ExecutionEngineException thrown when mapping with IDataReader to DTO with a different datatype for a property

From @janv8000 on November 19, 2012 8:29

An ExecutionEngineException without any useful debug information is thrown when executing the following code. This only happens with a Release build without a debugger attached. When debugging the data comes out just fine.

Versions used: Automapper NuGet version 2.2.0 .NET 4

Database schema:

CREATE TABLE [dbo].[Foo](
[Bar] [numeric](4, 0) NOT NULL,
[Baz] [nvarchar](50) NOT NULL
)

INSERT [dbo].[Foo] ([Bar], [Baz]) VALUES (CAST(0 AS Numeric(4, 0)), N'0')
INSERT [dbo].[Foo] ([Bar], [Baz]) VALUES (CAST(112 AS Numeric(4, 0)), N'112')

Code:

class Program
{
    public class Foo
    {
        public int Bar { get; set; }
        public string Baz { get; set; }
    }

    static void Main(string[] args)
    {
        //Build as release and X86 or Any CPU
        var stringBuilder = new StringBuilder();
        stringBuilder.Append("SELECT Bar , ");// Bar is actually a numeric(4,0) but declared in dto as int
        stringBuilder.Append("       Baz ");
        stringBuilder.Append("FROM   Foo");

        List<Foo> result;
        using (var connection = new SqlConnection("Server=localsqlalias;Database=AutoMapperTest;Integrated Security=True;"))
        {
            connection.Open();
            using (var sqlCommand = new SqlCommand(stringBuilder.ToString(), connection))
            {
                using (var sqlDataReader = sqlCommand.ExecuteReader())
                {
                    Mapper.CreateMap<IDataReader, IEnumerable<Foo>>();
                    result = Mapper.Map<IDataReader, IEnumerable<Foo>>((IDataReader)sqlDataReader).ToList();
                }
            }
        }

        foreach (var aResult in result)
        {
            Console.WriteLine("{0} {1}", aResult.Bar, aResult.Baz);
        }

        Console.WriteLine("Press enter to quit");
        Console.ReadLine();
    }
}

Copied from original issue: AutoMapper/AutoMapper#273

[jumas45]

@jbogard Issue still exists. Is this going to be fixed in version 4.1?

[jumas45]

Temporary Workaround: In my SQL whenever there is a datatype of int, long, decimal,float, double, I am casting it as a string and then I am creating an explicit .ForMember mapping for those columns. It’s painful but works.