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//------------------------------------------------------------------------------
// <copyright file="CustomTypeDescriptor.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.ComponentModel
{
using System;
using System.Security.Permissions;
/// <devdoc>
/// </devdoc>
[HostProtection(SharedState = true)]
public abstract class CustomTypeDescriptor : ICustomTypeDescriptor
{
private ICustomTypeDescriptor _parent;
/// <devdoc>
/// Creates a new CustomTypeDescriptor object. There are two versions
/// of this constructor. The version that takes no parameters simply
/// calls the version that takes a parent and passes null as the
/// parent value. If the parent is null, CustomTypeDescriptor returns
/// the defined default values for each method. If the parent is
/// non-null, CustomTypeDescriptor calls the parent's version of
/// the method.
/// </devdoc>
protected CustomTypeDescriptor()
{
}
/// <devdoc>
/// Creates a new CustomTypeDescriptor object. There are two versions
/// of this constructor. The version that takes no parameters simply
/// calls the version that takes a parent and passes null as the
/// parent value. If the parent is null, CustomTypeDescriptor returns
/// the defined default values for each method. If the parent is
/// non-null, CustomTypeDescriptor calls the parent's version of
/// the method.
/// </devdoc>
protected CustomTypeDescriptor(ICustomTypeDescriptor parent)
{
_parent = parent;
}
/// <devdoc>
/// The GetAttributes method returns the type-level attributes for
/// the type this custom type descriptor is providing information for.
/// You must always return a valid collection from this method.
/// </devdoc>
public virtual AttributeCollection GetAttributes()
{
if (_parent != null)
{
return _parent.GetAttributes();
}
return AttributeCollection.Empty;
}
/// <devdoc>
/// The GetClassName method returns the fully qualified name of the
/// class this type descriptor is representing. Returning null from
/// this method causes the TypeDescriptor object to return the
/// default class name.
/// </devdoc>
public virtual string GetClassName()
{
if (_parent != null)
{
return _parent.GetClassName();
}
return null;
}
/// <devdoc>
/// The GetComponentName method returns the name of the component instance
/// this type descriptor is describing.
/// </devdoc>
public virtual string GetComponentName()
{
if (_parent != null)
{
return _parent.GetComponentName();
}
return null;
}
/// <devdoc>
/// The GetConverter method returns a type converter for the type this type
/// descriptor is representing.
/// </devdoc>
public virtual TypeConverter GetConverter()
{
if (_parent != null)
{
return _parent.GetConverter();
}
return new TypeConverter();
}
/// <devdoc>
/// The GetDefaultEvent method returns the event descriptor for the default
/// event on the object this type descriptor is representing.
/// </devdoc>
public virtual EventDescriptor GetDefaultEvent()
{
if (_parent != null)
{
return _parent.GetDefaultEvent();
}
return null;
}
/// <devdoc>
/// The GetDefaultProperty method returns the property descriptor for the
/// default property on the object this type descriptor is representing.
/// </devdoc>
public virtual PropertyDescriptor GetDefaultProperty()
{
if (_parent != null)
{
return _parent.GetDefaultProperty();
}
return null;
}
/// <devdoc>
/// The GetEditor method returns an editor of the given type that is
/// to be associated with the class this type descriptor is representing.
/// </devdoc>
public virtual object GetEditor(Type editorBaseType)
{
if (_parent != null)
{
return _parent.GetEditor(editorBaseType);
}
return null;
}
/// <devdoc>
/// The GetEvents method returns a collection of event descriptors
/// for the object this type descriptor is representing. An optional
/// attribute array may be provided to filter the collection that is
/// returned. If no parent is provided,this will return an empty
/// event collection.
/// </devdoc>
public virtual EventDescriptorCollection GetEvents()
{
if (_parent != null)
{
return _parent.GetEvents();
}
return EventDescriptorCollection.Empty;
}
/// <devdoc>
/// The GetEvents method returns a collection of event descriptors
/// for the object this type descriptor is representing. An optional
/// attribute array may be provided to filter the collection that is
/// returned. If no parent is provided,this will return an empty
/// event collection.
/// </devdoc>
public virtual EventDescriptorCollection GetEvents(Attribute[] attributes)
{
if (_parent != null)
{
return _parent.GetEvents(attributes);
}
return EventDescriptorCollection.Empty;
}
/// <devdoc>
/// The GetProperties method returns a collection of property descriptors
/// for the object this type descriptor is representing. An optional
/// attribute array may be provided to filter the collection that is returned.
/// If no parent is provided,this will return an empty
/// property collection.
/// </devdoc>
public virtual PropertyDescriptorCollection GetProperties()
{
if (_parent != null)
{
return _parent.GetProperties();
}
return PropertyDescriptorCollection.Empty;
}
/// <devdoc>
/// The GetProperties method returns a collection of property descriptors
/// for the object this type descriptor is representing. An optional
/// attribute array may be provided to filter the collection that is returned.
/// If no parent is provided,this will return an empty
/// property collection.
/// </devdoc>
public virtual PropertyDescriptorCollection GetProperties(Attribute[] attributes)
{
if (_parent != null)
{
return _parent.GetProperties(attributes);
}
return PropertyDescriptorCollection.Empty;
}
/// <devdoc>
/// The GetPropertyOwner method returns an instance of an object that
/// owns the given property for the object this type descriptor is representing.
/// An optional attribute array may be provided to filter the collection that is
/// returned. Returning null from this method causes the TypeDescriptor object
/// to use its default type description services.
/// </devdoc>
public virtual object GetPropertyOwner(PropertyDescriptor pd)
{
if (_parent != null)
{
return _parent.GetPropertyOwner(pd);
}
return null;
}
}
}
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