/
ReferenceTypeConverter.cs
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/
ReferenceTypeConverter.cs
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#nullable disable
using System;
using System.ComponentModel;
using System.Globalization;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Maui.Controls.Internals;
using Microsoft.Maui.Controls.Xaml;
using Microsoft.Maui.Controls.Xaml.Internals;
namespace Microsoft.Maui.Controls
{
/// <include file="../../docs/Microsoft.Maui.Controls/ReferenceTypeConverter.xml" path="Type[@FullName='Microsoft.Maui.Controls.ReferenceTypeConverter']/Docs/*" />
[RequireService([typeof(IReferenceProvider), typeof(IProvideParentValues)])]
public sealed class ReferenceTypeConverter : TypeConverter, IExtendedTypeConverter
{
public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
=> sourceType == typeof(string);
public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
=> destinationType == typeof(string);
object IExtendedTypeConverter.ConvertFromInvariantString(string value, IServiceProvider serviceProvider)
{
if (serviceProvider == null)
throw new ArgumentNullException(nameof(serviceProvider));
var referenceProvider = serviceProvider.GetService<IReferenceProvider>();
if (referenceProvider != null)
return referenceProvider.FindByName(value) ?? throw new XamlParseException($"Can't resolve name '{value}' on Element", serviceProvider);
if (!(serviceProvider.GetService(typeof(IProvideValueTarget)) is IProvideParentValues valueProvider))
throw new ArgumentException("serviceProvider does not provide an IProvideValueTarget");
foreach (var target in valueProvider.ParentObjects)
{
if (!(target is INameScope ns))
continue;
var element = ns.FindByName(value);
if (element != null)
return element;
}
throw new Exception("Can't resolve name on Element");
}
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
=> throw new NotImplementedException();
public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
=> throw new NotSupportedException();
}
}