TypeListConverter.cs

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using System.ComponentModel.Design.Serialization;
using System.Globalization;
 
namespace System.ComponentModel;
 
public abstract class TypeListConverter : TypeConverter
{
    private readonly Type[] _types;
 
    private StandardValuesCollection _values;
 
    protected TypeListConverter(Type[] types)
    {
        _types = types;
    }
 
    public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
    {
        if (!(sourceType == typeof(string)))
        {
            return base.CanConvertFrom(context, sourceType);
        }
        return true;
    }
 
    public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destinationType)
    {
        if (!(destinationType == typeof(InstanceDescriptor)))
        {
            return base.CanConvertTo(context, destinationType);
        }
        return true;
    }
 
    public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
    {
        if (value is string)
        {
            Type[] types = _types;
            foreach (Type type in types)
            {
                if (value.Equals(type.FullName))
                {
                    return type;
                }
            }
        }
        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))
        {
            if (value == null)
            {
                return System.SR.none;
            }
            return ((Type)value).FullName;
        }
        return base.ConvertTo(context, culture, value, destinationType);
    }
 
    public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext? context)
    {
        if (_values == null)
        {
            object[] array;
            if (_types != null)
            {
                array = new object[_types.Length];
                Array.Copy(_types, array, _types.Length);
            }
            else
            {
                array = null;
            }
            _values = new StandardValuesCollection(array);
        }
        return _values;
    }
 
    public override bool GetStandardValuesExclusive(ITypeDescriptorContext? context)
    {
        return true;
    }
 
    public override bool GetStandardValuesSupported(ITypeDescriptorContext? context)
    {
        return true;
    }
}