Tài liệu Classes pdf

[ Team LiB ] A.2 Classes C# uses the class statement along with opening and closing braces, { }, to indicate the beginning and end of a class definition. For example: public class DataException : SystemException { // Member definitions } In VB, a class definition is indicated by the Class . End Class construct: Public Class DataException Inherits SystemException ' member definitions End Class In addition, C# classes can be marked as abstract or sealed; these correspond to the VB MustInherit and NonInheritable keywords, as shown in Table A-2 . Table A-2. C# and equivalent VB class modifiers C# keyword VB keyword abstract MustInherit sealed NonInheritable C# uses the colon to indicate either inheritance or interface implementation. Both the base class and the implemented interfaces are part of the class statement. For example: public class DataSet : MarshalByValueComponent, IListSource, ISupportInitialize, ISerializable In VB, the base class and any implemented interfaces are specified on separate lines immediately following the Class statement. A class's base class is indicated by preceding its name with the Inherits keyword; any implemented interfaces are indicated by the Implements keyword. Hence, the previous definition of the DataSet class in C# would appear as follows in VB: Public Class DataSet Inherits MarshalByValueComponent Implements IListSource, ISupportInitalize, ISerializable [ Team LiB ] . [ Team LiB ] A.2 Classes C# uses the class statement along with opening and closing braces, {. Inherits SystemException ' member definitions End Class In addition, C# classes can be marked as abstract or sealed; these correspond to the VB MustInherit