NavigationService.navigate 空引用异常

本文介绍了NavigationService.navigate 空引用异常的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在学习 WP 编码，但遇到了无法解决的问题:/

I'm learning WP coding and I have problem that I can't solve :/

try
 {
    NavigationService.Navigate(new Uri("/edit.xaml", UriKind.Relative));
 }
 catch (Exception ex)
 {
     MessageBox.Show(ex.Message.ToString(),"Error!",MessageBoxButton.OK);
 }

edit.xaml 与 MainPage.xaml 位于同一目录

edit.xaml is in the same directory as MainPage.xaml

它抛出NullReferenceException"

It throws "NullReferenceException"

推荐答案

因为你得到一个 NullReferenceException，我猜你正在尝试调用 NavigationService.Navigate早期，例如在 MainPage 构造函数中.

Because you get an NullReferenceException, my guess is that you are trying to call NavigationService.Navigate to early, for example in the MainPage constructor.

相反，如果您想在加载页面时立即导航，请尝试通过将以下代码添加到 MainPage 类来覆盖 OnNavigatedTo 事件来实现:

Instead, if you want to navigate immedietly when page is loaded for example, try doing it by overriding the OnNavigatedTo event by adding this code to the MainPage class:

protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
   NavigationService.Navigate(new Uri("/Page1.xaml", UriKind.Relative));
}

这篇关于NavigationService.navigate 空引用异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！