ColorConverter.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / whidbey / netfxsp / ndp / fx / src / CommonUI / System / Drawing / ColorConverter.cs / 1 / ColorConverter.cs

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

/* 
 */ 
namespace System.Drawing {
    using System.Runtime.Serialization.Formatters; 
    using System.Runtime.InteropServices;
    using System.Diagnostics;
    using System.Diagnostics.CodeAnalysis;
    using Microsoft.Win32; 
    using System.Collections;
    using System.ComponentModel; 
    using System.ComponentModel.Design.Serialization; 
    using System.Globalization;
    using System.Reflection; 
    using System.Threading;

    /// 
    ///  
    ///      ColorConverter is a class that can be used to convert
    ///      colors from one data type to another.  Access this 
    ///      class through the TypeDescriptor. 
    /// 
    public class ColorConverter : TypeConverter { 
        private static string ColorConstantsLock = "colorConstants";
        private static Hashtable colorConstants;
        private static string SystemColorConstantsLock = "systemColorConstants";
        private static Hashtable systemColorConstants; 
        private static string ValuesLock = "values";
        private static StandardValuesCollection values; 
 
        /// 
        ///  
        ///    [To be supplied.]
        /// 
        public ColorConverter() {
        } 

        ///  
        ///  
        ///      Hashtable of color / value pairs (color name is key)
        ///      for standard colors. 
        /// 
        private static Hashtable Colors {
            get {
                if (colorConstants == null) { 
                    lock(ColorConstantsLock) {
                        if (colorConstants == null) { 
                            Hashtable tempHash = new Hashtable(StringComparer.OrdinalIgnoreCase); 
                            FillConstants(tempHash, typeof(Color));
                            colorConstants = tempHash; 
                        }
                    }
                }
 
                return colorConstants;
            } 
        } 

        ///  
        /// 
        ///      Hashtable of color / value pairs (color name is key)
        ///      for system colors.
        ///  
        private static Hashtable SystemColors {
            get { 
                if (systemColorConstants == null) { 
                    lock (SystemColorConstantsLock) {
                        if (systemColorConstants == null) { 
                            Hashtable tempHash = new Hashtable(StringComparer.OrdinalIgnoreCase);
                            FillConstants(tempHash, typeof(System.Drawing.SystemColors));
                            systemColorConstants = tempHash;
                        } 
                    }
                } 
 
                return systemColorConstants;
            } 
        }

        /// 
        ///  
        ///      Determines if this converter can convert an object in the given source
        ///      type to the native type of the converter. 
        ///  
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
            if (sourceType == typeof(string)) { 
                return true;
            }
            return base.CanConvertFrom(context, sourceType);
        } 

        ///  
        ///  
        ///    Gets a value indicating whether this converter can
        ///       convert an object to the given destination type using the context. 
        /// 
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) {
            if (destinationType == typeof(InstanceDescriptor)) {
                return true; 
            }
            return base.CanConvertTo(context, destinationType); 
        } 

        internal static object GetNamedColor(string name) { 
            object color = null;
            // First, check to see if this is a standard name.
            //
            color = Colors[name]; 
            if (color != null) {
                return color; 
            } 
            // Ok, how about a system color?
            // 
            color = SystemColors[name];
            return color;
        }
 
        /// 
        ///  
        ///      Converts the given object to the converter's native type. 
        /// 
        [SuppressMessage("Microsoft.Performance", "CA1808:AvoidCallsThatBoxValueTypes")] 
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
            string strValue = value as string;
            if (strValue != null) {
                object obj = null; 
                string text = strValue.Trim();
 
                if (text.Length == 0) { 
                    obj = Color.Empty;
                } 
                else {
                    // First, check to see if this is a standard name.
                    //
                    obj = GetNamedColor(text); 

                    if (obj == null) { 
                        if (culture == null) { 
                            culture = CultureInfo.CurrentCulture;
                        } 

                        char sep = culture.TextInfo.ListSeparator[0];
                        bool tryMappingToKnownColor = true;
 
                        TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
 
                        // If the value is a 6 digit hex number only, then 
                        // we want to treat the Alpha as 255, not 0
                        // 
                        if (text.IndexOf(sep) == -1) {

