Question

我的应用程序中有两个Usercontrol，一个是Mainwindow，另一个是LoginWindow。 Mainwindow.xaml中的标签绑定到＆＃34; UserName＆＃34;应该从LoginWindow更新。

MainWindow.Xaml

<Grid>
        <StackPanel>
        <StackPanel Orientation="Horizontal">
            <Label Content="UserName: " FontWeight="Bold"/>
            <Label Content="{Binding UserName}"/>
        </StackPanel>

            <Button Width="200" Height="30" VerticalAlignment="Bottom" Content="Open Login Window" Click="Button_Click" />

        </StackPanel>
    </Grid>

Mainwindow.xaml.cs 显示在登录窗口

private void Button_Click(object sender, RoutedEventArgs e)
        {
            LoginWindow loginwin = new LoginWindow();
            var host = new Window();
            host.Content = loginwin;
            host.Show();
        }

成功登录后，UserName将显示在Mainwindow上。

在LoginWindow中，我只是放了一个按钮，触发UserName更新到Mainwindow。

LoginWindow.xaml.cs

private LoginClass UserObj { get; set; }

        private void Login_click(object sender, RoutedEventArgs e)
        {
            UserObj = new LoginClass { Username = "From LoginWindow" };
            // How can i update the control <label content > in another userrcontrol 
        }

实现INotifyPropertyChnaged事件的LoginClass.cs

 private string _username;

        public string Username
        {
            get { return _username; }
            set
            {
                _username = value;
                onPropertyChnaged("Username");
            }
        }

        private void onPropertyChnaged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

    }

如果我从Mainwindow提出用户名，并将Datacontext提供给LoginClass的对象，则程序正在按预期工作。

当我从Mainwindow itslef更改属性时，MainWindow上的UI正在更新。

    private LoginClass UserObj { get; set; }    
    private void Button_click(object sender, RoutedEventArgs e)
                {
                    UserObj = new LoginClass { Username = "From MainWindow" };
this.DataContext = UserObj;
                    // INotifyPropertyChanged implementation is working fine as i am giving datacontext to UserObj to get updated 
                }

如何使用Inotifypropertychnaged事件从另一个窗口更新UI。

我在过去4个小时内尝试这个..请求帮助。

非常感谢！

Answer 1

两个窗口应使用相同的DataContext，即您只应创建LoginClass的单个实例：

<强>主窗口：

public partial class MainWindow : Window, INotifyPropertyChanged
{
    LoginClass UserObj = new LoginClass { Username = "From MainWindow" };

    public MainWindow()
    {
        InitializeComponent();
        DataContext = UserObj;
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        LoginWindow loginwin = new LoginWindow();
        loginWin.DataContext = UserObj;
        var host = new Window();
        host.Content = loginwin;
        host.Show();
    }
}

<强>登录窗口：

private void Login_click(object sender, RoutedEventArgs e)
{
    var viewModel = DataContext as LoginClass;
    viewModel.Username = "From LoginWindow"
}

如何使用wpf中的inotifypropertychanged事件从另一个窗口更新属性

1 个答案: