Compilerfehler CS0553

[daniel99]

How it is possible to convert from a base-class: public class Test : Object { .... } .... Object obj = new Object(); Test test = (Test)obj;:confused:

[pmarfleet]

You can't do this. Object is the base class and Test the subclass. The Object type knows nothing about the Test type, so you can't create a new instance of Object and cast to Test. Creating a new instance of Test and casting to Object is OK because Test derives from Object and therefore inherits its attributes and behaviour.

Paul Marfleet "No, his mind is not for rent To any God or government" Tom Sawyer - Rush

[daniel99]

Object obj = new Object(); Test test = new Test(); test = (Test)obj; Now I have an InvalidCastException System.InvalidCastException wurde nicht behandelt. Message="Das Objekt des Typs System.Object kann nicht in Typ MyApplication.Test umgewandelt werden." Source="MyApplication"

[pmarfleet]

daniel99 wrote:

Object obj = new Object(); Test test = new Test(); test = (Test)obj; Now I have an InvalidCastException

How is this different to the code in your first post? It still won't work, for the reasons I outlined earlier. I suggest you get a book on OOP and start reading.

Paul Marfleet "No, his mind is not for rent To any God or government" Tom Sawyer - Rush