Map column names with class properties in Dapper-dot-net using ITypeMap and CustomAttributes

Newer-ColumnAttributeTypeMapper.cs

namespace YourNamespace
{
    /// <summary>
    /// Uses the Name value of the ColumnAttribute specified, otherwise maps as usual.
    /// </summary>
    /// <typeparam name="T">The type of the object that this mapper applies to.</typeparam>
    public class ColumnAttributeTypeMapper<T> : FallbackTypeMapper
    {
        public static readonly string ColumnAttributeName = "ColumnAttribute";

        public ColumnAttributeTypeMapper()
            : base(new SqlMapper.ITypeMap[]
            {
                new CustomPropertyTypeMap(typeof (T), SelectProperty),
                new DefaultTypeMap(typeof (T))
            })
        {
        }

        private static PropertyInfo SelectProperty(Type type, string columnName)
        {
            return
                type.GetProperties(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance).
                    FirstOrDefault(
                        prop =>
                        prop.GetCustomAttributes(false)
                            // Search properties to find the one ColumnAttribute applied with Name property set as columnName to be Mapped 
                            .Any(attr => attr.GetType().Name == ColumnAttributeName
                                         &&
                                         attr.GetType().GetProperties(BindingFlags.Public |
                                                                      BindingFlags.NonPublic |
                                                                      BindingFlags.Instance)
                                             .Any(
                                                 f =>
                                                 f.Name == "Name" &&
                                                 f.GetValue(attr).ToString().ToLower() == columnName.ToLower()))
                        && // Also ensure the property is not read-only
                        (prop.DeclaringType == type
                             ? prop.GetSetMethod(true)
                             : prop.DeclaringType.GetProperty(prop.Name,
                                                              BindingFlags.Public | BindingFlags.NonPublic |
                                                              BindingFlags.Instance).GetSetMethod(true)) != null
                    );
        }
    }
    
	[AttributeUsage(AttributeTargets.Property, AllowMultiple = true)]
	public class ColumnAttribute : Attribute
	{
		public string Name { get; set; }
		public ColumnAttribute() {}
		public ColumnAttribute(string Name) { this.Name = Name; }
	}
 
	public class FallbackTypeMapper : SqlMapper.ITypeMap
	{
		private readonly IEnumerable<SqlMapper.ITypeMap> _mappers;
 
		public FallbackTypeMapper(IEnumerable<SqlMapper.ITypeMap> mappers)
		{
			_mappers = mappers;
		}
 
 
		public ConstructorInfo FindConstructor(string[] names, Type[] types)
		{
			foreach (var mapper in _mappers)
			{
				try
				{
					ConstructorInfo result = mapper.FindConstructor(names, types);
					if (result != null)
					{
						return result;
					}
				}
				catch (NotImplementedException)
				{
				}
			}
			return null;
		}
 
		public SqlMapper.IMemberMap GetConstructorParameter(ConstructorInfo constructor, string columnName)
		{
			foreach (var mapper in _mappers)
			{
				try
				{
					var result = mapper.GetConstructorParameter(constructor, columnName);
					if (result != null)
					{
						return result;
					}
				}
				catch (NotImplementedException)
				{
				}
			}
			return null;
		}
 
		public SqlMapper.IMemberMap GetMember(string columnName)
		{
			foreach (var mapper in _mappers)
			{
				try
				{
					var result = mapper.GetMember(columnName);
					if (result != null)
					{
						return result;
					}
				}
				catch (NotImplementedException)
				{
				}
			}
			return null;
		}
	}
}