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//------------------------------------------------------------------------------
// <copyright file="CssStyleCollection.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.UI {
using System.IO;
using System.Collections;
using System.Collections.Specialized;
using System.Reflection;
using System.Web.UI;
using System.Text;
using System.Text.RegularExpressions;
using System.Security.Permissions;
/// <devdoc>
/// <para>
/// The <see langword='CssStyleCollection'/>
/// class contains HTML
/// cascading-style sheets (CSS) inline style attributes. It automatically parses
/// and exposes CSS properties through a dictionary pattern API. Each CSS key can be
/// manipulated using a key/value indexed collection.
/// </para>
/// </devdoc>
public sealed class CssStyleCollection {
private static readonly Regex _styleAttribRegex = new Regex(
"\\G(\\s*(;\\s*)*" + // match leading semicolons and spaces
"(?<stylename>[^:]+?)" + // match stylename - chars up to the semicolon
"\\s*:\\s*" + // spaces, then the colon, then more spaces
"(?<styleval>[^;]*)" + // now match styleval
")*\\s*(;\\s*)*$", // match a trailing semicolon and trailing spaces
RegexOptions.Singleline |
RegexOptions.Multiline |
RegexOptions.ExplicitCapture);
private StateBag _state;
private string _style;
private IDictionary _table;
private IDictionary _intTable;
internal CssStyleCollection() : this(null) {
}
/*
* Constructs an CssStyleCollection given a StateBag.
*/
internal CssStyleCollection(StateBag state) {
_state = state;
}
/*
* Automatically adds new keys.
*/
/// <devdoc>
/// <para>
/// Gets or sets a specified CSS value.
/// </para>
/// </devdoc>
public string this[string key] {
get {
if (_table == null)
ParseString();
string value = (string)_table[key];
if (value == null) {
HtmlTextWriterStyle style = CssTextWriter.GetStyleKey(key);
if (style != (HtmlTextWriterStyle)(-1)) {
value = this[style];
}
}
return value;
}
set {
Add(key, value);
}
}
/// <devdoc>
/// Gets or sets the specified known CSS value.
/// </devdoc>
public string this[HtmlTextWriterStyle key] {
get {
if (_intTable == null) {
return null;
}
return (string)_intTable[(int)key];
}
set {
Add(key, value);
}
}
/*
* Returns a collection of keys.
*/
/// <devdoc>
/// <para>
/// Gets a collection of keys to all the styles in the
/// <see langword='CssStyleCollection'/>.
/// </para>
/// </devdoc>
public ICollection Keys {
get {
if (_table == null)
ParseString();
if (_intTable != null) {
// combine the keys into a single table. Note that to preserve existing
// behavior, we convert enum values into strings to maintain a homogeneous collection.
string[] keys = new string[_table.Count + _intTable.Count];
int i = 0;
foreach (string s in _table.Keys) {
keys[i] = s;
i++;
}
foreach (HtmlTextWriterStyle style in _intTable.Keys) {
keys[i] = CssTextWriter.GetStyleName(style);
i++;
}
return keys;
}
return _table.Keys;
}
}
/// <devdoc>
/// <para>
/// Gets the number of items in the <see langword='CssStyleCollection'/>.
/// </para>
/// </devdoc>
public int Count {
get {
if (_table == null)
ParseString();
return _table.Count + ((_intTable != null) ? _intTable.Count : 0);
}
}
public string Value {
get {
if (_state == null) {
if (_style == null) {
_style = BuildString();
}
return _style;
}
return(string)_state["style"];
}
set {
if (_state == null) {
_style = value;
}
else {
_state["style"] = value;
}
_table = null;
}
}
/// <devdoc>
/// <para>
/// Adds a style to the CssStyleCollection.
/// </para>
/// </devdoc>
public void Add(string key, string value) {
if (String.IsNullOrEmpty(key)) {
throw new ArgumentNullException("key");
}
if (_table == null)
ParseString();
_table[key] = value;
if (_intTable != null) {
// Remove from the other table to avoid duplicates.
