MapDataReader 1.0.3

MapDataReader

Super fast mapping DataReader to a strongly typed object. High performance, lighweight (12Kb dll), uses AOT source generation and no reflection, mapping code is generated at compile time.

Benchmarks

20X faster than using reflection, even with caching. Benchmark for a tiny class with 5 string properties:

Install via Nuget

Install-Package MapDataReader

Usage

using MapDataReader;

[GenerateDataReaderMapper] // <-- mark your class with this attribute
public class MyClass
{
	public int ID { get; set; }
	public string Name { get; set; }
	public int Size { get; set; }
	public bool Enabled { get; set; }
}

//ToMyClass() method code is generated at compile time
List<MyClass> result = dbconnection.ExecuteReader("SELECT * FROM MyTable").ToMyClass();

Some notes

• The ToMyClass() method above - is an extension method generated at compile time. You can even "go to definition" in Visual Studio and examine its code.
• The naming convention is ToCLASSNAME() we can't use generics here, since <T> is not part of method signatures in C# (considered in later versions of C#).
• Maps properies with public setters only.
• The reader is being closed after mapping, so don't reuse it.
• The example above uses .ExecuteReader method from Dapper, but you can generate the reader in any way you want, e.g. the plain SqlCommand.ExecuteReader will also work.
• Supports enum properties based on int and other implicit casting (sometimes a DataReader may decide to return byte for small integer database value, and it maps to int perfectly via some unboxing magic)
• Properly maps DBNull to null.
• Complex-type properties may not work.
• netstandard 2.0
• Contributions are very welcome.