CssStyleCollection.cs source code in C# .NET

                        Code:
                         / FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / ndp / fx / src / xsp / System / Web / UI / CssStyleCollection.cs / 1 / CssStyleCollection.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

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;
 
 
    /// 
    ///     
    ///       The 
    ///       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.
    ///     
    ///  
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    public sealed class CssStyleCollection { 

        private static readonly Regex _styleAttribRegex = new Regex(
                                                                   "\\G(\\s*(;\\s*)*" +        // match leading semicolons and spaces
                                                                   "(?[^:]+?)" +    // match stylename - chars up to the semicolon 
                                                                   "\\s*:\\s*" +               // spaces, then the colon, then more spaces
                                                                   "(?[^;]*)" +      // 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.
         */
 
        /// 
        ///     
        ///       Gets or sets a specified CSS value. 
        ///    
        ///  
        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);
            } 
        }


        ///  
        /// Gets or sets the specified known CSS value.
        ///  
        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.
         */
 
        /// 
        ///     
        ///       Gets a collection of keys to all the styles in the 
        ///    .
        ///     
        /// 
        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;
            } 
        }


        ///  
        ///    
        ///       Gets the number of items in the . 
        ///     
        /// 
        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;
            } 
        }


        ///  
        ///    
        ///       Adds a style to the CssStyleCollection. 
        ///     
        /// 
        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;
        } 


        /// 
        ///     
        ///       Removes a style from the .
        ///     
        ///  
        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; 
        } 

 
        /// 
        ///    
        ///       Removes all styles from the .
        ///     
        /// 
        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; 
                    }
                }
            }
        } 

 
        ///  
        /// Render out the attribute collection into a CSS TextWriter. This
        /// effectively renders the value of an inline style attribute. 
        /// 
        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);
                }
            }
        } 

        ///  
        /// 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. 
        /// 
        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);
                }
            }
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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