HtmlTextWriterStyle style = CssTextWriter.GetStyleKey(key);
if (style != (HtmlTextWriterStyle)(-1)) {
_intTable.Remove(style);
}
}
if (_state != null) {
// keep style attribute synchronized
_state["style"] = BuildString();
}
_style = null;
}
public void Add(HtmlTextWriterStyle key, string value) {
if (_intTable == null) {
_intTable = new HybridDictionary();
}
_intTable[(int)key] = value;
string name = CssTextWriter.GetStyleName(key);
if (name.Length != 0) {
// Remove from the other table to avoid duplicates.
if (_table == null)
ParseString();
_table.Remove(name);
}
if (_state != null) {
// keep style attribute synchronized
_state["style"] = BuildString();
}
_style = null;
}
/// <devdoc>
/// <para>
/// Removes a style from the <see langword='CssStyleCollection'/>.
/// </para>
/// </devdoc>
public void Remove(string key) {
if (_table == null)
ParseString();
if (_table[key] != null) {
_table.Remove(key);
if (_state != null) {
// keep style attribute synchronized
_state["style"] = BuildString();
}
_style = null;
}
}
public void Remove(HtmlTextWriterStyle key) {
if (_intTable == null) {
return;
}
_intTable.Remove((int)key);
if (_state != null) {
// keep style attribute synchronized
_state["style"] = BuildString();
}
_style = null;
}
/// <devdoc>
/// <para>
/// Removes all styles from the <see langword='CssStyleCollection'/>.
/// </para>
/// </devdoc>
public void Clear() {
_table = null;
_intTable = null;
if (_state != null) {
_state.Remove("style");
}
_style = null;
}
/* BuildString
* Form the style string from data contained in the
* hash table
*/
private string BuildString() {
// if the tables are null, there is nothing to build
if (((_table == null) || (_table.Count == 0)) &&
((_intTable == null) || (_intTable.Count == 0))) {
return null;
}
StringWriter sw = new StringWriter();
CssTextWriter writer = new CssTextWriter(sw);
Render(writer);
return sw.ToString();
}
/* ParseString
* Parse the style string and fill the hash table with
* corresponding values.
*/
private void ParseString() {
// create a case-insensitive dictionary
_table = new HybridDictionary(true);
string s = (_state == null) ? _style : (string)_state["style"];
if (s != null) {
Match match;
if ((match = _styleAttribRegex.Match( s, 0)).Success) {
CaptureCollection stylenames = match.Groups["stylename"].Captures;
CaptureCollection stylevalues = match.Groups["styleval"].Captures;
for (int i = 0; i < stylenames.Count; i++) {
String styleName = stylenames[i].ToString();
String styleValue = stylevalues[i].ToString();
_table[styleName] = styleValue;
}
}
}
}
/// <devdoc>
/// Render out the attribute collection into a CSS TextWriter. This
/// effectively renders the value of an inline style attribute.
/// </devdoc>
internal void Render(CssTextWriter writer) {
if (_table != null && _table.Count > 0) {
foreach (DictionaryEntry entry in _table) {
writer.WriteAttribute((string)entry.Key, (string)entry.Value);
}
}
if (_intTable != null && _intTable.Count > 0) {
foreach (DictionaryEntry entry in _intTable) {
writer.WriteAttribute((HtmlTextWriterStyle)entry.Key, (string)entry.Value);
}
}
}
/// <devdoc>
/// Render out the attribute collection into a CSS TextWriter. This
/// effectively renders the value of an inline style attribute.
/// Used by a Style object to render out its CSS attributes into an HtmlTextWriter.
/// </devdoc>
internal void Render(HtmlTextWriter writer) {
if (_table != null && _table.Count > 0) {
foreach (DictionaryEntry entry in _table) {
writer.AddStyleAttribute((string)entry.Key, (string)entry.Value);
}
}
if (_intTable != null && _intTable.Count > 0) {
foreach (DictionaryEntry entry in _intTable) {
writer.AddStyleAttribute((HtmlTextWriterStyle)entry.Key, (string)entry.Value);
}
}
}
}
}
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