Bug with IQueryable and yield syntax: System.BadImageFormatException "An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)"

Matthieu MEZIL — Tue, 14 Oct 2008 08:15:00 GMT

I find a bug if you mix IQueryable and yield syntax.

After Diego has changed a little bit my sample to reproduce it, this is the code he sent to the C# team:

class Program
{
    static void Main(string[] args)
    {
        try
        {
            GetCategoryProductsUsingQueryable(() => new MyProduct(), 1).ToList();
            Console.WriteLine("Queryable succeeds");
        }
        catch (Exception e)
        {
            LogException(e);
        }
    }
 
    private static void LogException(Exception e)
    {
        Console.WriteLine(e.GetType());
        Console.WriteLine(e.Message);
    }
 
 
    private static List<Category> Categories =
        new List<Category> { 
            new Category { 
                CategoryID = 1, 
                Products = new List<Product> { 
                    new Product { 
                        ProductID = 1 } } } };
 
 
    static IEnumerable<P> GetCategoryProductsUsingQueryable<P>(Func<P> newP, int categoryId) where P : IProduct
    {
        var categ = Categories.AsQueryable().FirstOrDefault(c => c.CategoryID == categoryId);
        if (categ == null)
            yield break;
        foreach (var p in categ.Products)
            yield return Load(newP(), p);
    }
 
    static P Load<P>(P item, Product p) where P : IProduct
    {
        item.ID = p.ProductID;
        return item;
    }
}
 
public interface IProduct
{
    int ID { get; set; }
}
 
public class MyProduct : IProduct
{
    public int ID { get; set; }
}
 
public class Category
{
    public int CategoryID { get; set; }
    public List<Product> Products { get; set; }
}
public class Product
{
    public int ProductID { get; set; }
}

In this case, the console output is:

System.BadImageFormatException
An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)

Matthieu MEZIL : LINQ To SQL

Bug with IQueryable and yield syntax: System.BadImageFormatException "An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)"