如何在C#中使用参数的构造函数来创建一个泛型类型参数的实例 [英] How to create an instance of a generic type argument using a parameterized constructor in C#
问题描述
我想写这将记录一个消息,并抛出一个指定的类型与同一消息的异常的helper方法。我有以下几点:
I'm trying to write a helper method that would log a message and throw an exception of a specified type with the same message. I have the following:
private void LogAndThrow<TException>(string message, params object[] args) where TException : Exception, new()
{
message = string.Format(message, args);
Logger.Error(message);
throw new TException(message);
}
在添加新()
约束编译器抱怨说,没有它,我无法实例 TException
。现在该错误消息我得到的是创造一个类型参数TException'的实例时无法提供的参数。我试图与参数的构造函数创建实例,然后设置消息
属性,但它是只读的。
Before adding the new()
constraint the compiler complained that without it I can't instantiate TException
. Now the error message I get is "Cannot provide arguments when creating an instance of a type parameter 'TException'". I tried creating the instance with the parameterless constructor and then set the Message
property but it's read-only.
时这个语言的限制,还是有一个解决方案,我不知道?也许我可以使用反射但这是矫枉过正这样一个简单的任务。 (而且很丑陋,但那是个人意见的问题。)
Is this a limitation of the language or is there a solution I don't know about? Maybe I could use reflection but that's overkill for such a simple task. (And pretty ugly, but that's a matter of personal opinion.)
推荐答案
您可以使用的 Activator.CreateInstance()
(它允许你在参数传递),以创建 TException
的一个实例。然后,你可以扔创建 TException
You can use Activator.CreateInstance()
(which allows you to pass in arguments) to create an instance of TException
. Then, you could throw the created TException
.
例如:
private void LogAndThrow<TException>(string message, params object[] args) where TException : Exception, new()
{
message = string.Format(message, args);
Logger.Error(message);
TException exception = (TException)Activator.CreateInstance(typeof(TException), message);
throw exception;
}
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