                            // text can be '' (empty quoted string)
                            if (text.Length >= 2 && (text[0] == '\'' || text[0] == '"') && text[0] == text[text.Length -1]) { 
                                // In quotes means a named value
                                string colorName = text.Substring(1, text.Length - 2); 
                                obj = Color.FromName(colorName); 
                                tryMappingToKnownColor = false;
                            } 
                            else if ((text.Length == 7 && text[0] == '#') ||
                                     (text.Length == 8 && (text.StartsWith("0x") || text.StartsWith("0X"))) ||
                                     (text.Length == 8 && (text.StartsWith("&h") || text.StartsWith("&H")))) {
                                // Note: ConvertFromString will raise exception if value cannot be converted. 
                                obj = Color.FromArgb(unchecked((int)(0xFF000000 | (uint)(int)intConverter.ConvertFromString(context, culture, text))));
                            } 
                        } 

                        // Nope.  Parse the RGBA from the text. 
                        //
                        if (obj == null) {
                            string[] tokens = text.Split(new char[] {sep});
                            int[] values = new int[tokens.Length]; 
                            for (int i = 0; i < values.Length; i++) {
                                values[i] = (int)intConverter.ConvertFromString(context, culture, tokens[i]); 
                            } 

                            // We should now have a number of parsed integer values. 
                            // We support 1, 3, or 4 arguments:
                            //
                            // 1 -- full ARGB encoded
                            // 3 -- RGB 
                            // 4 -- ARGB
                            // 
                            switch (values.Length) { 
                                case 1:
                                    obj = Color.FromArgb(values[0]); 
                                    break;

                                case 3:
                                    obj = Color.FromArgb(values[0], values[1], values[2]); 
                                    break;
 
                                case 4: 
                                    obj = Color.FromArgb(values[0], values[1], values[2], values[3]);
                                    break; 
                            }
                            tryMappingToKnownColor = true;
                        }
 
                        if ((obj != null) && tryMappingToKnownColor) {
 
                            // Now check to see if this color matches one of our known colors. 
                            // If it does, then substitute it.  We can only do this for "Colors"
                            // because system colors morph with user settings. 
                            //
                            int targetARGB = ((Color)obj).ToArgb();

                            foreach (Color c in Colors.Values) { 
                                if (c.ToArgb() == targetARGB) {
                                    obj = c; 
                                    break; 
                                }
                            } 
                        }
                    }

                    if (obj == null) { 
                        throw new ArgumentException(SR.GetString(SR.InvalidColor, text));
                    } 
                } 
                return obj;
            } 
            return base.ConvertFrom(context, culture, value);
        }

        ///  
        /// 
        ///      Converts the given object to another type.  The most common types to convert 
        ///      are to and from a string object.  The default implementation will make a call 
        ///      to ToString on the object if the object is valid and if the destination
        ///      type is string.  If this cannot convert to the desitnation type, this will 
        ///      throw a NotSupportedException.
        /// 
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
            if (destinationType == null) { 
                throw new ArgumentNullException("destinationType");
            } 
 
            if( value is Color ){
                if (destinationType == typeof(string)) { 
                    Color c = (Color)value;

                    if (c == Color.Empty) {
                        return string.Empty; 
                    }
                    else { 
                        // If this is a known color, then Color can provide its own 
                        // name.  Otherwise, we fabricate an ARGB value for it.
                        // 
                        if (c.IsKnownColor) {
                            return c.Name;
                        }
                        else if (c.IsNamedColor) { 
                            return "'" + c.Name + "'";
                        } 
                        else { 
                            if (culture == null) {
                                culture = CultureInfo.CurrentCulture; 
                            }
                            string sep = culture.TextInfo.ListSeparator + " ";
                            TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
                            string[] args; 
                            int nArg = 0;
 
                            if (c.A < 255) { 
                                args = new string[4];
                                args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.A); 
                            }
                            else {
                                args = new string[3];
                            } 

                            // Note: ConvertToString will raise exception if value cannot be converted. 
                            args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.R); 
                            args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.G);
                            args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.B); 

