当按下获取数据按钮时，UserControllers 中的 User_List 发生更改，但主窗口中的列表视图未更新。我使用数据库作为 EntityFramework6.0 我分享给你 UserController.cs(Viewmodel),Users.cs,MainWindow.cs,MainWindow.xaml 我该如何解决这个问题？
MainWindows.cs
public partial class MainWindow : Window ,INotifyPropertyChanged
{
ViewModels.UsersController controller1;
public ObservableCollection<Users> user_List;
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
public ObservableCollection<Users> User_List
{
get { return user_List; }
set {lst1.ItemsSource=user_List = value;OnPropertyChanged("User_List"); }
}
public MainWindow()
{
InitializeComponent();
controller1 = new ViewModels.UsersController();
this.DataContext = controller1;
}
private void Fetch_Data_Button_Click(object sender, RoutedEventArgs e)
{
ViewModels.UsersController controller = new ViewModels.UsersController();
controller.Increase();
lst1.UpdateLayout();
}
}
主窗口.xaml
Window x:Class="MSSQLServer.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MSSQLServer"
xmlns:vw="clr-namespace:MSSQLServer.ViewModels"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800" >
<Window.DataContext>
<vw:UsersController/>
</Window.DataContext>
<Grid>
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
<Button x:Name="Fetch_Data_Button" Click="Fetch_Data_Button_Click" Content="Fetch Data" Width="150" Height="40" FontSize="18" Margin="10,10"></Button>
</StackPanel>
<ListView x:Name="lst1" HorizontalAlignment="Center" VerticalAlignment="Center" Height="300" Width="600" ItemsSource="{Binding User_List,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
<ListView.View>
<GridView>
<GridView.Columns>
<GridViewColumn Header="Id" DisplayMemberBinding="{Binding id,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Width="50"></GridViewColumn>
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding name,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Width="120"></GridViewColumn>
<GridViewColumn Header="Surname" DisplayMemberBinding="{Binding surname,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Width="120"></GridViewColumn>
<GridViewColumn Header="Age" DisplayMemberBinding="{Binding age,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Width="120"></GridViewColumn>
<GridViewColumn Header="E-Mail" DisplayMemberBinding="{Binding email,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Width="120"></GridViewColumn>
</GridView.Columns>
</GridView>
</ListView.View>
</ListView>
</StackPanel>
</Grid>
</Window>
用户控制器.cs
public class UsersController :INotifyPropertyChanged
{
public ObservableCollection<Users> user_List;
public ObservableCollection<Users> User_List
{
get { return user_List; }
set { user_List = value;OnPropertyChanged("User_List"); }
}
public UsersController()
{
Increase();
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
public void Increase()
{
Database1Entities entities = new Database1Entities();
User_List = new ObservableCollection<Users>(entities.Users.ToList());
}
}
和Users.cs
public class Userss : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private int idd;
public int id
{
get { return idd; }
set { idd = value; OnPropertyChanged("id"); }
}
private string namee;
public string name
{
get { return namee; }
set { namee = value; OnPropertyChanged("name"); }
}
private string surnamee;
public string surname
{
get { return surnamee; }
set { surnamee = value; OnPropertyChanged("surname"); }
}
private int agee;
public int age
{
get { return agee; }
set { agee = value; OnPropertyChanged("age"); }
}
private string emaill;
public string email
{
get { return emaill; }
set { emaill = value; OnPropertyChanged("email"); }
}
}
看看我的最新答案：C# wpf listview Binding Problem with observable collection
这是至少在开始时如何使用列表视图/树视图/网格视图的基本示例。如果你尝试它，那么你会将大部分代码移至 ViewModel 部分，但随后你将搜索命令和它们之间的交互（棱镜可能没问题 - 我的意思是事件聚合，不要依赖注入太快）。
您的一个类名为 UsersController。当您切换到 WPF 时，请记住 MVC 模式已不再存在，并且大部分位于 ViewModel 中的某个位置，因此它更像 UserViewModel 或 UsersViewModel。如果我没理解错的话，那么我告诉你，从经典的 MVC（各种实现）切换到某种正确的、令人愉快的 MVVM 是很困难的。
我提供的URL缺少一件主要的事情，那就是标准的ViewModelWrapper，通常称为ViewModelBase或BaseViewModel，你自己称呼它。
它已经成型（不过它应该是我第一篇文章的一部分）：
namespace MyNamespace.ViewModel
{
public class BaseViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler? PropertyChanged;
protected void OnPropertyChanged([CallerMemberName] string propertyName=null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
protected virtual bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = "")
{
if (EqualityComparer<T>.Default.Equals(storage, value))
return false;
storage = value;
this.OnPropertyChanged(propertyName);
return true;
}
}
}
首先，您应该删除以下 XAML，因为您是以编程方式设置
DataContext<Window.DataContext>
<vw:UsersController/>
</Window.DataContext>
其次，您应该调用
Increase()UsersControllerprivate void Fetch_Data_Button_Click(object sender, RoutedEventArgs e)
{
controller1.Increase();
}
这是在 BaseViewModel 中执行此操作的另一种方法：
public event PropertyChangedEventHandler PropertyChanged;
protected bool SetProperty<T>(ref T fieldReference, T newValue, Expression<Func<T>> property)
{
bool valueIsDifferent = false;
if (!object.Equals(fieldReference, newValue))
{
valueIsDifferent = true;
fieldReference = newValue;
var memberExpression = property.Body as MemberExpression;
OnPropertyChanged(memberExpression.Member.Name);
}
return valueIsDifferent;
}
protected void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
这是如何在视图模型中使用它
private int _myProperty;
public int MyProperty
{
get
{
return _myProperty;
}
set
{
SetProperty(ref _myProperty, value, () => MyProperty);
}
}