我正在享受N + 1DaysOfMVVMCross，但我被困在第5天（第2天和第5天的组合）......
我使用第2天开发网格视图UI，并希望使用第5天信息添加一个命令，该命令将在从网格中选择项目时打开辅助视图。 ViewModel中的命令代码从不执行（尽管它确实从按钮执行）。
我认为这个问题与WPF / XAML有关，但我认为我会参考MVVMCross，因为这是我遇到障碍的地方。
感谢您提供任何帮助/提示/指示
一些源代码怎么样......
从视图模型中，抱歉列表初始化我正在慢慢解决这个问题。
using Cirrious.MvvmCross.ViewModels;
using System.Collections.Generic;
using TeleBacteriology.Core.Services;
namespace TeleBacteriology.Core.ViewModels
{
public class WorklistViewModel : MvxViewModel
{
public WorklistViewModel(IWorklistItemService service)
{
var newList = new List<WorklistItem>();
WorklistItem newWorklistItem = service.CreateNewWorklistItem("201401250001", "http://placekitten.com/301/301");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250002", "http://placekitten.com/302/302");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250003", "http://placekitten.com/303/303");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250004", "http://placekitten.com/304/304");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250005", "http://placekitten.com/305/305");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250006", "http://placekitten.com/306/306");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250007", "http://placekitten.com/307/307");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250008", "http://placekitten.com/308/308");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250009", "http://placekitten.com/309/309");
newList.Add(newWorklistItem);
newWorklistItem = service.CreateNewWorklistItem("201401250010", "http://placekitten.com/310/310");
newList.Add(newWorklistItem);
Worklist = newList;
}
private List<WorklistItem> _worklist;
public List<WorklistItem> Worklist
{
get { return _worklist; }
set { _worklist = value; RaisePropertyChanged(() => Worklist); }
}
private MvxCommand _detailsCommand;
public System.Windows.Input.ICommand DetailsCommand
{
get
{
_detailsCommand = _detailsCommand ?? new MvxCommand(DoDetailsCommand);
return _detailsCommand;
}
}
private void DoDetailsCommand()
{
ShowViewModel<PlateDetailsViewModel>();
}
}
}
视图的XAML：
<common:LayoutAwarePage
x:Name="pageRoot"
x:Class="TeleBacteriology.Store.Views.WorklistView"
DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:TeleBacteriology.Store.Views"
xmlns:common="using:TeleBacteriology.Store.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<!-- Collection of items displayed by this page -->
<CollectionViewSource
x:Name="itemsViewSource"
Source="{Binding Worklist}"/>
<DataTemplate x:Key="Worklist250x250ItemTemplate">
<Grid HorizontalAlignment="Left" Width="250" Height="250">
<Border Background="{StaticResource ListViewItemPlaceholderBackgroundThemeBrush}">
<Image Source="{Binding ImageUrl}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}"/>
</Border>
<StackPanel VerticalAlignment="Bottom" Background="{StaticResource ListViewItemOverlayBackgroundThemeBrush}">
<TextBlock Text="{Binding AccessionNum}" Foreground="{StaticResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextStyle}" Height="60" Margin="15,0,15,0"/>
<TextBlock Text="{Binding ImageUrl}" Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/>
</StackPanel>
</Grid>
</DataTemplate>
<DataTemplate x:Key="Worklist80ItemTemplate">
<Grid Margin="6">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Background="{StaticResource ListViewItemPlaceholderBackgroundThemeBrush}" Width="60" Height="60">
<Image Source="{Binding ImageUrl}" Stretch="UniformToFill"/>
</Border>
<StackPanel Grid.Column="1" Margin="10,0,0,0">
<TextBlock Text="{Binding AccessionNum}" Style="{StaticResource ItemTextStyle}" MaxHeight="40"/>
<TextBlock Text="{Binding ImageUrl}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap"/>
</StackPanel>
</Grid>
</DataTemplate>
<!-- TODO: Delete this line if the key AppName is declared in App.xaml -->
<x:String x:Key="AppName">My Application</x:String>
</Page.Resources>
<!--
This grid acts as a root panel for the page that defines two rows:
* Row 0 contains the back button and page title
* Row 1 contains the rest of the page layout
-->
<Grid Style="{StaticResource LayoutRootStyle}">
<Grid.RowDefinitions>
<RowDefinition Height="140"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!-- Horizontal scrolling grid used in most view states -->
<GridView
x:Name="itemGridView"
AutomationProperties.AutomationId="ItemsGridView"
AutomationProperties.Name="Items"
TabIndex="1"
Grid.RowSpan="2"
Padding="116,136,116,46"
ItemsSource="{Binding Source={StaticResource itemsViewSource}}"
ItemTemplate="{StaticResource Worklist250x250ItemTemplate}"
SelectionMode="None"
IsSwipeEnabled="false"
SelectedItem="{Binding DetailsCommand}"/>
<!-- Vertical scrolling list only used when snapped -->
<ListView
x:Name="itemListView"
AutomationProperties.AutomationId="ItemsListView"
AutomationProperties.Name="Items"
TabIndex="1"
Grid.Row="1"
Visibility="Collapsed"
Margin="0,-10,0,0"
Padding="10,0,0,60"
ItemsSource="{Binding Source={StaticResource itemsViewSource}}"
SelectedItem="{Binding DetailsCommand}"
ItemTemplate="{StaticResource Worklist80ItemTemplate}"
SelectionMode="None"
IsSwipeEnabled="false"/>
<!-- Back button and page title -->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button x:Name="backButton" Click="GoBack" IsEnabled="{Binding Frame.CanGoBack, ElementName=pageRoot}" Style="{StaticResource BackButtonStyle}"/>
<TextBlock x:Name="pageTitle" Grid.Column="1" Text="{StaticResource AppName}" IsHitTestVisible="false" Style="{StaticResource PageHeaderTextStyle}"/>
</Grid>
<Grid Grid.Row="2">
<Button Content="Go Details" Command="{Binding DetailsCommand}" />
</Grid>
<VisualStateManager.VisualStateGroups>
<!-- Visual states reflect the application's view state -->
<VisualStateGroup x:Name="ApplicationViewStates">
<VisualState x:Name="FullScreenLandscape"/>
<VisualState x:Name="Filled"/>
<!-- The entire page respects the narrower 100-pixel margin convention for portrait -->
<VisualState x:Name="FullScreenPortrait">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
<DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PortraitBackButtonStyle}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="itemGridView" Storyboard.TargetProperty="Padding">
<DiscreteObjectKeyFrame KeyTime="0" Value="96,136,86,56"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<!--
The back button and title have different styles when snapped, and the list representation is substituted
for the grid displayed in all other view states
-->
<VisualState x:Name="Snapped">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
<DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedBackButtonStyle}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="pageTitle" Storyboard.TargetProperty="Style">
<DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedPageHeaderTextStyle}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="itemListView" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="itemGridView" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
</Grid>
</common:LayoutAwarePage>
我可以发布第二个视图，但我不认为这是必要的。同样，如果我在视图中放置一个按钮并将Command绑定设置为DetailsCommand，则第二个视图弹出就好了。无法使其与网格上的项目选择一起使用。
答案 0 :(得分：1)
从查看代码开始，您似乎误解了ListView的SelectedItem属性。当选择更改时，将使用您的一个WorkListItem对象填充它。
ListView没有像Button那样的命令属性，因此您需要处理ListView的SelectionChanged事件并手动调用Viewmodel上的Command。
您可以在代码隐藏中执行此操作，或者查看其中一个EventToCommand帮助程序，直接在xaml中执行此操作。