Apologies first for the image. I don't have the source.

My question is why is it possible to "set" a readonly dictionary (last line of the program) ? What's the difference if the dictionary is NOT declared as readonly ?

Thanks.

CodePudding user response：

The reason is that your dictionary is not read only. It is a "regular" dictionary with all its functionality. What is read only is the field _dictionary which holds a reference to the actual Dictionary. Therefore, you cannot replace the dictionary assigned to _dictionary.

CodePudding user response：

Because "readonly" here is field _dictionary itself. But Dictionary class is mutable and you still can change internal values.