构造函数和抛出异常

Question

Is this the best way for me to abort instantiation of an object if it's parameters are not passed in with valid data?

protected Command(string commandKey)
{
    if(commandKey == null) throw new ArgumentNullException("commandKey", "Command Key cannot be null as it is required internally by Command");
    if(commandKey == "") throw new ArgumentException("Command Key cannot be an empty string");
    CommandKey = commandKey;
}

Answer 1

Yes. It is common practice to validate the arguments in constructors and throw an exception if they are invalid.

Answer 2

It's perfectly fine. Constructors do not return anything so how else would you know if something went wrong? You could have a bool to set it to some uninitialized state but I would go with exceptions.

Also :

if(String.IsNullOrEmpty(commandKey)) //throw exectpion

Answer 3

In this case you could use the static method string.IsNullOrEmpty(commandKey):

protected Command(string commandKey) 
{ 
    if(string.IsNullOrEmpty(commandKey))
        throw new ArgumentException("commandKey");
    //something
} 

Answer 4

如果您仔细阅读框架源代码，这正是Microsoft所做的事情，因此我怀疑它是完全有效的。

Answer 5

如果在构造函数中进行验证并在出现问题时引发异常，那将是非常好的。