Image.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / xsp / System / Web / UI / WebControls / Image.cs / 1305376 / Image.cs

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

namespace System.Web.UI.WebControls { 
 
    using System;
    using System.ComponentModel; 
    using System.Drawing.Design;
    using System.Web;
    using System.Web.UI;
    using System.Web.Util; 

    ///  
    ///    Displays an image on a page. 
    /// 
    [ 
    DefaultProperty("ImageUrl"),
    Designer("System.Web.UI.Design.WebControls.PreviewControlDesigner, " + AssemblyRef.SystemDesign),
    ]
    public class Image : WebControl { 

        private bool _urlResolved; 
 

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

 
        ///  
        ///    Specifies alternate text displayed when the image fails to load.
        ///  
        [
        Localizable(true),
        Bindable(true),
        WebCategory("Appearance"), 
        DefaultValue(""),
        WebSysDescription(SR.Image_AlternateText) 
        ] 
        public virtual string AlternateText {
            get { 
                string s = (string)ViewState["AlternateText"];
                return((s == null) ? String.Empty : s);
            }
            set { 
                ViewState["AlternateText"] = value;
            } 
        } 

 
        /// 
        /// 
        [
        DefaultValue(""), 
        Editor("System.Web.UI.Design.UrlEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor)),
        UrlProperty(), 
        WebCategory("Accessibility"), 
        WebSysDescription(SR.Image_DescriptionUrl)
        ] 
        public virtual string DescriptionUrl {
            get {
                string s = (string)ViewState["DescriptionUrl"];
                return((s == null) ? String.Empty : s); 
            }
            set { 
                ViewState["DescriptionUrl"] = value; 
            }
        } 


        /// 
        ///    Gets the font properties for the alternate text. This property is read-only. 
        /// 
        [ 
        Browsable(false), 
        EditorBrowsableAttribute(EditorBrowsableState.Never),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden), 
        ]
        public override FontInfo Font {
            // Font is meaningless for image, so hide it from the developer by
            // making it non-browsable. 
            get {
                return base.Font; 
            } 
        }
 

        [
        Browsable(false),
        EditorBrowsableAttribute(EditorBrowsableState.Never) 
        ]
        public override bool Enabled { 
            get { 
                return base.Enabled;
            } 
            set {
                base.Enabled = value;
            }
        } 

        [ 
        DefaultValue(false), 
        WebCategory("Accessibility"),
        WebSysDescription(SR.Image_GenerateEmptyAlternateText) 
        ]
        public virtual bool GenerateEmptyAlternateText {
            get {
                object o = ViewState["GenerateEmptyAlternateText"]; 
                return((o == null) ? false : (bool)o);
            } 
            set { 
                ViewState["GenerateEmptyAlternateText"] = value;
            } 
        }


        ///  
        ///    Gets or
        ///       sets the alignment of the image within the text flow. 
        ///  
        [
        WebCategory("Layout"), 
        DefaultValue(ImageAlign.NotSet),
        WebSysDescription(SR.Image_ImageAlign)
        ]
        public virtual ImageAlign ImageAlign { 
            get {
                object o = ViewState["ImageAlign"]; 
                return((o == null) ? ImageAlign.NotSet : (ImageAlign)o); 
            }
            set { 
                if (value < ImageAlign.NotSet || value > ImageAlign.TextTop) {
                    throw new ArgumentOutOfRangeException("value");
                }
                ViewState["ImageAlign"] = value; 
            }
        } 
 

        ///  
        ///    Gets or sets
        ///       the URL reference to the image to display.
        /// 
        [ 
        Bindable(true),
        WebCategory("Appearance"), 
        DefaultValue(""), 
        Editor("System.Web.UI.Design.ImageUrlEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor)),
        UrlProperty(), 
        WebSysDescription(SR.Image_ImageUrl)
        ]
        public virtual string ImageUrl {
            get { 
                string s = (string)ViewState["ImageUrl"];
                return((s == null) ? String.Empty : s); 
            } 
            set {
                ViewState["ImageUrl"] = value; 
            }
        }

        public override bool SupportsDisabledAttribute { 
            get {
                return RenderingCompatibility < VersionUtil.Framework40; 
            } 
        }
 
        // Perf work: Specially for AdRotator which uses the control while it
        // resolves the url on its own.
        internal bool UrlResolved {
            get { 
                return _urlResolved;
            } 
            set { 
                _urlResolved = value;
            } 
        }


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

            string s = ImageUrl;
            if (!UrlResolved) { 
                s = ResolveClientUrl(s);
            } 
            if (s.Length > 0 || !EnableLegacyRendering) { 
                writer.AddAttribute(HtmlTextWriterAttribute.Src, s);
            } 

            s = DescriptionUrl;
            if (s.Length != 0) {
                writer.AddAttribute(HtmlTextWriterAttribute.Longdesc, ResolveClientUrl(s)); 
            }
 
            // always write out alt for accessibility purposes 
            s = AlternateText;
            if (s.Length > 0 || GenerateEmptyAlternateText) { 
                writer.AddAttribute(HtmlTextWriterAttribute.Alt,s);
            }

            ImageAlign align = ImageAlign; 
            if (align != ImageAlign.NotSet) {
                string imageAlignValue; 
                switch (align) { 
                    case ImageAlign.Left:
                        imageAlignValue = "left"; 
                        break;
                    case ImageAlign.Right:
                        imageAlignValue = "right";
                        break; 
                    case ImageAlign.Baseline:
                        imageAlignValue = "baseline"; 
                        break; 
                    case ImageAlign.Top:
                        imageAlignValue = "top"; 
                        break;
                    case ImageAlign.Middle:
                        imageAlignValue = "middle";
                        break; 
                    case ImageAlign.Bottom:
                        imageAlignValue = "bottom"; 
                        break; 
                    case ImageAlign.AbsBottom:
                        imageAlignValue = "absbottom"; 
                        break;
                    case ImageAlign.AbsMiddle:
                        imageAlignValue = "absmiddle";
                        break; 
                    default:
                        imageAlignValue = "texttop"; 
                        break; 
                }
                writer.AddAttribute(HtmlTextWriterAttribute.Align, imageAlignValue); 
            }

            if (BorderWidth.IsEmpty && (RenderingCompatibility < VersionUtil.Framework40)) {
                if (EnableLegacyRendering) { 
                    writer.AddAttribute(HtmlTextWriterAttribute.Border, "0", false);
                } 
                else { 
                    writer.AddStyleAttribute(HtmlTextWriterStyle.BorderWidth, "0px");
                } 
            }
        }

 
        /// 
        ///  
        ///  
        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.
        }
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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