I am getting this error:
'CTest.AA()' is inaccessible due to its protection level.
when compiling this code:
public class A
{
private A()
{
}
}
public class B : A
{
public void SayHello()
{
Console.WriteLine("Hello");
}
}
Can anyone explain why?
Because the default constructor for A is private, try protected A() {}
as the constructor.
Class B
automatically calls the default constructor of A
, if that is inaccessible to B
or there is no default constructor (if you have constructor protected A(string s) {}
) B
can not be instantiated correctly.
The compiler automatically generates the following default constructor in B
public B() : base()
{
}
Where base()
is the actual call to the default constructor of A
.
The constructor on class B
(which is added by the compiler) needs to call the default (no-args) constructor on A
, however the default constructor is marked as private
, which means it can only be called inside A
, hence the error.
Change the constructor on A
to protected
or public
, or internal
if B
is in the same assembly.
The constructor for A is private, it cannot be accessed from outside. If you want to create an instance of A from outside, make the constructor public or protected.
将private A()
更改为public A()
,你很高兴。
It's because A's constructor is private, but B's constructor is public. When you construct B (which constructs A as well) there is no way to access A's private constructor.
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