解析开放泛型类型时,Unity容器抛出ResolutionFailedException

时间:2013-06-26 17:20:23

标签: c# exception generics unity-container

我正在使用Unity2.0,并尝试解析开放的泛型类型。这些类定义如下:

public interface IRepository<T>
{
    void Add(T t);
    void Delete(T t);
    void Save();
}

public class SQLRepository<T> : IRepository<T>
{
    #region IRepository<T> Members
    public void Add(T t)
    {
        Console.WriteLine("SQLRepository.Add()");
    }
    public void Delete(T t)
    {
        Console.WriteLine("SQLRepository.Delete()");
    }
    public void Save()
    {
        Console.WriteLine("SQLRepository.Save()");
    }
    #endregion
}

配置文件如:

<unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
  <namespace name="UnityTry"/>
  <assembly name="UnityTry"/>

  <container>
    <register type="IRepository[]" mapTo="SQLRepository[]" name="SQLRepo" />
  </container>
</unity>

解决IRepository的代码:

        IUnityContainer container = new UnityContainer();

        UnityConfigurationSection section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity");
        section.Containers.Default.Configure(container);

        IRepository<string> rep = container.Resolve<IRepository<string>>();
        rep.Add("World");

当我运行代码时,将在第:

行引发ResolutionFailedException
IRepository<string> rep = container.Resolve<IRepository<string>>();

异常消息是:

Exception is: InvalidOperationException - The current type, UnityTry.IRepository`1    [System.String], is an interface and cannot be constructed. Are you missing a type mapping?

任何人对我做错了什么有任何想法?

1 个答案:

答案 0 :(得分:1)

open generic使用名称“SQLRepo”注册了映射,但是在解析时没有提供名称,因此Unity无法找到映射。尝试按名称解析:

IRepository<string> rep = container.Resolve<IRepository<string>>("SQLRepo");