                            // Now slam all of these together with the fantastic Join
                            // method.
                            // 
                            return string.Join(sep, args);
                        } 
                    } 
                }
                if (destinationType == typeof(InstanceDescriptor)) { 
                    MemberInfo member = null;
                    object[] args = null;

                    Color c = (Color)value; 

                    if (c.IsEmpty) { 
                        member = typeof(Color).GetField("Empty"); 
                    }
                    else if (c.IsSystemColor) { 
                        member = typeof(SystemColors).GetProperty(c.Name);
                    }
                    else if (c.IsKnownColor) {
                        member = typeof(Color).GetProperty(c.Name); 
                    }
                    else if (c.A != 255) { 
                        member = typeof(Color).GetMethod("FromArgb", new Type[] {typeof(int), typeof(int), typeof(int), typeof(int)}); 
                        args = new object[] {c.A, c.R, c.G, c.B};
                    } 
                    else if (c.IsNamedColor) {
                        member = typeof(Color).GetMethod("FromName", new Type[] {typeof(string)});
                        args = new object[] {c.Name};
                    } 
                    else {
                        member = typeof(Color).GetMethod("FromArgb", new Type[] {typeof(int), typeof(int), typeof(int)}); 
                        args = new object[] {c.R, c.G, c.B}; 
                    }
 
                    Debug.Assert(member != null, "Could not convert color to member.  Did someone change method name / signature and not update Colorconverter?");
                    if (member != null) {
                        return new InstanceDescriptor(member, args);
                    } 
                    else {
                        return null; 
                    } 
                }
            } 

            return base.ConvertTo(context, culture, value, destinationType);
        }
 
        /// 
        ///  
        ///      Fills the given hashtable with field name / value pairs.  It walks all public static 
        ///      properties of enumType that have a property type of Color.
        ///  
        private static void FillConstants(Hashtable hash, Type enumType) {
            MethodAttributes attrs = MethodAttributes.Public | MethodAttributes.Static;
            PropertyInfo[] props = enumType.GetProperties();
 
            for (int i = 0; i < props.Length; i++) {
                PropertyInfo prop = props[i]; 
                if (prop.PropertyType == typeof(Color)) { 
                    MethodInfo method = prop.GetGetMethod();
                    if (method != null && (method.Attributes & attrs) == attrs) { 
                        object[] tempIndex = null;
                        hash[prop.Name] = prop.GetValue(null, tempIndex);
                    }
                } 
            }
        } 
 
        /// 
        ///  
        ///      Retrieves a collection containing a set of standard values
        ///      for the data type this validator is designed for.  This
        ///      will return null if the data type does not support a
        ///      standard set of values. 
        /// 
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) { 
            if (values == null) { 
                lock (ValuesLock) {
                    if (values == null) { 

                       // We must take the value from each hashtable and combine them.
                       //
                       ArrayList arrayValues = new ArrayList(); 
                       arrayValues.AddRange(Colors.Values);
                       arrayValues.AddRange(SystemColors.Values); 
 
                       // Now, we have a couple of colors that have the same names but
                       // are identical values.  Look for these and remove them.  Too 
                       // bad this is n^2.
                       //
                       int count = arrayValues.Count;
                       for (int i = 0; i < count - 1; i++) { 
                           for (int j = i + 1; j < count; j++) {
                               if (arrayValues[i].Equals(arrayValues[j])) { 
                                   // Remove this item! 
                                   //
                                   arrayValues.RemoveAt(j); 
                                   count--;
                                   j--;
                               }
                           } 
                       }
 
                       // Sort the array. 
                       //
                       arrayValues.Sort(0, arrayValues.Count, new ColorComparer()); 
                       values = new StandardValuesCollection(arrayValues.ToArray());
                    }
                }
            } 

            return values; 
        } 

        ///  
        /// 
        ///      Determines if this object supports a standard set of values
        ///      that can be picked from a list.
        ///  
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context) {
            return true; 
        } 

        ///  
        /// 
        ///      IComparer for color values.  This takes color values but compares their
        ///      names.
        ///  
        private class ColorComparer : IComparer {
 
            public int Compare(object left, object right) { 
                Color cLeft = (Color)left;
                Color cRight = (Color)right; 
                return string.Compare(cLeft.Name, cRight.Name, false, CultureInfo.InvariantCulture);
            }
        }
    } 
}
 
