如何使用PopAsync将数据传递到上一页? [英] How to pass data to the previous page using PopAsync?

问题描述

请考虑以下情形:

1. 用户在第1页上
2. 他单击按钮将其移至第2页(称为await Navigation.PushAsync(new SomePage());)
3. 完成某些操作后，他单击确定"按钮
4. 单击确定"后，应用程序将调用PopAsync移至第1页并向其中发送一些数据(第2页上的活动结果).

1. User is on some Page 1
2. He clicks button that moves him to Page 2 (calling await Navigation.PushAsync(new SomePage()); )
3. After finishing certain action, he clicks "OK" button
4. After clicking "OK", app calls PopAsync to move to Page 1 and sends there some data (result of activity on Page 2).

如何从第1页的第2页接收数据?

How can I receive data from Page 2 in Page 1?

推荐答案

最好的方法(IMO)是通过引发事件来处理原始页面的弹出消息.像这样:

The best way (IMO) would be to handle the pop from the originating page by raising an event. Something like this:

public class LoginPage : ContentPage
{
    public event EventHandler LoginSucceeded;

    public event EventHandler LoginFailed;

    private void OnLoginSucceeded()
    {
        if (LoginSucceeded != null)
        {
            LoginSucceeded(this, EventArgs.Empty);
        }
    }

    private void OnLoginFailed()
    {
        if (LoginFailed != null)
        {
            LoginFailed(this, EventArgs.Empty);
        }
    }
}

和来自app.cs

public class App : Application
{
    public App()
    {
        var loginPage = new LoginPage();
        loginPage.LoginSucceeded += HandleLoginSucceeded;
        MainPage = loginPage;
    }

    private void HandleLoginSucceeded(object sender, EventArgs e)
    {
        MainPage = new MainPage();
    }
}

您可以通过此处了解更多信息–确实不错文章

You can read more about it over here -- Really good article

另一种选择是使用 MessagingCenter

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