HtmlTextArea.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / HtmlControls / HtmlTextArea.cs / 1 / HtmlTextArea.cs
                        

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

/* 
 * HtmlTextArea.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.Globalization;
    using System.Security.Permissions;

 
    /// 
    ///    Defines the methods, properties, and events for the 
    ///     
    ///    class that
    ///    allows programmatic access to the HTML <textarea>. 
    /// 
    [
    DefaultEvent("ServerChange"),
    SupportsEventValidation, 
    ValidationProperty("Value")
    ] 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    public class HtmlTextArea : HtmlContainerControl, IPostBackDataHandler { 

        private static readonly object EventServerChange = new object();

        /* 
         *  Creates an intrinsic Html TEXTAREA control.
         */ 
 
        /// 
        ///    Initializes a new instance of the  class. 
        /// 
        public HtmlTextArea() : base("textarea") {
        }
 
        /*
         * The property for the number of columns to display. 
         */ 

        ///  
        ///     Indicates the display width (in characters) of the
        ///       text area.
        /// 
        [ 
        WebCategory("Appearance"),
        DefaultValue(""), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden) 
        ]
        public int Cols { 
            get {
                string s = Attributes["cols"];
                return((s != null) ? Int32.Parse(s, CultureInfo.InvariantCulture) : -1);
            } 
            set {
                Attributes["cols"] = MapIntegerAttributeToString(value); 
            } 
        }
 
        /*
         * Name property.
         */
 
        /// 
        ///     
        ///       Gets the value of the HTML 
        ///       Name attribute that will be rendered to the browser.
        ///     
        /// 
        [
        WebCategory("Behavior"),
        DefaultValue(""), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)
        ] 
        public virtual string Name { 
            get {
                return UniqueID; 
                //string s = Attributes["name"];
                //return ((s != null) ? s : "");
            }
            set { 
                //Attributes["name"] = MapStringAttributeToString(value);
            } 
        } 

        // Value that gets rendered for the Name attribute 
        internal string RenderedNameAttribute {
            get {
                return Name;
                //string name = Name; 
                //if (name.Length == 0)
                //    return UniqueID; 
 
                //return name;
            } 
        }

        /*
         * The property for the number of rows to display. 
         */
 
        ///  
        ///    Gets or sets the display height (in rows) of the text area.
        ///  
        [
        WebCategory("Appearance"),
        DefaultValue(""),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden) 
        ]
        public int Rows { 
            get { 
                string s = Attributes["rows"];
                return((s != null) ? Int32.Parse(s, CultureInfo.InvariantCulture) : -1); 
            }
            set {
                Attributes["rows"] = MapIntegerAttributeToString(value);
            } 
        }
 
 
        /// 
        ///    Gets or sets the content of the text area. 
        /// 
        [
        WebCategory("Appearance"),
        DefaultValue(""), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)
        ] 
        public string Value { 
            get {
                return InnerText; 
            }
            set {
                InnerText = value;
            } 
        }
 
 
        /// 
        /// Occurs when the content of the  control is changed upon server 
        ///    postback.
        /// 
        [
        WebCategory("Action"), 
        WebSysDescription(SR.HtmlTextArea_OnServerChange)
        ] 
        public event EventHandler ServerChange { 
            add {
                Events.AddHandler(EventServerChange, value); 
            }
            remove {
                Events.RemoveHandler(EventServerChange, value);
            } 
        }
 
 
        /// 
        ///  
        ///    Overridden to only allow literal controls to be added as Text property.
        /// 
        protected override void AddParsedSubObject(object obj) {
            if (obj is LiteralControl || obj is DataBoundLiteralControl) 
                base.AddParsedSubObject(obj);
            else 
                throw new HttpException(SR.GetString(SR.Cannot_Have_Children_Of_Type, "HtmlTextArea", obj.GetType().Name.ToString(CultureInfo.InvariantCulture))); 
        }
 

        /// 
        /// 
        ///  
        protected override void RenderAttributes(HtmlTextWriter writer) {
            if (Page != null) { 
                Page.ClientScript.RegisterForEventValidation(RenderedNameAttribute); 
            }
 
            writer.WriteAttribute("name", RenderedNameAttribute);
            Attributes.Remove("name");

            base.RenderAttributes(writer); 
        }
 
 
        /// 
        /// Raised the  
        /// event.
        /// 
        protected virtual void OnServerChange(EventArgs e) {
            EventHandler handler = (EventHandler)Events[EventServerChange]; 
            if (handler != null) handler(this, e);
        } 
 

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

            if (!Disabled) { 
                // if no change handler, no need to save posted property 
                if (Events[EventServerChange] == null) {
                    ViewState.SetItemDirty("value",false); 
                }

                if (Page != null) {
                    Page.RegisterEnabledControl(this); 
                }
            } 
        } 

        /* 
         * Method of IPostBackDataHandler interface to process posted data.
         * TextArea process a newly posted value.
         */
 
        /// 
        ///  
        ///  
        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 == null || !current.Equals(text)) {
                ValidateEvent(postDataKey); 

                Value = text;
                return true;
            } 

            return false; 
        } 

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


        ///  
        /// 
        ///  
        protected virtual void RaisePostDataChangedEvent() { 
            OnServerChange(EventArgs.Empty);
        } 
    }
}

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