 


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

/* 
 */ 
namespace System.Drawing {
    using System.Runtime.Serialization.Formatters; 
    using System.Runtime.InteropServices;
    using System.Diagnostics;
    using System.Diagnostics.CodeAnalysis;
    using Microsoft.Win32; 
    using System.Collections;
    using System.ComponentModel; 
    using System.ComponentModel.Design.Serialization; 
    using System.Globalization;
    using System.Reflection; 
    using System.Threading;

    /// 
    ///  
    ///      ColorConverter is a class that can be used to convert
    ///      colors from one data type to another.  Access this 
    ///      class through the TypeDescriptor. 
    /// 
    public class ColorConverter : TypeConverter { 
        private static string ColorConstantsLock = "colorConstants";
        private static Hashtable colorConstants;
        private static string SystemColorConstantsLock = "systemColorConstants";
        private static Hashtable systemColorConstants; 
        private static string ValuesLock = "values";
        private static StandardValuesCollection values; 
 
        /// 
        ///  
        ///    [To be supplied.]
        /// 
        public ColorConverter() {
        } 

        ///  
        ///  
        ///      Hashtable of color / value pairs (color name is key)
        ///      for standard colors. 
        /// 
        private static Hashtable Colors {
            get {
                if (colorConstants == null) { 
                    lock(ColorConstantsLock) {
                        if (colorConstants == null) { 
                            Hashtable tempHash = new Hashtable(StringComparer.OrdinalIgnoreCase); 
                            FillConstants(tempHash, typeof(Color));
                            colorConstants = tempHash; 
                        }
                    }
                }
 
                return colorConstants;
            } 
        } 

        ///  
        /// 
        ///      Hashtable of color / value pairs (color name is key)
        ///      for system colors.
        ///  
        private static Hashtable SystemColors {
            get { 
                if (systemColorConstants == null) { 
                    lock (SystemColorConstantsLock) {
                        if (systemColorConstants == null) { 
                            Hashtable tempHash = new Hashtable(StringComparer.OrdinalIgnoreCase);
                            FillConstants(tempHash, typeof(System.Drawing.SystemColors));
                            systemColorConstants = tempHash;
                        } 
                    }
                } 
 
                return systemColorConstants;
            } 
        }

        /// 
        ///  
        ///      Determines if this converter can convert an object in the given source
        ///      type to the native type of the converter. 
        ///  
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
            if (sourceType == typeof(string)) { 
                return true;
            }
            return base.CanConvertFrom(context, sourceType);
        } 

        ///  
        ///  
        ///    Gets a value indicating whether this converter can
        ///       convert an object to the given destination type using the context. 
        /// 
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) {
            if (destinationType == typeof(InstanceDescriptor)) {
                return true; 
            }
            return base.CanConvertTo(context, destinationType); 
        } 

        internal static object GetNamedColor(string name) { 
            object color = null;
            // First, check to see if this is a standard name.
            //
            color = Colors[name]; 
            if (color != null) {
                return color; 
            } 
            // Ok, how about a system color?
            // 
            color = SystemColors[name];
            return color;
        }
 
        /// 
        ///  
        ///      Converts the given object to the converter's native type. 
        /// 
        [SuppressMessage("Microsoft.Performance", "CA1808:AvoidCallsThatBoxValueTypes")] 
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
            string strValue = value as string;
            if (strValue != null) {
                object obj = null; 
                string text = strValue.Trim();
 
                if (text.Length == 0) { 
                    obj = Color.Empty;
                } 
                else {
                    // First, check to see if this is a standard name.
                    //
                    obj = GetNamedColor(text); 

                    if (obj == null) { 
                        if (culture == null) { 
                            culture = CultureInfo.CurrentCulture;
                        } 

                        char sep = culture.TextInfo.ListSeparator[0];
                        bool tryMappingToKnownColor = true;
 
                        TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
 
                        // If the value is a 6 digit hex number only, then 
                        // we want to treat the Alpha as 255, not 0
                        // 
                        if (text.IndexOf(sep) == -1) {

