mvvm+DataSet使编程变得简单

来源：互联网发布：宝德网络江西分公司编辑：程序博客网时间：2024/06/05 10:54

mvvm模式下利用DataSet来简化编程，程序短小精悍，实用性强，这里是一个示例，包括2个Model和一个ViewModel,窗口程序的话一般都容易，就不列出了。本示例禁止转载!

public class Student : RaiseBase    {        private StDataSet.studentRow studentrow;        public StDataSet.studentRow Studentrow        {            get { return studentrow; }        }        public int StuID        {            get            {                return xkzdatarow.stuID;            }        }        public string Sname        {            get            {                return studentrow.sname;            }            set            {                if (studentrow.sname != value)                {                    studentrow.sname = value;                    RaisePropertyChanged("Sname");                }            }        }        public int Age        {            get            {                return studentrow.age;            }            set            {                if (studentrow.age != value)                {                    studentrow.age = value;                    RaisePropertyChanged("Age");                }            }        }        public bool IsNew { get; set; }        public int GetMaxStuID()        {            object obj = DataRepository.GetInstance().sda.GetMaxStuID();            if (obj == null)            {                return 1;            }            else            {                return int.Parse(obj.ToString());            }        }        public void SetNewStuID()        {            studentrow.stuID = GetMaxStuID();        }        public static Student GetFromDataRow(StDataSet.studentRow _studentrow)        {            return new Student()            {                studentrow = _studentrow,                IsNew = false,            };        }        public Student(bool isNew)        {studentrow = DataRepository.GetInstance().tbSudents.NewstudentRow();                IsNew = isNew;studentrow.sname = "";//必须初始化，否则报错。studentrow.age = 0;         }        public Student()        {        }    }

public class DataRepository    {        private static DataRepository _instance;        public StDataSet stDataSet;        public StDataSetTableAdapters.studentTableAdapter sda;        public static DataRepository GetInstance()        {            if (_instance == null)            {                _instance = new DataRepository();            }            return _instance;        }        private DataRepository()        {            this.LoadData();        }        public StDataSet.studentDataTable tbStudents        {            get { return stDataSet.student; }        }        public IEnumerable<Student> GetStudents()        {            foreach (StDataSet.studentRow dataRow in tbStudents.Rows)            {                yield return Student.GetFromDataRow(dataRow);            }        }        public void SaveStudent(Student student)        {            if (student.IsNew)            {                AddStudent(student);            }            else            {                sda.Update(student.Studentrow);            }        }        private void AddStudent(Student student)        {            tbStudents.Rows.Add(student.Studentrow);            sda.Update(student.Studentrow);        }        public void DeleteStudent(Student student)        {            sda.Delete(student.Studentrow);        }          private void LoadData()        {            stDataSet = new StDataSet();            sda = new StDataSetTableAdapters.studentTableAdapter();            sda.Fill(stDataSet.student);        }        private void DisposeData()        {            stDataSet.student.Dispose();            stDataSet.Dispose();        }        public void Exit()        {            DisposeData();            _instance = null;        }    }}

