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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.ComponentModel;
using System.Globalization;
using System.Reflection;
using System.Xaml;
namespace System.Windows.Markup
{
/// <summary>
/// Type converter for RoutedEvent type
/// </summary>
public sealed class EventSetterHandlerConverter : TypeConverter
{
static Type s_ServiceProviderContextType;
/// <summary>
/// Whether we can convert from a given type - this class only converts from string
/// </summary>
public override bool CanConvertFrom(ITypeDescriptorContext typeDescriptorContext, Type sourceType)
{
// We can only convert from a string and that too only if we have all the contextual information
// Note: Sometimes even the serializer calls CanConvertFrom in order
// to determine if it is a valid converter to use for serialization.
if (sourceType == typeof(string))
{
return true;
}
return false;
}
/// <summary>
/// Whether we can convert to a given type - this class only converts to string
/// </summary>
public override bool CanConvertTo(ITypeDescriptorContext typeDescriptorContext, Type destinationType)
{
return false;
}
/// <summary>
/// Convert a string like "Button.Click" into the corresponding RoutedEvent
/// </summary>
public override object ConvertFrom(ITypeDescriptorContext typeDescriptorContext,
CultureInfo cultureInfo,
object source)
{
ArgumentNullException.ThrowIfNull(typeDescriptorContext);
ArgumentNullException.ThrowIfNull(source);
if (s_ServiceProviderContextType == null)
{
// get typeof(MS.Internal.Xaml.ServiceProviderContext) via reflection
Assembly a = typeof(IRootObjectProvider).Assembly;
s_ServiceProviderContextType = a.GetType("MS.Internal.Xaml.ServiceProviderContext");
}
if (typeDescriptorContext.GetType() != s_ServiceProviderContextType)
{
// if the caller is not the XAML parser, don't answer. This avoids
// returning an arbitrary delegate to a (possibly malicious) caller.
throw new ArgumentException(SR.TextRange_InvalidParameterValue, "typeDescriptorContext");
}
IRootObjectProvider rootProvider = typeDescriptorContext.GetService(typeof(IRootObjectProvider)) as IRootObjectProvider;
if (rootProvider != null && source is String)
{
IProvideValueTarget ipvt = typeDescriptorContext.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
if (ipvt != null)
{
EventSetter setter = ipvt.TargetObject as EventSetter;
string handlerName;
if(setter != null && (handlerName = source as string) != null)
{
handlerName = handlerName.Trim();
return Delegate.CreateDelegate(setter.Event.HandlerType, rootProvider.RootObject, handlerName);
}
}
}
throw GetConvertFromException(source);
}
/// <summary>
/// Convert a RoutedEventID into a XAML string like "Button.Click"
/// </summary>
public override object ConvertTo(ITypeDescriptorContext typeDescriptorContext,
CultureInfo cultureInfo,
object value,
Type destinationType)
{
throw GetConvertToException(value, destinationType);
}
}
}
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