Question

我的代码： XAML：

<Window x:Class="BindingTut.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <StackPanel>
            <TextBox Text="{Binding FirstName}"/>
            <Button Content="Button" Height="23" Name="button1" Width="75" Click="button1_Click" />
        </StackPanel>
    </Grid>
</Window>

客户类：

public class Customer
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

代码背后：

public partial class MainWindow : Window, INotifyPropertyChanged
{
    private int index = 0;
    public Customer Tmp;
    List<Customer> ar = new List<Customer>();

    public MainWindow()
    {
        InitializeComponent();
        ar.Add(new Customer { FirstName = "qwe", LastName = "rty" });
        ar.Add(new Customer { FirstName = "asd", LastName = "asd" });
        this.Tmp = ar[index];
        this.DataContext = this.Tmp;
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        this.Tmp = ar[++index];
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs("Tmp"));
        }

    }

    public event PropertyChangedEventHandler PropertyChanged;

}

因此，当应用程序加载时，一切都很好 - 文本框显示“qwe”，但是应该加载第二个客户对象的按钮不起作用。我做错了什么？

Answer 1

您没有更改DataContext。您正在更改将DataContext设置为。

的属性中的值

您根本不需要Tmp属性。只需更改事件处理程序中的DataContext，例如：

DataContext = ar[++index];

Answer 2

你需要让Tmp成为一个属性，然后将DataContext绑定到它，就像这样;

private Customer tmp;    
public Customer Tmp {
    get {
        return this.tmp;
    }
    set {
        this.tmp = value;
        if (this.PropertyChanged != null)
            this.PropertyChanged(this, new PropertyChangedEventArgs("Tmp"));
    }
}

public MainWindow()
{
    InitializeComponent();
    ar.Add(new Customer { FirstName = "qwe", LastName = "rty" });
    ar.Add(new Customer { FirstName = "asd", LastName = "asd" });
    this.Tmp = ar[index];
    this.SetBinding(DataContextProperty, new Binding("Tmp") { Source = this });
}

DataBinding，如果DataContext更改则刷新数据

2 个答案: