|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
namespace System.Windows.Forms;
public partial struct LinkArea
{
/// <summary>
/// LinkAreaConverter is a class that can be used to convert LinkArea from one data type
/// to another. Access this class through the TypeDescriptor.
/// </summary>
public class LinkAreaConverter : TypeConverter
{
/// <summary>
/// Determines if this converter can convert an object in the given source
/// type to the native type of the converter.
/// </summary>
public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
{
if (sourceType == typeof(string))
{
return true;
}
return 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, Type? destinationType)
{
if (destinationType == typeof(InstanceDescriptor))
{
return true;
}
return base.CanConvertTo(context, destinationType);
}
/// <summary>
/// Converts the given object to the converter's native type.
/// </summary>
public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
{
if (value is string valueStr)
{
ReadOnlySpan<char> text = valueStr.AsSpan().Trim();
if (text.IsEmpty)
{
return null;
}
// Parse 2 integer values.
culture ??= CultureInfo.CurrentCulture;
Span<int> values = stackalloc int[2];
if (!TypeConverterHelper.TryParseAsSpan(context, culture, text, values))
{
throw new ArgumentException(
string.Format(
SR.TextParseFailedFormat,
valueStr,
"start, length"));
}
return new LinkArea(values[0], values[1]);
}
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 (value is LinkArea pt)
{
if (destinationType == typeof(string))
{
culture ??= CultureInfo.CurrentCulture;
string sep = culture.TextInfo.ListSeparator + " ";
TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
string?[] args =
[
intConverter.ConvertToString(context, culture, pt.Start),
intConverter.ConvertToString(context, culture, pt.Length)
];
return string.Join(sep, args);
}
else if (destinationType == typeof(InstanceDescriptor))
{
return new InstanceDescriptor(
typeof(LinkArea).GetConstructor([typeof(int), typeof(int)]),
new object[] { pt.Start, pt.Length });
}
}
return base.ConvertTo(context, culture, value, destinationType);
}
/// <summary>
/// Creates an instance of this type given a set of property values
/// for the object. This is useful for objects that are immutable, but still
/// want to provide changeable properties.
/// </summary>
public override object CreateInstance(ITypeDescriptorContext? context, IDictionary propertyValues)
{
ArgumentNullException.ThrowIfNull(propertyValues);
try
{
return new LinkArea(
(int)propertyValues[nameof(Start)]!,
(int)propertyValues[nameof(Length)]!);
}
catch (InvalidCastException invalidCast)
{
throw new ArgumentException(SR.PropertyValueInvalidEntry, nameof(propertyValues), invalidCast);
}
catch (NullReferenceException nullRef)
{
throw new ArgumentException(SR.PropertyValueInvalidEntry, nameof(propertyValues), nullRef);
}
}
/// <summary>
/// Determines if changing a value on this object should require a call to
/// CreateInstance to create a new value.
/// </summary>
public override bool GetCreateInstanceSupported(ITypeDescriptorContext? context) => true;
/// <summary>
/// Retrieves the set of properties for this type. By default, a type has
/// does not return any properties. An easy implementation of this method
/// can just call TypeDescriptor.GetProperties for the correct data type.
/// </summary>
[RequiresUnreferencedCode(TrimmingConstants.TypeConverterGetPropertiesMessage)]
public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext? context, object value, Attribute[]? attributes)
{
PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(LinkArea), attributes);
return props.Sort([nameof(Start), nameof(Length)]);
}
/// <summary>
/// Determines if this object supports properties. By default, this is false.
/// </summary>
public override bool GetPropertiesSupported(ITypeDescriptorContext? context) => true;
}
}
|