public AddStudentViewModel()
        {
            StudentModel = new StudentsModel();
               SutdentsInfoValidation stuVa=new SutdentsInfoValidation ();

               AddStudentCmd = new MyCommands(AddStuMethod);
               ExitCmd = new MyCommands(ExitMethod);
        }
 public SearchStudentsViewModel()
 {
     SSModel = new SearchStudentsModel();
        SearchByGradesCmd = new MyCommands(SearchByGradesMethon);
        DeleteCmd = new MyCommands(DeleteDataMethod);
 }
 public ManagementViewModel()
 {
     ShowAddStuWindowCmd = new MyCommands(ShowAddStuWindowMethod);
        ManageCmd = new MyCommands(ManageMethod);
        ExitSysCmd = new MyCommands(ExitMethod);
 }
 public LogInViewModel()
 {
     LogInModel = new LogInModel() { UserName = "******", Password = "******" };
     LogInCommand = new MyCommands(LoginMethod);
     LogOutCommand = new MyCommands(LogOutMethod);
 }