                            // text can be '' (empty quoted string)
                            if (text.Length >= 2 && (text[0] == '\'' || text[0] == '"') && text[0] == text[text.Length -1]) { 
                                // In quotes means a named value
                                string colorName = text.Substring(1, text.Length - 2); 
                                obj = Color.FromName(colorName); 
                                tryMappingToKnownColor = false;
                            } 
                            else if ((text.Length == 7 && text[0] == '#') ||
                                     (text.Length == 8 && (text.StartsWith("0x") || text.StartsWith("0X"))) ||
                                     (text.Length == 8 && (text.StartsWith("&h") || text.StartsWith("&H")))) {
                                // Note: ConvertFromString will raise exception if value cannot be converted. 
                                obj = Color.FromArgb(unchecked((int)(0xFF000000 | (uint)(int)intConverter.ConvertFromString(context, culture, text))));
                            } 
                        } 

                        // Nope.  Parse the RGBA from the text. 
                        //
                        if (obj == null) {
                            string[] tokens = text.Split(new char[] {sep});
                            int[] values = new int[tokens.Length]; 
                            for (int i = 0; i < values.Length; i++) {
                                values[i] = (int)intConverter.ConvertFromString(context, culture, tokens[i]); 
                            } 

                            // We should now have a number of parsed integer values. 
                            // We support 1, 3, or 4 arguments:
                            //
                            // 1 -- full ARGB encoded
                            // 3 -- RGB 
                            // 4 -- ARGB
                            // 
                            switch (values.Length) { 
                                case 1:
                                    obj = Color.FromArgb(values[0]); 
                                    break;

                                case 3:
                                    obj = Color.FromArgb(values[0], values[1], values[2]); 
                                    break;
 
                                case 4: 
                                    obj = Color.FromArgb(values[0], values[1], values[2], values[3]);
                                    break; 
                            }
                            tryMappingToKnownColor = true;
                        }
 
                        if ((obj != null) && tryMappingToKnownColor) {
 
                            // Now check to see if this color matches one of our known colors. 
                            // If it does, then substitute it.  We can only do this for "Colors"
                            // because system colors morph with user settings. 
                            //
                            int targetARGB = ((Color)obj).ToArgb();

                            foreach (Color c in Colors.Values) { 
                                if (c.ToArgb() == targetARGB) {
                                    obj = c; 
                                    break; 
                                }
                            } 
                        }
                    }

                    if (obj == null) { 
                        throw new ArgumentException(SR.GetString(SR.InvalidColor, text));
                    } 
                } 
                return obj;
            } 
            return base.ConvertFrom(context, culture, value);
        }

        ///  
        /// 
        ///      Converts the given object to another type.  The most common types to convert 
        ///      are to and from a string object.  The default implementation will make a call 
        ///      to ToString on the object if the object is valid and if the destination
        ///      type is string.  If this cannot convert to the desitnation type, this will 
        ///      throw a NotSupportedException.
        /// 
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
            if (destinationType == null) { 
                throw new ArgumentNullException("destinationType");
            } 
 
            if( value is Color ){
                if (destinationType == typeof(string)) { 
                    Color c = (Color)value;

                    if (c == Color.Empty) {
                        return string.Empty; 
                    }
                    else { 
                        // If this is a known color, then Color can provide its own 
                        // name.  Otherwise, we fabricate an ARGB value for it.
                        // 
                        if (c.IsKnownColor) {
                            return c.Name;
                        }
                        else if (c.IsNamedColor) { 
                            return "'" + c.Name + "'";
                        } 
                        else { 
                            if (culture == null) {
                                culture = CultureInfo.CurrentCulture; 
                            }
                            string sep = culture.TextInfo.ListSeparator + " ";
                            TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
                            string[] args; 
                            int nArg = 0;
 
                            if (c.A < 255) { 
                                args = new string[4];
                                args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.A); 
                            }
                            else {
                                args = new string[3];
                            } 

                            // Note: ConvertToString will raise exception if value cannot be converted. 
                            args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.R); 
                            args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.G);
                            args[nArg++] = intConverter.ConvertToString(context, culture, (object)c.B); 

                            // Now slam all of these together with the fantastic Join
                            // method.
                            // 
                            return string.Join(sep, args);
                        } 
                    } 
                }
                if (destinationType == typeof(InstanceDescriptor)) { 
                    MemberInfo member = null;
                    object[] args = null;

