タブページ内のマスター詳細ページXamarin

Question

UPDATE：SushiHangoverにより示唆されるように

私はいくつかの変更を加えて、私は今、何のエラーを受け取るませんが、私のタブ付きのメニューが表示されていません。

xamarinのドキュメントに示されているようにタブ付きページを追加しようとしていますが、次のエラーが発生します。System.NullReferenceException "オブジェクト参照がオブジェクトのインスタンスに設定されていません。各ページに新しいオブジェクトを宣言する必要がありますか？これはxamlを使用するときに自動的に行われますか？ここで

はここ

at Xamarin.Forms.Platform.Android.AppCompat.Platform.LayoutRootPage(Xamarin.Forms.P age page, Int32 width, Int32 height) [0x0005d] in C:\BuildAgent\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\AppCompat\Plat form.cs:279 
    at Xamarin.Forms.Platform.Android.AppCompat.Platform.Xamarin.Forms.Platform.Android.IPlatformLayout.OnLayout (Boolean changed, Int32 l, Int32 t, Int32 r, Int32 b) [0x00003] in C:\BuildAgent\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\AppCompat\Platform.cs:196 
    at Xamarin.Forms.Platform.Android.PlatformRenderer.OnLayout (Boolean changed, Int32 l, Int32 t, Int32 r, Int32 b) [0x0000e] in C:\BuildAgent\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\PlatformRenderer.cs:73 
    at Android.Views.ViewGroup.n_OnLayout_ZIIII (IntPtr jnienv, IntPtr native__this, Boolean changed, Int32 l, Int32 t, Int32 r, Int32 b) [0x00009] in /Users/builder/data/lanes/3415/7db2aac3/source/monodroid/src/Mono.Android/platforms/android-23/src/generated/Android.Views.ViewGroup.cs:3427 
    at (wrapper dynamic-method) System.Object:d59f31f1-b9b6-40ea-9254-a422fe409750 (intptr,intptr,bool,int,int,int,int) 

は私のコード、

using Xamarin.Forms; 
namespace BSi.Mobile.Events.Views 
{ 
    public partial class MainMasterDetailPage : MasterDetailPage 
    { 
     public MainMasterDetailPage() 
     { 
      InitializeComponent(); 
     } 
    } 
} 

<?xml version="1.0" encoding="utf-8" ?> 
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms" 
       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
       xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms" 
       xmlns:local="clr-namespace:BSi.Mobile.Events.Views;assembly=BSi.Mobile.Events" 
       prism:ViewModelLocator.AutowireViewModel="True" 
       x:Class="BSi.Mobile.Events.Views.MainMasterDetailPage"> 
    <MasterDetailPage.Master> 
     <ContentPage Title="Default" Padding="10"> 
      <StackLayout> 
      <Button Text="Home" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\MainPage"/> 
      <Button Text="Event Schedule" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\EventPage"/> 
      <Button Text="Floor Plan" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\FloorPlanPage"/> 
      <Button Text="Sponsor/Media Partners" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\SponsorsPage"/> 
      <Button Text="Where To Eat" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\FoodNearbyPage"/> 
      </StackLayout> 
     </ContentPage> 
    </MasterDetailPage.Master> 
    <MasterDetailPage.Detail> 
     <TabbedPage> 
      <TabbedPage.Children> 
       <local:MainPage Title="Info" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/> 
       <local:EventPage Title="Sessions" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/> 
       <local:SpeakersPage Title="Speakers" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/> 
       <local:ExhibitsPage Title="Exhibits" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/> 
      </TabbedPage.Children> 
     </TabbedPage> 
    </MasterDetailPage.Detail> 
</MasterDetailPage> 

Answer 1

答えはタブ付きページに表示されるページへの相対的であるコマンドパラメータを使用することでした。

<?xml version="1.0" encoding="utf-8"?> 
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms" 
       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
       xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms" 
       prism:ViewModelLocator.AutowireViewModel="True" 
       x:Class="BSi.Mobile.Events.Views.MainMasterDetailPage"> 
<MasterDetailPage.Master> 
    <ContentPage Title="Default"> 
    <StackLayout> 
     <StackLayout BackgroundColor="{StaticResource iconGray}" Padding="15"  HeightRequest="100"> 
     <Image Source="canfitpro_logo2" HeightRequest="60" HorizontalOptions="Start" VerticalOptions="EndAndExpand" /> 
     </StackLayout> 
     <TableView Intent="Form" HasUnevenRows="True"> 
     <TableRoot> 
      <TableSection Title="Vancouver Fitness Expo"> 
      <ViewCell> 
       <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal"> 
       <StackLayout.GestureRecognizers> 
        <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="EventTabbedPage/NavigationPage/MainPage"/> 
       </StackLayout.GestureRecognizers> 
       <Image Source="icon_home_circle" HeightRequest="40"/> 
       <Label Text="Home" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/> 
       </StackLayout> 
      </ViewCell> 
      <ViewCell> 
       <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal"> 
       <StackLayout.GestureRecognizers> 
        <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="EventTabbedPage/NavigationEventPage"/> 
       </StackLayout.GestureRecognizers> 
       <Image Source="icon_sessions_circle" HeightRequest="40"/> 
       <Label Text="Sessions" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/> 
       </StackLayout> 
      </ViewCell> 
      </TableSection> 
      <TableSection Title="Resources"> 
      <ViewCell> 
       <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal"> 
       <StackLayout.GestureRecognizers> 
        <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage/FloorPlanPage"/> 
       </StackLayout.GestureRecognizers> 
       <Image Source="icon_floormap_circle" HeightRequest="40"/> 
       <Label Text="Floor Plan" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/> 
       </StackLayout> 
      </ViewCell> 
      <ViewCell> 
       <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal"> 
       <StackLayout.GestureRecognizers> 
        <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage/SponsorsPage"/> 
       </StackLayout.GestureRecognizers> 
       <Image Source="icon_partners_circle" HeightRequest="40"/> 
       <Label Text="Sponsor/Media Partners" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/> 
       </StackLayout> 
      </ViewCell> 
      <ViewCell> 
       <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal"> 
       <StackLayout.GestureRecognizers> 
        <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage/FoodNearbyPage"/> 
       </StackLayout.GestureRecognizers> 
       <Image Source="icon_restaurant_circle" HeightRequest="40"/> 
       <Label Text="Where To Eat" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/> 
       </StackLayout> 
      </ViewCell> 
      </TableSection> 
     </TableRoot>   
     </TableView>   
    </StackLayout> 
    </ContentPage> 
    </MasterDetailPage.Master> 
</MasterDetailPage> 

Answer 2

であるあなたは、XAMLでこのようTabbedPage子供追加することができ、私のStackTraceです：

<MasterDetailPage.Detail> 
    <TabbedPage> 
     <TabbedPage.Children> 
      <ContentPage Title="Page 1" Icon="ja.png" /> 
      <ContentPage Title="Page 2" Icon="ja.png" /> 
      <ContentPage Title="Page 3" Icon="ja.png" /> 
     </TabbedPage.Children> 
    </TabbedPage> 
</MasterDetailPage.Detail> 

を単に "あなたの代わりにContentPageのローカルのカスタムページ

またはコード経由：

public TabsPage() 
{ 
    this.Children.Add (new ContentPage() { Title = "Page 1", Icon = "ja.png" }); 
    this.Children.Add (new ContentPage() { Title = "Page 2", Icon = "ja.png" }); 
    this.Children.Add (new ContentPage() { Title = "Page 3", Icon = "ja.png" }); 
}