EnumConverter.cs

using System.Collections;
using System.Collections.Generic;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
using System.Reflection;
using System.Security.Permissions;

namespace System.ComponentModel
{
    [HostProtection(SecurityAction.LinkDemand, SharedState = true)]
    public class EnumConverter : TypeConverter
    {
        private StandardValuesCollection values;

        private Type type;

        protected Type EnumType => type;

        protected StandardValuesCollection Values
        {
            get
            {
                return values;
            }
            set
            {
                values = value;
            }
        }

        protected virtual IComparer Comparer => System.InvariantComparer.Default;

        public EnumConverter(Type type)
        {
            this.type = type;
        }

        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            if (sourceType == typeof(string) || sourceType == typeof(Enum[]))
            {
                return true;
            }
            return base.CanConvertFrom(context, sourceType);
        }

        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(InstanceDescriptor) || destinationType == typeof(Enum[]))
            {
                return true;
            }
            return base.CanConvertTo(context, destinationType);
        }

        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            if (value is string)
            {
                try
                {
                    string text = (string)value;
                    if (text.IndexOf(',') != -1)
                    {
                        long num = 0L;
                        string[] array = text.Split(',');
                        string[] array2 = array;
                        foreach (string value2 in array2)
                        {
                            num |= Convert.ToInt64((Enum)Enum.Parse(type, value2, ignoreCase: true), culture);
                        }
                        return Enum.ToObject(type, num);
                    }
                    return Enum.Parse(type, text, ignoreCase: true);
                }
                catch (Exception innerException)
                {
                    throw new FormatException(SR.GetString("ConvertInvalidPrimitive", (string)value, type.Name), innerException);
                }
            }
            if (value is Enum[])
            {
                long num2 = 0L;
                Enum[] array3 = (Enum[])value;
                foreach (Enum value3 in array3)
                {
                    num2 |= Convert.ToInt64(value3, culture);
                }
                return Enum.ToObject(type, num2);
            }
            return base.ConvertFrom(context, culture, value);
        }

        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType == null)
            {
                throw new ArgumentNullException("destinationType");
            }
            if (destinationType == typeof(string) && value != null)
            {
                Type underlyingType = Enum.GetUnderlyingType(type);
                if (value is IConvertible && value.GetType() != underlyingType)
                {
                    value = ((IConvertible)value).ToType(underlyingType, culture);
                }
                if (!type.IsDefined(typeof(FlagsAttribute), inherit: false) && !Enum.IsDefined(type, value))
                {
                    throw new ArgumentException(SR.GetString("EnumConverterInvalidValue", value.ToString(), type.Name));
                }
                return Enum.Format(type, value, "G");
            }
            if (destinationType == typeof(InstanceDescriptor) && value != null)
            {
                string text = ConvertToInvariantString(context, value);
                if (type.IsDefined(typeof(FlagsAttribute), inherit: false) && text.IndexOf(',') != -1)
                {
                    Type underlyingType2 = Enum.GetUnderlyingType(type);
                    if (value is IConvertible)
                    {
                        object obj = ((IConvertible)value).ToType(underlyingType2, culture);
                        MethodInfo method = typeof(Enum).GetMethod("ToObject", new Type[2]
                        {
                            typeof(Type),
                            underlyingType2
                        });
                        if (method != null)
                        {
                            return new InstanceDescriptor(method, new object[2]
                            {
                                type,
                                obj
                            });
                        }
                    }
                }
                else
                {
                    FieldInfo field = type.GetField(text);
                    if (field != null)
                    {
                        return new InstanceDescriptor(field, null);
                    }
                }
            }
            if (destinationType == typeof(Enum[]) && value != null)
            {
                if (type.IsDefined(typeof(FlagsAttribute), inherit: false))
                {
                    List<Enum> list = new List<Enum>();
                    Array array = Enum.GetValues(type);
                    long[] array2 = new long[array.Length];
                    for (int i = 0; i < array.Length; i++)
                    {
                        array2[i] = Convert.ToInt64((Enum)array.GetValue(i), culture);
                    }
                    long num = Convert.ToInt64((Enum)value, culture);
                    bool flag = true;
                    while (flag)
                    {
                        flag = false;
                        long[] array3 = array2;
                        foreach (long num2 in array3)
                        {
                            if ((num2 != 0L && (num2 & num) == num2) || num2 == num)
                            {
                                list.Add((Enum)Enum.ToObject(type, num2));
                                flag = true;
                                num &= ~num2;
                                break;
                            }
                        }
                        if (num == 0L)
                        {
                            break;
                        }
                    }
                    if (!flag && num != 0L)
                    {
                        list.Add((Enum)Enum.ToObject(type, num));
                    }
                    return list.ToArray();
                }
                return new Enum[1]
                {
                    (Enum)Enum.ToObject(type, value)
                };
            }
            return base.ConvertTo(context, culture, value, destinationType);
        }

        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
        {
            if (values == null)
            {
                Type reflectionType = TypeDescriptor.GetReflectionType(type);
                if (reflectionType == null)
                {
                    reflectionType = type;
                }
                FieldInfo[] fields = reflectionType.GetFields(BindingFlags.Static | BindingFlags.Public);
                ArrayList arrayList = null;
                if (fields != null && fields.Length != 0)
                {
                    arrayList = new ArrayList(fields.Length);
                }
                if (arrayList != null)
                {
                    FieldInfo[] array = fields;
                    foreach (FieldInfo fieldInfo in array)
                    {
                        BrowsableAttribute browsableAttribute = null;
                        object[] customAttributes = fieldInfo.GetCustomAttributes(typeof(BrowsableAttribute), inherit: false);
                        for (int j = 0; j < customAttributes.Length; j++)
                        {
                            Attribute attribute = (Attribute)customAttributes[j];
                            browsableAttribute = (attribute as BrowsableAttribute);
                        }
                        if (browsableAttribute == null || browsableAttribute.Browsable)
                        {
                            object obj = null;
                            try
                            {
                                if (fieldInfo.Name != null)
                                {
                                    obj = Enum.Parse(type, fieldInfo.Name);
                                }
                            }
                            catch (ArgumentException)
                            {
                            }
                            if (obj != null)
                            {
                                arrayList.Add(obj);
                            }
                        }
                    }
                    IComparer comparer = Comparer;
                    if (comparer != null)
                    {
                        arrayList.Sort(comparer);
                    }
                }
                Array array2 = arrayList?.ToArray();
                values = new StandardValuesCollection(array2);
            }
            return values;
        }

        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
        {
            return !type.IsDefined(typeof(FlagsAttribute), inherit: false);
        }

        public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
        {
            return true;
        }

        public override bool IsValid(ITypeDescriptorContext context, object value)
        {
            return Enum.IsDefined(type, value);
        }
    }
}