public class DisplayStudentViewModel : ViewModelBase    {        private Student _displayedStudent;        public Student DisplayedStudent        {            get { return _displayedStudent; }            set            {                if (_displayedStudent != value)                {                    _displayedStudent = value;                    RaisePropertyChanged("DisplayedStudent");                    RaisePropertyChanged("IsSelected");                }            }        }        public bool IsSelected        {            get { return (DisplayedStudent != null); }        }        private ObservableCollection<Student> students;        public ObservableCollection<Student> Students        {            get            {                if (students == null)                {                    students = new ObservableCollection<Student>();                    foreach (var student in DataRepository.GetInstance().GetStudents())                    {                        students.Add(student);                    }                }                return students;            }          }        enum EditModeType        {            DefaultMode, //非编辑模式            AddNewMode,  //添加            EditMode,    //修改            BgMode,      //变更            ZxMode       //注销        }        EditModeType _editModeType;        private EditModeType editModeType        {            get { return _editModeType; }            set { _editModeType = value; }        }        private RelayCommand _addNewCommand;        private RelayCommand _editCommand;        private RelayCommand _updateCommand;        private RelayCommand _deleteCommand;        private RelayCommand _saveCommand;        private RelayCommand _cancelCommand;        private RelayCommand _exitCommand;        public DisplayStudentViewModel()        {            editModeType = EditModeType.DefaultMode;        }        public ICommand AddCommand        {            get            {                if (this._addNewCommand == null)                {                    this._addNewCommand = new RelayCommand(AddNew,CanAddNew);                }                return this._addNewCommand;            }        }        public ICommand EditCommand        {            get            {                if (this._editCommand == null)                {                    this._editCommand = new RelayCommand(Edit,CanEdit);                }                return this._editCommand;            }        }        public ICommand UpdateCommand        {            get            {                if (this._updateCommand == null)                {                    this._updateCommand = new RelayCommand(Update,CanUpdate);                }                return this._updateCommand;            }        }        public ICommand DeleteCommand        {            get            {                if (this._deleteCommand == null)                {                    this._deleteCommand = new RelayCommand(Delete,CanDelete);                }                return this._deleteCommand;            }        }        public ICommand SaveCommand        {            get            {                if (this._saveCommand == null)                {                    this._saveCommand = new RelayCommand(Save,CanSave);                }                return this._saveCommand;            }        }        public ICommand CancelCommand        {            get            {                if (this._cancelCommand == null)                {                    this._cancelCommand = new RelayCommand(Cancel,CanCancel);                }                return this._cancelCommand;            }        }        public ICommand ExitCommand        {            get            {                if (this._exitCommand == null)                {                    this._exitCommand = new RelayCommand(Exit, CanExit);                }                return this._exitCommand;            }        }        void AddNew(object obj)        {            DisplayedStudent = new Student(true);            editModeType = EditModeType.AddNewMode;        }        bool CanAddNew(object obj)        {            return (IsDefaultMode());        }        void Edit(object obj)        {            editModeType = EditModeType.EditMode;        }        bool CanEdit(object obj)        {            return (IsDefaultMode()) && IsSelected;         }        void Update(object obj)        {            editModeType = EditModeType.BgMode;        }        bool CanUpdate(object obj)        {            return (IsDefaultMode()) && IsSelected;        }        void Cancel(object obj)        {            CancelEdit();//略    editModeType = EditModeType.DefaultMode;        }        bool CanCancel(object obj)        {            return !IsDefaultMode();         }        void Save(object obj)        {            if (!SaveStudent())            {                 return;            }            editModeType = EditModeType.DefaultMode;        }        bool SaveStudent()        {            if (editModeType == EditModeType.AddNewMode)            {                try                {                    DataRepository.GetInstance().SaveStudent(DisplayedStudent);                    DisplayedStudent.IsNew = false;                    DisplayedStudent.SetNewStuID();                    Students.Add(DisplayedStudent);                    return true;                }                catch { return false; }            }            else if (editModeType == EditModeType.EditMode)            {                try                {                    DataRepository.GetInstance().SaveStudent(DisplayedStudent);                    return true;                }                catch { return false; }            }            else if (editModeType == EditModeType.BgMode)            {                try                {                    DataRepository.GetInstance().SaveStudent(DisplayedStudent);//变更数据保存程序略                    return true;                }                catch { return false; }            }            else                try                {                    DataRepository.GetInstance().DeleteStudent(DisplayedStudent);                    Students.Remove(DisplayedStudent);                    return true;                }                catch { return false; }        }        bool CanSave(object obj)        {            return !IsDefaultMode();         }        void Delete(object obj)        {            editModeType = EditModeType.ZxMode;        }        bool CanDelete(object obj) { return (IsDefaultMode()) && IsSelected;  }        void Exit(object obj)        {            DataRepository.GetInstance().Exit();            App.Current.Shutdown();        }        bool CanExit(object obj) { return (IsDefaultMode()); }         private bool IsDefaultMode()        {            return editModeType == EditModeType.DefaultMode;        }    }

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