|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.ComponentModel.Design.Serialization;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Reflection;
namespace System.ComponentModel
{
/// <summary>
/// Provides a type converter to convert globally unique identifier objects to and from various
/// other representations.
/// </summary>
public class GuidConverter : TypeConverter
{
/// <summary>
/// Gets a value indicating whether this converter can convert an object in the given source
/// type to a globally unique identifier object using the context.
/// </summary>
public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
{
return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
}
/// <summary>
/// Gets a value indicating whether this converter can convert an object to
/// the given destination type using the context.
/// </summary>
public override bool CanConvertTo(ITypeDescriptorContext? context, [NotNullWhen(true)] Type? destinationType)
{
return destinationType == typeof(InstanceDescriptor) || base.CanConvertTo(context, destinationType);
}
/// <summary>
/// Converts the given object to a globally unique identifier object.
/// </summary>
public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
{
if (value is string text)
{
return new Guid(text);
}
return base.ConvertFrom(context, culture, value);
}
/// <summary>
/// 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 destination type, this will
/// throw a NotSupportedException.
/// </summary>
public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
{
if (destinationType == typeof(InstanceDescriptor) && value is Guid)
{
ConstructorInfo? ctor = typeof(Guid).GetConstructor(new Type[] { typeof(string) });
Debug.Assert(ctor != null, "Expected constructor to exist.");
return new InstanceDescriptor(ctor, new object?[] { value.ToString() });
}
return base.ConvertTo(context, culture, value, destinationType);
}
}
}
|