/// <summary>
/// Gets the <see cref="System.ComponentModel.TypeDescriptor"/> for the specified Type, using the specified parent descriptor
/// as the base. Overrides should call base to ensure the <see cref="System.ComponentModel.TypeDescriptor"/>s are chained properly.
/// </summary>
/// <param name="type">The Type to return a descriptor for.</param>
/// <param name="parent">The parent descriptor.</param>
/// <returns>The <see cref="System.ComponentModel.TypeDescriptor"/> for the specified Type.</returns>
public virtual ICustomTypeDescriptor GetTypeDescriptor(Type type, ICustomTypeDescriptor parent)
{
if (type == null)
{
throw Error.ArgumentNull("type");
}
if (parent == null)
{
throw Error.ArgumentNull("parent");
}
return(_parentProvider != null?_parentProvider.GetTypeDescriptor(type, parent) : parent);
}
public override ICustomTypeDescriptor GetTypeDescriptor(Type objectType, object instance)
{
if (objectType == null && instance != null)
{
objectType = instance.GetType();
}
if (_type != objectType)
{
// In inheritance scenarios, we might be called to provide a descriptor
// for a derived Type. In that case, we just return base.
return(base.GetTypeDescriptor(objectType, instance));
}
if (_customTypeDescriptor == null)
{
// CLR, buddy class type descriptors
_customTypeDescriptor = base.GetTypeDescriptor(objectType, instance);
// EF, any other custom type descriptors provided through MetadataProviders.
_customTypeDescriptor = _metadataProvider.GetTypeDescriptor(objectType, _customTypeDescriptor);
// initialize FK members AFTER our type descriptors have chained
var foreignKeyMembers = GetForeignKeyMembers();
// if any FK member of any association is also part of the primary key, then the key cannot be marked
// Editable(false)
var keyIsEditable = _customTypeDescriptor.GetProperties()
.Cast <PropertyDescriptor>()
.Where(pd => pd.Attributes[typeof(KeyAttribute)] != null)
.Any(pd => foreignKeyMembers.Contains(pd.Name));
if (DataControllerTypeDescriptor.ShouldRegister(_customTypeDescriptor, keyIsEditable, foreignKeyMembers))
{
// Extend the chain with one more descriptor.
_customTypeDescriptor = new DataControllerTypeDescriptor(_customTypeDescriptor, keyIsEditable, foreignKeyMembers);
}
}
return(_customTypeDescriptor);
}
