Label.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 / Label.cs / 1 / Label.cs
                        

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

namespace System.Web.UI.WebControls { 
 
    using System;
    using System.Collections; 
    using System.ComponentModel;
    using System.Drawing.Design;
    using System.Security.Permissions;
    using System.Web; 
    using System.Web.UI;
 
 

    ///  
    /// Interacts with the parser to build a  control.
    /// 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    public class LabelControlBuilder : ControlBuilder {
 
 
        /// 
        ///  
        ///    Specifies whether white space literals are allowed.
        /// 
        public override bool AllowWhitespaceLiterals() {
            return false; 
        }
    } 
 

 
    /// 
    ///    Constructs a label for displaying text programmatcially on a
    ///       page.
    ///  
    [
    ControlBuilderAttribute(typeof(LabelControlBuilder)), 
    ControlValueProperty("Text"), 
    DataBindingHandler("System.Web.UI.Design.TextDataBindingHandler, " + AssemblyRef.SystemDesign),
    DefaultProperty("Text"), 
    ParseChildren(false),
    Designer("System.Web.UI.Design.WebControls.LabelDesigner, " + AssemblyRef.SystemDesign),
    ToolboxData("<{0}:Label runat=\"server\" Text=\"Label\">")
    ] 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    public class Label : WebControl, ITextControl { 

 
        /// 
        /// Initializes a new instance of the  class and renders
        ///    it as a SPAN tag.
        ///  
        public Label() {
        } 
 

        ///  
        /// 
        internal Label(HtmlTextWriterTag tag) : base(tag) {
        }
 

        ///  
        /// [To be supplied.] 
        /// 
        [ 
        DefaultValue(""),
        IDReferenceProperty(),
        TypeConverter(typeof(AssociatedControlConverter)),
        WebCategory("Accessibility"), 
        WebSysDescription(SR.Label_AssociatedControlID),
        Themeable(false) 
        ] 
        public virtual string AssociatedControlID {
            get { 
                string s = (string)ViewState["AssociatedControlID"];
                return (s == null) ? String.Empty : s;
            }
            set { 
                ViewState["AssociatedControlID"] = value;
            } 
        } 

        internal bool AssociatedControlInControlTree { 
            get {
                object o = ViewState["AssociatedControlNotInControlTree"];
                return (o == null ? true : (bool)o);
            } 
            set {
                ViewState["AssociatedControlNotInControlTree"] = value; 
            } 
        }
 

        internal override bool RequiresLegacyRendering {
            get {
                return true; 
            }
        } 
 

        protected override HtmlTextWriterTag TagKey { 
            get {
                if (AssociatedControlID.Length != 0) {
                    return HtmlTextWriterTag.Label;
                } 
                return base.TagKey;
            } 
        } 

 
        /// 
        /// Gets or sets the text content of the 
        /// control.
        ///  
        [
        Localizable(true), 
        Bindable(true), 
        WebCategory("Appearance"),
        DefaultValue(""), 
        WebSysDescription(SR.Label_Text),
        PersistenceMode(PersistenceMode.InnerDefaultProperty)
        ]
        public virtual string Text { 
            get {
                object o = ViewState["Text"]; 
                return((o == null) ? String.Empty : (string)o); 
            }
            set { 
                if (HasControls()) {
                    Controls.Clear();
                }
                ViewState["Text"] = value; 
            }
        } 
 

        protected override void AddAttributesToRender(HtmlTextWriter writer) { 
            string associatedControlID = AssociatedControlID;
            if (associatedControlID.Length != 0) {
                if (AssociatedControlInControlTree) {
                    Control wc = FindControl(associatedControlID); 
                    if (wc == null) {
                        // Don't throw in the designer. 
                        if (!DesignMode) 
                            throw new HttpException(SR.GetString(SR.LabelForNotFound, associatedControlID, ID));
                    } 
                    else {
                        writer.AddAttribute(HtmlTextWriterAttribute.For, wc.ClientID);
                    }
                } 
                else {
                    writer.AddAttribute(HtmlTextWriterAttribute.For, associatedControlID); 
                } 
            }
 
            base.AddAttributesToRender(writer);
        }

 
        /// 
        ///  
        ///  
        protected override void AddParsedSubObject(object obj) {
            if (HasControls()) { 
                base.AddParsedSubObject(obj);
            }
            else {
                if (obj is LiteralControl) { 
                    Text = ((LiteralControl)obj).Text;
                } 
                else { 
                    string currentText = Text;
                    if (currentText.Length != 0) { 
                        Text = String.Empty;
                        base.AddParsedSubObject(new LiteralControl(currentText));
                    }
                    base.AddParsedSubObject(obj); 
                }
            } 
        } 

 
        /// 
        /// 
        ///    Load previously saved state.
        ///       Overridden to synchronize Text property with LiteralContent. 
        /// 
        protected override void LoadViewState(object savedState) { 
            if (savedState != null) { 
                base.LoadViewState(savedState);
                string s = (string)ViewState["Text"]; 
                if (s != null)
                    Text = s;
            }
        } 

 
        ///  
        /// 
        /// Renders the contents of the  into the specified writer. 
        /// 
        protected internal override void RenderContents(HtmlTextWriter writer) {
            if (HasRenderingData()) {
                base.RenderContents(writer); 
            }
            else { 
                writer.Write(Text); 
            }
        } 
    }
}

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