Property Handler (Type Level)

This page contains the recommended way of implementing a property handler for specific type.

This property handler is based on database column type (database-bound).

PropertyHandler

Create a class that implements the IPropertyHandler interface.

public class DateTimeKindToUtcPropertyHandler : IPropertyHandler<datetime?, datetime?>
{
    public datetime? Get(datetime? input, ClassProperty property)
    {
        return input.HasValue ? DateTime.SpecifyKind(input.Value, Kind.Utc) : null;
    }

    public datetime? Set(datetime? input, ClassProperty property)
    {
        return input.HasValue ? DateTime.SpecifyKind(input.Value, Kind.Unspecified) : null;
    }
}

public class GuidToStringPropertyHandler : IPropertyHandler<Guid?, string>
{
    public string Get(Guid? input, ClassProperty property)
    {
        return input.HasValue ? input.ToString() : null;
    }

    public Guid? Set(string input, ClassProperty property)
    {
        var output = Guid.Empty;
        if (!string.IsNullOrEmpty(input) && Guid.TryParse(input, out output))
        {
            return output;
        }
        return null;
    }
}

Mapping

Explict

Use the PropertyHandlerMapper class to map the property handlers into the target types.

PropertyHandlerMapper.Add(typeof(DateTime), new DateTimeKindToUtcPropertyHandler());
PropertyHandlerMapper.Add(typeof(Guid), new GuidToStringPropertyHandler());

Implicit

Use the FluentMapper class to map the property handlers into the target types.

FluentMapper
    .Type<DateTime>()
    .PropertyHandler<DateTimeKindToUtcPropertyHandler>();

FluentMapper
    .Type<Guid>()
    .PropertyHandler<GuidToStringPropertyHandler>();

Key Take-aways

Ensure to always make both the TInput and TResult generic types nullable. It is handling both the properties/columns that are nullables/non-nullables.
Make the code snippets to both Get() and Set() method concise and highly performant.
Name the property handler corresponds to its purpose.
Mishandling of the implementation would make your application suffer in performance.