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//------------------------------------------------------------------------------
// <copyright file="Image.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
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;
/// <devdoc>
/// <para>Displays an image on a page.</para>
/// </devdoc>
[
DefaultProperty("ImageUrl"),
Designer("System.Web.UI.Design.WebControls.PreviewControlDesigner, " + AssemblyRef.SystemDesign),
]
public class Image : WebControl {
private bool _urlResolved;
/// <devdoc>
/// <para>Initializes a new instance of the <see cref='System.Web.UI.WebControls.Image'/> class.</para>
/// </devdoc>
public Image() : base(HtmlTextWriterTag.Img) {
}
/// <devdoc>
/// <para>Specifies alternate text displayed when the image fails to load.</para>
/// </devdoc>
[
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;
}
}
/// <devdoc>
/// </devdoc>
[
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;
}
}
/// <devdoc>
/// <para>Gets the font properties for the alternate text. This property is read-only.</para>
/// </devdoc>
[
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;
}
}
/// <devdoc>
/// <para>Gets or
/// sets the alignment of the image within the text flow.</para>
/// </devdoc>
[
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;
}
}
/// <devdoc>
/// <para>Gets or sets
/// the URL reference to the image to display.</para>
/// </devdoc>
[
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;
}
}
/// <internalonly/>
/// <devdoc>
/// <para>Adds the attributes of an <see cref='System.Web.UI.WebControls.Image'/> to the output stream for rendering on
/// the client.</para>
/// </devdoc>
protected override void AddAttributesToRender(HtmlTextWriter writer) {
base.AddAttributesToRender(writer);
string s = ImageUrl;
if (!UrlResolved) {
s = ResolveClientUrl(s);
}
if (RenderingCompatibility >= VersionUtil.Framework45) {
// If targeting 4.5 or above, only render the 'src' attribute if it really does contain something.
// Additionally, in DesignMode include the 'src' attribute so that icon looks same as in Dev10.
// More info: Dev10 #865118; DevDiv #423125
if (!String.IsNullOrEmpty(s) || DesignMode) {
writer.AddAttribute(HtmlTextWriterAttribute.Src, s);
}
}
else {
// Otherwise, for compat, run the logic that was in the product from versions 2.0 through 4.0.
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");
}
}
}
/// <internalonly/>
/// <devdoc>
/// </devdoc>
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 <input> tag.
}
}
}
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