c# 4.0 - 我的实体框架预编译的 LINQ 类引发 System.TypeInitializationExcept

Question

>我有一个用于LINQ扩展方法的类。我从以下班级获得System.TypeInitializationException：

public static class CarLib {
    private readonly static IOPTS_EFEntities Context = new myEFEntities();
    public IQueryable<Transmission> GetTransmissions(this Car car, IEFEntities context = null) {
        if (context == null) 
        context = Context;
        return SelectCarWithTransmissionCompiled(car, context);
    }
    public IQueryable<Tire> GetTires(this Car car, IEFEntities context=null) {
         if (context == null) 
         context = Context;
         return SelectTiresCompiled(car, context);
    }
    private static readonly Func<Car, IEFEntities, IQueryable<Transmission>> SelectTransmissionsCompiled = SelectTransmissions.Compile();
    private static readonly Func<Car, IEFEntities, IQueryable<Tire>> SelectTiresCompiled = SelectTires.Compile();
    private static readonly Expression<Func<Car, IEFEntities, IQueryable<Transmission>>> SelectTransmissions= (myCar,context) => 
                    from trans in context.Transmissions
                    where trans.CarId == myCar.Id 
                    select trans;
    private static readonly Expression<Func<Car, IEFEntities, IQueryable<Tire>>> SelectTires = (car,context) =>
                    from tire in context.Tires
                    where car.Id == tire.CarId
                    && accused.Ssn.IsValidSsn()
                    && !tire.Brand.IsNullEmptyOrWhitespace()
                    && !tire.Diameter.IsNullEmptyOrWhitespace()
                    && !tire.Weight.IsNullEmptyOrWhitespace()
                    && tire.Price.IsPopulated()
                    select tire;
    }

Answer 1

在单元测试（或只是一个方法）中尝试静态字段（上下文初始化和查询编译）中的代码，并查看实际异常及其堆栈跟踪。

此外，在静态字段中拥有 DataContext 是一个定时炸弹。在每个方法中创建一个新的方法或共享它，将其存储在受控位置（如HttpContext.Item，Call.Context等）