Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / 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; ////// /// public ColorConverter() { } ///[To be supplied.] ////// /// 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); } ////// /// 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; } ///Gets a value indicating whether this converter can /// convert an object to the given destination type using the context. ////// /// 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.
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