProperty("Text"), 
    Designer("System.Web.UI.Design.WebControls.ButtonDesigner, " + AssemblyRef.SystemDesign),
    ToolboxData("<{0}:Button runat=\"server\" Text=\"Button\">"), 
    SupportsEventValidation
    ]
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    public class Button : WebControl, IButtonControl, IPostBackEventHandler {
 
        private static readonly object EventClick = new object(); 
        private static readonly object EventCommand = new object();
 

        /// 
        /// Initializes a new instance of the  class.
        ///  
        public Button() : base(HtmlTextWriterTag.Input) {
        } 
 

        ///  
        ///    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. 
        /// 
        [ 
        DefaultValue(true), 
        Themeable(false),
        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; 
            }
        }

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

#if SITECOUNTERS
 
        [
        DefaultValue("Button"), 
        Themeable(false), 
        WebCategory("SiteCounters"),
        WebSysDescription(SR.Control_For_SiteCounters_CounterGroup), 
        ]
        public String CounterGroup {
            get {
                String s = (String)ViewState["CounterGroup"]; 
                return((s == null) ? "Button" : 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 


        /// 
        ///    The script that is executed on a client-side click. 
        /// 
        [ 
        DefaultValue(""), 
        Themeable(false),
        WebCategory("Behavior"), 
        WebSysDescription(SR.Button_OnClientClick),
        ]
        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 or sets the text caption displayed on the  . 
        /// 
        [ 
        Bindable(true), 
        Localizable(true),
        WebCategory("Appearance"), 
        DefaultValue(""),
        WebSysDescription(SR.Button_Text),
        ]
        public string Text { 
            get {
                string s = (string)ViewState["Text"]; 
                return((s == null) ? String.Empty : s); 
            }
            set { 
                ViewState["Text"] = value;
            }
        }
 
#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
 

        ///  
        /// Whether the button should use the client's submit mechanism to implement its 
        /// behavior, or whether it should use the ASP.NET postback mechanism similar
        /// to LinkButton. By default, it uses the browser's submit mechanism. 
        /// 
        [
        DefaultValue(true),
        Themeable(false), 
        WebCategory("Behavior"),
        WebSysDescription(SR.Button_UseSubmitBehavior), 
        ] 
        public virtual bool UseSubmitBehavior {
            get { 
                object b = ViewState["UseSubmitBehavior"];
                return ((b == null) ? true : (bool)b);
            }
            set { 
                ViewState["UseSubmitBehavior"] = value;
            } 
        } 

 
        [
        DefaultValue(""),
        Themeable(false),
        WebCategory("Behavior"), 
        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 when the  is clicked.
        /// 
        [
        WebCategory("Action"), 
        WebSysDescription(SR.Button_OnClick)
        ] 
        public event EventHandler Click { 
            add {
                Events.AddHandler(EventClick, value); 
            }
            remove {
                Events.RemoveHandler(EventClick, value);
            } 
        }
 
 

        ///  
        /// Occurs when the  is clicked.
        /// 
        [
        WebCategory("Action"), 
        WebSysDescription(SR.Button_OnCommand)
        ] 
        public event CommandEventHandler Command { 
            add {
                Events.AddHandler(EventCommand, value); 
            }
            remove {
                Events.RemoveHandler(EventCommand, value);
            } 
        }
 
 
        /// 
        ///  
        /// Adds the attributes of the  control to the output stream for rendering
        ///    on the client.
        /// 
        protected override void AddAttributesToRender(HtmlTextWriter writer) { 
            bool submitButton = UseSubmitBehavior;
 
            // Make sure we are in a form tag with runat=server. 
            if (Page != null) {
                Page.VerifyRenderingInServerForm(this); 
            }

            if (submitButton) {
                writer.AddAttribute(HtmlTextWriterAttribute.Type, "submit"); 
            }
            else { 
                writer.AddAttribute(HtmlTextWriterAttribute.Type, "button"); 
            }
 
            PostBackOptions options = GetPostBackOptions();
            string uniqueID = UniqueID;

            // 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); 
            }


            writer.AddAttribute(HtmlTextWriterAttribute.Value, Text); 

            // 
 
            bool effectiveEnabled = IsEnabled;
 
            string onClick = String.Empty;

            if (effectiveEnabled) {
                // Need to merge the onclick attribute with the OnClientClick 

                // VSWhidbey 111791: Defensively add a ';' in case it is 
                // missing in user customized onClick value above. 
                onClick = Util.EnsureEndWithSemiColon(OnClientClick);
 
                if (HasAttributes) {
                    string userOnClick = Attributes["onclick"];
                    if (userOnClick != null) {
                        onClick += Util.EnsureEndWithSemiColon(userOnClick); 
                        Attributes.Remove("onclick");
                    } 
                } 

                if (Page != null) { 
                    string reference = Page.ClientScript.GetPostBackEventReference(options, false);
                    if (reference != null) {
                        onClick = Util.MergeScript(onClick, reference);
                    } 
                }
            } 
 
            if (Page != null) {
                Page.ClientScript.RegisterForEventValidation(options); 
            }

            if (onClick.Length > 0) {
                writer.AddAttribute(HtmlTextWriterAttribute.Onclick, onClick); 

                if (EnableLegacyRendering) { 
                    writer.AddAttribute("language", "javascript", false); 
                }
            } 

            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);
        } 

        protected virtual PostBackOptions GetPostBackOptions() {
            PostBackOptions options = new PostBackOptions(this, String.Empty);
            options.ClientSubmit = false; 

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

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

            return options; 
        }


        ///  
        /// Raises the event of a 
        /// . 
        ///  
        protected virtual void OnClick(EventArgs e) {
            EventHandler handler = (EventHandler)Events[EventClick]; 
            if (handler != null) handler(this,e);
        }

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

        protected internal override void OnPreRender(EventArgs e) { 
            base.OnPreRender(e);

            // VSWhidbey 489577
            if (Page != null && IsEnabled) { 
                if ((CausesValidation && Page.GetValidators(ValidationGroup).Count > 0) ||
                     !String.IsNullOrEmpty(PostBackUrl)) { 
                    Page.RegisterWebFormsScript(); 
                }
                else if (!UseSubmitBehavior) { 
                    Page.RegisterPostBackScript();
                }
            }
        } 

        ///  
        ///  
        /// 
        protected internal override void RenderContents(HtmlTextWriter writer) { 
            // Do not render the children of a button since it does not
            // make sense to have children of an  tag.
        }
 

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

 
        ///  
        /// 
        /// Raises events for the  
        /// control on post back.
        /// 
        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(EventArgs.Empty); 
            OnCommand(new CommandEventArgs(CommandName, CommandArgument));
        } 
    } 
}
                        

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