Is Silverlight's DataAnnotations a Subset of .NET's? : Silverlight Feeds

Is Silverlight's DataAnnotations a Subset of .NET's?

by Jeff Handley via Jeff Handley on 11/16/2010 9:39:49 PM

I was one of the developers that ported the System.ComponentModel.DataAnnotations assembly to Silverlight. Every once in awhile, someone asks me if the Silverlight version of the assembly is a subset of what is in .NET. The answer is Yes, but there are some caveats, and I’m honestly tired of regurgitating the detailed answer. With this blog post in place, I can now simply point people to a URL for the answer. This is what we call DRY.

I’m sure that it goes without saying that the implementation details of the two assemblies differ. In the .NET version, we have TypeDescriptor at our disposal, and it’s used to gather metadata about types and members. In Silverlight, TypeDescriptor doesn’t exist, so raw Reflection is used in its place. Moreover, .NET offers the MetadataTypeAttribute to allow metadata to be loaded from another type--Silverlight doesn’t support that either, so again the implementations differ rather significantly. There are other reasons for implementation differences too, but it suffices to say that underneath the public API, the differences are manifold.

Public API Differences:

Type / Member	.NET	Silverlight	Notes
AssociatedMetadataTypeTypeDescriptionProvider	Yes	No
AssociationAttribute	Yes	Yes
AssociationAttribute.TypeId	Yes	No	Due to Attribute difference
ConcurrencyCheckAttribute	Yes	Yes
CustomValidationAttribute	Yes	Yes
CustomValidationAttribute.TypeId	Yes	No	Due to Attribute difference
DataType	Yes	Yes
DataTypeAttribute	Yes	Yes
DataTypeAttribute.IsValid(Object)	Yes	No	Internal in Silverlight
DisplayAttribute	Yes	Yes
DisplayColumnAttribute	Yes	Yes
DisplayColumnAttribute.HtmlEncode	Yes	No
EditableAttribute	Yes	Yes
EnumDataTypeAttribute	Yes	Yes
EnumDataTypeAttribute.IsValid(Object)	Yes	No	Internal in Silverlight
FilterUIHintAttribute	Yes	Yes
FilterUIHintAttribute.TypeId	Yes	No	Due to Attribute difference
IValidatableObject	Yes	No
KeyAttribute	Yes	Yes
MetadataTypeAttribute	Yes	No
RangeAttribute	Yes	Yes
RangeAttribute.IsValid(Object)	Yes	No	Internal in Silverlight
RegularExpressionAttribute	Yes	Yes
RegularExpressionAttribute.IsValid(Object)	Yes	No	Internal in Silverlight
RequiredAttribute	Yes	Yes
RequiredAttribute.IsValid(Object)	Yes	No	Internal in Silverlight
ScaffoldColumnAttribute	Yes	No
ScaffoldTableAttribute	Yes	No
StringLengthAttribute	Yes	Yes
StringLengthAttribute.IsValid(Object)	Yes	No	Internal in Silverlight
TimestampAttribute	Yes	Yes
UIHintAttribute	Yes	Yes
UIHintAttribute.TypeId	Yes	No	Due to Attribute difference
ValidationAttribute	Yes	Yes
ValidationAttribute.IsValid(Object)	Yes	No	Internal in Silverlight
ValidationAttribute.Validate(Object, String)	Yes	No
ValidationContext	Yes	Yes
ValidationContext.ServiceContainer	Yes	No
ValidationException	Yes	Yes
ValidationException.ctor(SerializationInfo, StreamingContext)	Yes	No
ValidationResult	Yes	Yes	Sealed in Silverlight, not in .NET
ValidationResult.ToString	Yes	No	Overridden in Silverlight, not in .NET
Validator	Yes	Yes