c# - 系统.InvalidOperationException : The specified cast from a materialized 'System.Int32' type to a nullable 'Country' type is not valid

Question

我有一个特定的单元测试在我的个人电脑上运行良好，但每当我让 TFS 运行测试时，它会失败并出现以下异常 -

System.InvalidOperationException: The specified cast from a materialized 'System.Int32' type to a nullable 'Country' type is not valid.

通过跟踪堆栈，下面的方法有问题——

public IEnumerable<IAddress> AddressSelectAll(long userID)
{
    using (var context = new Entities())
    {
        var addresses = context.Customers
                               .Where(x => x.UserId == userID)
                               .Select(y => new Address
                                                {
                                                    Address1 = y.Address1,
                                                    Address2 = y.Address2,
                                                    Address3 = y.Address3,
                                                    AddressID = y.AddressId,
                                                    City = y.City,
                                                    Country = y.Country != null ? (Country)y.Country : (Country?)null,
                                                    Postcode = y.Postcode,
                                                    State = y.State,
                                                    RecordEntryDate = y.RecordEntryDate,
                                                    Type = (AddressType)EFFunctions.ConvertToInt32(y.AddressType),
                                                    UserID = y.UserId
                                                }).ToList();

        return addresses.ToList();
    }
}

万一它是相关的(怀疑它是)，我的 EFFunctions 类被定义为 -

public static class EFFunctions
{
    [EdmFunction("Model", "ConvertToInt32")]
    public static int ConvertToInt32(string text)
    {
        var result = string.IsNullOrEmpty(text) ? 0 : Convert.ToInt32(text);

        return result;
    }
}

我的 .edmx 中包含以下内容 -

<Function Name="ConvertToInt32" ReturnType="Edm.Int32">
  <Parameter Name="v" Type="Edm.String" />
  <DefiningExpression>
    CAST(v AS Edm.Int32)
  </DefiningExpression>
</Function>

谁能告诉我我做错了什么？

Answer 1

您的问题可能出在线路(或部分线路)上

Country = y.Country != null ? (Country)y.Country : (Country?)null

在一种情况下，您将值转换到 Country 和 Country？在另一个。也许您可以将值替换为 -1，或者更可靠地，将 Customer.Country 类型更改为 Country？而不是国家/地区。