                    Color c = (Color)value; 

                    if (c.IsEmpty) { 
                        member = typeof(Color).GetField("Empty"); 
                    }
                    else if (c.IsSystemColor) { 
                        member = typeof(SystemColors).GetProperty(c.Name);
                    }
                    else if (c.IsKnownColor) {
                        member = typeof(Color).GetProperty(c.Name); 
                    }
                    else if (c.A != 255) { 
                        member = typeof(Color).GetMethod("FromArgb", new Type[] {typeof(int), typeof(int), typeof(int), typeof(int)}); 
                        args = new object[] {c.A, c.R, c.G, c.B};
                    } 
                    else if (c.IsNamedColor) {
                        member = typeof(Color).GetMethod("FromName", new Type[] {typeof(string)});
                        args = new object[] {c.Name};
                    } 
                    else {
                        member = typeof(Color).GetMethod("FromArgb", new Type[] {typeof(int), typeof(int), typeof(int)}); 
                        args = new object[] {c.R, c.G, c.B}; 
                    }
 
                    Debug.Assert(member != null, "Could not convert color to member.  Did someone change method name / signature and not update Colorconverter?");
                    if (member != null) {
                        return new InstanceDescriptor(member, args);
                    } 
                    else {
                        return null; 
                    } 
                }
            } 

            return base.ConvertTo(context, culture, value, destinationType);
        }
 
        /// 
        ///  
        ///      Fills the given hashtable with field name / value pairs.  It walks all public static 
        ///      properties of enumType that have a property type of Color.
        ///  
        private static void FillConstants(Hashtable hash, Type enumType) {
            MethodAttributes attrs = MethodAttributes.Public | MethodAttributes.Static;
            PropertyInfo[] props = enumType.GetProperties();
 
            for (int i = 0; i < props.Length; i++) {
                PropertyInfo prop = props[i]; 
                if (prop.PropertyType == typeof(Color)) { 
                    MethodInfo method = prop.GetGetMethod();
                    if (method != null && (method.Attributes & attrs) == attrs) { 
                        object[] tempIndex = null;
                        hash[prop.Name] = prop.GetValue(null, tempIndex);
                    }
                } 
            }
        } 
 
        /// 
        ///  
        ///      Retrieves a collection containing a set of standard values
        ///      for the data type this validator is designed for.  This
        ///      will return null if the data type does not support a
        ///      standard set of values. 
        /// 
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) { 
            if (values == null) { 
                lock (ValuesLock) {
                    if (values == null) { 

                       // We must take the value from each hashtable and combine them.
                       //
                       ArrayList arrayValues = new ArrayList(); 
                       arrayValues.AddRange(Colors.Values);
                       arrayValues.AddRange(SystemColors.Values); 
 
                       // Now, we have a couple of colors that have the same names but
                       // are identical values.  Look for these and remove them.  Too 
                       // bad this is n^2.
                       //
                       int count = arrayValues.Count;
                       for (int i = 0; i < count - 1; i++) { 
                           for (int j = i + 1; j < count; j++) {
                               if (arrayValues[i].Equals(arrayValues[j])) { 
                                   // Remove this item! 
                                   //
                                   arrayValues.RemoveAt(j); 
                                   count--;
                                   j--;
                               }
                           } 
                       }
 
                       // Sort the array. 
                       //
                       arrayValues.Sort(0, arrayValues.Count, new ColorComparer()); 
                       values = new StandardValuesCollection(arrayValues.ToArray());
                    }
                }
            } 

            return values; 
        } 

        ///  
        /// 
        ///      Determines if this object supports a standard set of values
        ///      that can be picked from a list.
        ///  
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context) {
            return true; 
        } 

        ///  
        /// 
        ///      IComparer for color values.  This takes color values but compares their
        ///      names.
        ///  
        private class ColorComparer : IComparer {
 
            public int Compare(object left, object right) { 
                Color cLeft = (Color)left;
                Color cRight = (Color)right; 
                return string.Compare(cLeft.Name, cRight.Name, false, CultureInfo.InvariantCulture);
            }
        }
    } 
}
 
 


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

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