我正在学习WPF,请原谅我的问题很初级!我有一组项目,我想将该组绑定到网格并将总和绑定到文本框。在网上搜索时,我发现了这个类,即使我们对集合对象的属性进行更改,它也会引发事件。
ObservableCollection not noticing when Item in it changes (even with INotifyPropertyChanged)
但我似乎无法使其在我的代码中工作。
以下是我的代码:
SaleItem
public class SaleItem : INotifyPropertyChanged
{
public int Num { get; set; }
public string ItemID { get; set; }
public string Name { get; set; }
private decimal price;
public decimal Price
{
get { return price; }
set
{
this.price = value;
OnPropertyChanged("Total");
}
}
public int quantity;
public int Quantity
{
get { return quantity; }
set
{
this.quantity = value;
OnPropertyChanged("Total");
}
}
public decimal Total
{
get { return decimal.Round(Price * Quantity, 2, MidpointRounding.AwayFromZero);}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
促销
public class Sale : INotifyPropertyChanged
{
private Decimal _total;
public TrulyObservableCollection<SaleItem> Items { get; set; }
public Sale()
{
Items = new TrulyObservableCollection<SaleItem>();
Items.Add(new SaleItem { ItemID = "1", Name = "Product 1", Price = 10, Quantity = 1 });
Items.Add(new SaleItem { ItemID = "2", Name = "Product 2", Price = 10, Quantity = 1 });
Items.Add(new SaleItem { ItemID = "3", Name = "Product 3", Price = 10, Quantity = 1 });
}
public Decimal Total
{
get
{
return Items.Sum(x => x.Total);
}
set
{
_total = value;
OnPropertyChanged("Total");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
主窗口
public partial class MainWindow : Window
{
public Sale Model { get; set; }
public MainWindow()
{
InitializeComponent();
Model = new Sale();
this.DataContext = Model;
}
private void btnQuantity_Click(object sender, RoutedEventArgs e)
{
Model.Items.Add(new SaleItem { ItemID = "2", Name = "Product 2", Price = 10, Quantity = 1 });
}
}
XAML
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local ="clr-namespace:WpfApplication1"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:Sale />
</Window.DataContext>
<Grid>
<StackPanel>
<DataGrid x:Name="grdItems" ItemsSource="{Binding Items}"></DataGrid>
<TextBlock x:Name="txtTotal" Text="{Binding Total}"/>
<Button x:Name="btnQuantity" Content="Update" Click="btnQuantity_Click"/>
</StackPanel>
</Grid>
我正在尝试测试单击按钮时添加项目并在网格中更新该项目的数量。如果我设置断点并查看Total的值,那么它是正确的,但某种方式它没有在UI上更新。我错过了什么?