Xamarin Forms-如何在另一个内部显示一个xaml的内容 [英] Xamarin Forms - How to display content from one xaml inside another

问题描述

我已经习惯了Android开发，并且在完成我认为很简单的任务时遇到了一些困难.

I'm used to Android development, and am having some difficulty accomplishing what I would think is a simple task.

我有一个MasterDetailPage(称为ContainerView.xaml).

I have a MasterDetailPage (called ContainerView.xaml).

Master是我的导航栏(称为NavbarView.xaml).

The Master is my navigation bar (called NavbarView.xaml).

详细信息"应该是带有固定标题栏的页面，并且可以根据用户选择交换视图".

The Details is supposed to be a page with a fixed title bar, and a "view" I can can swap per user choices.

详细信息"页面称为MainView.xaml.

The Details page is called MainView.xaml.

我想在顶部显示的标题称为TitleBarView.xaml.

The Title I'd like to display at the top and is called TitleBarView.xaml.

然后我有很多内容页面，例如Page1View.xaml.

Then I have a number of content pages such as Page1View.xaml.

在我的ContainerView.xaml中:

in my ContainerView.xaml:

<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms"             
                  xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"       
                  x:Class="MyApp.ContainerView"
                  IsGestureEnabled="True"
                  MasterBehavior="Popover"
                  Title="MasterDetail Page">
  <MasterDetailPage.Master>
  </MasterDetailPage.Master>
  <MasterDetailPage.Detail>
  </MasterDetailPage.Detail>  
</MasterDetailPage>

在我的NavbarView.xaml中-这是Master

in my NavbarView.xaml - this is the Master

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
             x:Class="MyApp.NavBarView"
             Title="Nav Bar">  
  <ContentPage.Content>  
    <StackLayout Orientation="Vertical">
      <Label Text="{Binding Item1}"/>
      <Button Text="Options" Command="{Binding Option1Command}"/>
    </StackLayout >
  </ContentPage.Content>  
</ContentPage>

在我的MainView.xaml中-这是详细信息

in my MainView.xaml - this is the details

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MyApp.MainView"
             Title="Main View">
  <ContentPage.Content>
  // what to put here to show the TitleBarView.xaml?
  // what to put here to show my content xaml pages?
  </ContentPage.Content>
</ContentPage>

在我的TitleBarView.xaml中

in my TitleBarView.xaml

<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MyApp.TitleBarView">
  <ContentView.Content>    
    <StackLayout Orientation="Horizontal">
      <Label Text="{Binding Item1}"/>
      <Button Text="Options" Command="{Binding OptionsCommand}"/>
    </StackLayout>    
  </ContentView.Content>
</ContentView>

和通用内容视图，当然，我想在其他许多内容之间进行切换

and a generic content view, of course there will be many others I want to switch between

<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MyApp.Page1View">
  <ContentView.Content>
    <StackLayout Orientation="Vertical">
      <Label Text="{Binding Info}"/>
      <Button Text="Log In" Command="{Binding GoToPage2Command}"/>
    </StackLayout >
  </ContentView.Content>
</ContentView>

我正在使用MVVM模型并具有此代码，但似乎不能仅使基础知识正常工作. 母版页显示正常. 如果详细信息"页面只是一个简单的页面，则可以使用，但是我不知道如何插入TitleBar和换出"Content".

I am using the MVVM model and have this code, but can't seem to get just the basics working. The Master page displays fine. If the Details page is just a simple page, it works, but I can't figure out how to insert the TitleBar and swap out the "Content".

ContainerView containerPage = new ContainerView(); 
ContainerViewModel containerVM = new ContainerViewModel();
containerPage.BindingContext = containerVM;

NavBarView navigationBar = new NavBarView();
navigationBar.Title = "Navigation Bar"; // required, otherwise I get an exception.
NavBarViewModel navigationBarVM = new NavBarViewModel();
navigationBar.BindingContext = navigationBarVM;

MainView mainView = new MainView();
mainView.Title = "MainView";
MainViewModel mainViewVM = new MainViewModel();
mainView.BindingContext = mainViewVM;

TitleBarView titleBar = new TitleBarView();
TitleBarViewModel titleBarVM = new TitleBarViewModel();
titleBar.BindingContext = titleBarVM;

Page1View page1 = new Page1View();
Page1ViewModel page1VM = new Page1ViewModel();
page1.BindingContext = page1VM;

mainView.Content = new StackLayout()
{
    Orientation = StackOrientation.Vertical,
    Children = 
    {
        new Label { Text = "I'm Content!" },
        new Label { Text = "I'm Content!" },
        //titleBar.Content,
        //loginView.Content
    }
};

containerPage.MasterBehavior = MasterBehavior.Popover;
containerPage.Master = navigationBar;
containerPage.Detail = new NavigationPage(mainView);

我确定我缺少一个基本概念.任何帮助将不胜感激

I'm sure I'm missing a fundamental concept. Any help would be appreciated

推荐答案

Xaml可以实例化在代码或Xaml中定义的任何控件，因此对于TitleBarView，您可以在任何Xaml中实例化它，方法是

Xaml can instantiate any control, defined in code or in Xaml, so in case of TitleBarView, you can instantiate it in any Xaml by

<xmlnsprefix:TitleBarView />

问题是设置正确的xmlnsprefix.每个xaml文件都定义了几个xmlns，您可以添加自己的xmlns，如下所示:

The problem is to set the right xmlnsprefix. Every xaml file define a few xmlns and you can add your own, like this:

xmlns:local="clr-namespace:MyApp"

这意味着Xml名称空间"local"将引用当前程序集中的clr名称空间"MyApp".

and it'll mean that the Xml namespace 'local' will reference the clr namespace 'MyApp' in the current assembly.

因此MainView变为:

So you MainView becomes:

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
   xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
   xmlns:local="clr-namespace:MyApp"
   x:Class="MyApp.MainView"
   Title="Main View">
  <ContentPage.Content>
   <local:TitleBarView />
  </ContentPage.Content>
</ContentPage>

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