如何修复未找到的事件处理程序？ [英] How do fix a not found event handler?

问题描述

我已经定义了一个使用New_CLicked事件的工具栏（在MainPage.xaml中）项目（请参阅您尝试过的内容）。这个New_Clicked事件在MainPage.xaml.cs中定义。



现在，如果我正在运行解决方案构建我得到错误

I have defined a Toolbar (in MainPage.xaml) Item which uses a "New_CLicked" Event (See What you have tried). This "New_Clicked" Event is defined in MainPage.xaml.cs.

Now, if i'm running the Solution Build i get the error

Position 8:33. EventHandler "New_Clicked" not found in type "TripLog.Views.MainPage

中找不到EventHandlerNew_Clicked也许我错过了什么？完整的解决方案代码可以查看： GitHub - saigkill / TripLog：我掌握Xamarin.Forms的解决方案 [ ^ ]



我尝试过：



MainPage.xaml：

Maybe i missed anything? The full solution code can be viewed on: GitHub - saigkill/TripLog: My Solution for Mastering Xamarin.Forms[^]

What I have tried:

MainPage.xaml:

<?xml version="1.0" encoding="utf-8" ?>

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"

             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"             

             x:Class="TripLog.Views.MainPage"

             Title="TripLog">



    <ContentPage.ToolbarItems>

        <ToolbarItem Text="New" Clicked="New_Clicked" />

    </ContentPage.ToolbarItems>



    <ContentPage.Content>

        <ListView x:Name="trips" ItemTapped="Trips_ItemTapped" ItemsSource="{Binding LogEntries}">

            <ListView.ItemTemplate>

                <DataTemplate>

                    <TextCell Text="{Binding Title}" Detail="{Binding Notes}" />

                </DataTemplate>

            </ListView.ItemTemplate>

        </ListView>

    </ContentPage.Content>



</ContentPage>

MainPage.xaml.cs：

MainPage.xaml.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using TripLog.Models;
using TripLog.ViewModels;

namespace TripLog.Views
{
	public partial class MainPage : ContentPage
	{
		public MainPage()
		{
			InitializeComponent();

            BindingContext = new MainViewModel();

            void New_Clicked(object sender, EventArgs e)
            {
                Navigation.PushAsync(new NewEntryPage());
            }

            async void Trips_ItemTapped(object sender, ItemTappedEventArgs e)
            {
                var trip = (TripLogEntry)e.Item;
                await Navigation.PushAsync(new DetailPage(trip));

                // Clear selection
                trips.SelectedItem = null;
            }
		}
	}
}

推荐答案

将事件处理程序定义移到外面类构造函数。例如：

Move your event handler definition outside the class constructor. For example:

namespace TripLog.Views
{
	public partial class MainPage : ContentPage
	{
		public MainPage()
		{
			InitializeComponent();
            BindingContext = new MainViewModel();
		}

            void New_Clicked(object sender, EventArgs e)
            {
                Navigation.PushAsync(new NewEntryPage());
            }

            async void Trips_ItemTapped(object sender, ItemTappedEventArgs e)
            {
                var trip = (TripLogEntry)e.Item;
                await Navigation.PushAsync(new DetailPage(trip));

                // Clear selection
                trips.SelectedItem = null;
            }
	}
}

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