C# 如何写入参数null异常和无效异常?
我正在尝试为Register CommandHandler编写一个类C# 如何写入参数null异常和无效异常?,c#,unit-testing,testing,exception-handling,nunit,C#,Unit Testing,Testing,Exception Handling,Nunit,我正在尝试为Register CommandHandler编写一个类 public virtual void RegisterCommandHandler<T>(string messageType, Action<T, MetaData> handler) { _handlers.Add(messageType, (command, metadata) => handler((T)command, metadata)); } 请
public virtual void RegisterCommandHandler<T>(string messageType, Action<T, MetaData> handler)
{
_handlers.Add(messageType, (command, metadata) => handler((T)command, metadata));
}
请帮我写验证
谢谢大家! 您应该直接检查处理程序是否为null
if (handler == null)
throw new ArgumentNullException("handler cannot be null", "handler");
现在出现问题的原因是,如果handler为null,则handler.ToString()将引发NullReferenceException
if (handler == null)
throw new ArgumentNullException("handler cannot be null", "handler");