Fidget.Extensions.Reflection

Extensions and helpers for common reflection operations:

• Shallow-copies of entire instances.
• Shallow-copies of property values between instances.
• Property equality comparison.
• Minimize overhead imposed by reflection.

ReflectionComparer

An implementation of IEqualityComparer<T> that performs an equality comparison using property values (see the Equal method of IPropertyReflector below for how property values are compared).

TypeReflectorExtensions.Reflect

Returns an ITypeReflector<T> that provides access to reflected characteristics of a type. Currently, this is limited to the following methods:

• Clone - creates a shallow copy of the source object into a new instance.
• CopyTo - shallow-copies all writable public property values from one instance to another.

A note about the shallow copies: These operate almost identically to the Object.MemberwiseClone method:

If a field is a value type, a bit-by-bit copy of the field is performed. If a field is a reference type, the reference is copied but the referred object is not; therefore, the original object and its clone refer to the same object.

Arrays, however, are copied using the Array.Clone method, so that the resulting array can have its elements modified independently.

Additionally, ITypeReflector<T> is also a collection of IPropertyReflector<T> and includes a default property for accessing the collection by property name.

IPropertyReflector

Instances of IPropertyReflector<T> provide access to reflected characteristics of a property on its declaring type T.

• PropertyInfo - Reflected metadata for the property.
• Copy - Shallow-copies the property value from a source instance of the declaring type to a target instance (See note about shallow copies above).
• Equal - Returns whether the two property values are equal between two instances of the declaring type. This is done via Object.Equals except for arrays, which use IStructuralEquatable.Equals for a comparison of the array elements.

ModelReflectorExtensions.Model

Returns an IModelReflector<T> that provides attribute-driven property information useful for the construction of database statements. These are driven by the standard attributes found in System.ComponentModel.Annotations:

• NotMappedAttribute: Disregards the property.
• KeyAttribute: Indicates the property participates in the primary key.
• DatabaseGeneratedAttribute: Indicates whether the property is a database-generated value.
• ConcurrencyCheckAttribute: Indicates the property participates in concurrency checking.
• ColumnAttribute: Controls column position in their collections using the Order property. When the attribute is not present, they are sorted alphabetically.

IModelReflector<T> members:

• Table: Gets the table attribute on the model if one exists, otherwise null.
• Keys: Gets the collection of properties decorated by KeyAttribute.
• Generated: Gets the collection of properties decorated by DatabaseGeneratedAttribute with any option other than None.
• Concurrency: Gets the collection of properties decorated by ConcurrencyCheckAttribute.
• Selectable: Gets the collection of properties that are neither read-only nor decorated by NotMappedAttribute.
• Insertable: Gets the collection of properties that are Selectable, but excluding those in the Generated and Concurrency collections.
• Updatable: Gets the collection of properties that are Insertable, but excluding those in the Keys collection.
• TryGetChanges: Detects changes to updatable properties and fills a dictionary with the names of the changed properties and their values.