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 3、BaseViewModel

属性改变通知类，多个对象都要使用到。

namespace WPF_MVVM_Demo1.ViewModel { public class BaseViewModel: INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public void RaisePropertyChanged(string propertyName) { if (propertyName != null) { PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName)); } } } }

4、ViewModel类

该类真正的结合Model和View层的一个类，内容主要就在这里。

1、定义了数据源和List集合。

 

/// <summary> /// 可以为数据库传过来的数据 /// </summary> List<User> mylist = new List<User>(); /// <summary> /// /// </summary> ObservableCollection<User> _mylist = new ObservableCollection<User>(); /// <summary> /// 绑定Datagrid的数据源 /// </summary> public ObservableCollection<User> ShowList { get { return _mylist; } set { _mylist = value; RaisePropertyChanged("mylist"); } }

2、事件绑定

这里是定义，后面初始化的时候，需要初始化对应的函数（方法）：

/// <summary> /// 添加事件绑定 /// </summary> public BaseCommands AddCommand { get; set; } /// <summary> /// 修改事件绑定 /// </summary> public BaseCommands UpdateCommand { get; set; } /// <summary> /// 删除事件绑定 /// </summary> public BaseCommands DeleteCommand { get; set; }

3、属性绑定

属性之所以这么写是为了选择datagrid的不同行的时候，通知界面数据发生变化。

 

public int _id; public int ID { get { return _id; } set { _id = value; RaisePropertyChanged("ID"); } } public string _name; public string Name { get => _name; set { _name = value; RaisePropertyChanged("Name"); } } public int _age; public int Age { get=>_age; set { _age = value; RaisePropertyChanged("Age"); } } public string _sex; public string Sex { get=> _sex; set { _sex = value; RaisePropertyChanged("Sex"); } } public string _remark; public string Remarks { get=>_remark; set { _remark = value; RaisePropertyChanged("Remarks"); } }

5、构造函数

构造函数除了初始化绑定事件，另一个就是初始化数据，当然数据也可以从数据库获取，绑定到list集合即可。

//构造函数 public UserViewModel() { InitData(); } void InitData() { AddCommand = new BaseCommands(); AddCommand.ExecuteCommand = new Action<object>(addStudent); UpdateCommand = new BaseCommands(); UpdateCommand.ExecuteCommand = new Action<object>(updateStudent);//修改方法 DeleteCommand = new BaseCommands(); DeleteCommand.ExecuteCommand = new Action<object>(deleteStudent);//修改方法 //SelectCommand = new BaseCommands(); //SelectCommand.ExecuteCommand = new Action<object>(SelectionChangedCommand); mylist.Add(new User() { ID = 1, Name = "张三", Age = 20, Sex = "女", Remarks = "无" }); mylist.Add(new User() { ID = 2, Name = "李四", Age = 21, Sex = "女", Remarks = "无" }); mylist.Add(new User() { ID = 3, Name = "王五", Age = 22, Sex = "女", Remarks = "无" }); mylist.Add(new User() { ID = 4, Name = "赵六", Age = 24, Sex = "女", Remarks = "无" }); Binding(); }

6、Binding绑定

这个函数就是过滤数据之后的绑定，后续可以结合分页、带条件查询处理等都可以在这里处理。

private void Binding() { ShowList.Clear(); mylist.ToList().ForEach(p => ShowList.Add(p)); }

7、添加和修改的实现

public void addStudent(Object parameter) { int id = mylist[mylist.Count() - 1].ID; mylist.Add(new User() { ID = id + 1, Name = Name, Age = Age, Sex = Sex, Remarks = Remarks }); Binding(); } public void updateStudent(object parameter) { if (ID == 0) { MessageBox.Show("请选择修改项"); return; } foreach (var item in mylist) { if (item.ID == ID) { item.ID = ID; item.Name = Name; item.Sex = Sex; item.Remarks = Remarks; item.Age = Age; break; } } Binding(); } public void deleteStudent(object parameter) { if (ID == 0) { MessageBox.Show("请选择删除项"); return; } User user1 = mylist.Single(p => p.ID == ID); mylist.Remove(user1); Binding(); }

8、dagarid的选择事件

这个即上面说的为什么定义了两个，这里用到的就是泛型类，不仅可以拿到选择的dagagird的数据，同时将数据显示在界面上。

public ICommand SelectionChangedCommand { get { return new BaseCommands<DataGrid>((datagrid) =>BtnClick(datagrid)); } } public void BtnClick(object obj) { DataGrid datagrid = (DataGrid)obj; if (datagrid.SelectedItems.Count > 0) { var user = (User)datagrid.SelectedItems[0]; ID = user.ID; Name = user.Name; Age = user.Age; Sex = user.Sex; Remarks = user.Remarks; } }

以上是关于ViewModel的介绍。

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