c# - wpf InvokeCommandAction 绑定(bind)

Question

我在绑定(bind)方面遇到了一些问题。我不知道该怎么做。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using GalaSoft.MvvmLight;
using ManyViews.Model;
using System.Collections.ObjectModel;
using System.Windows.Input;
using GalaSoft.MvvmLight.Command;

namespace ManyViews.ViewModel
{
    class ListViewModel : ViewModelBase
    {
        public void show()
        {
            System.Windows.MessageBox.Show("Raise");
        }
        public ListViewModel()
        {
            EventChecked = new RelayCommand(() => show());
        }
        public ICommand EventChecked { get; set; }
        public ObservableCollection<ListStruct> ShowList
        {
            get { return ListM.Items; }
            set { ListM.Items = value; RaisePropertyChanged("ShowList"); }
        }
        ListModel ListM = new ListModel();
    }
}

如果我需要选择另一个上下文，我总是使用静态资源，但在这种情况下，它在 EventTrigger 中没有属性数据上下文。

<UserControl x:Class="ManyViews.View.List"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" 
         xmlns:test="clr-namespace:ManyViews.ViewModel"
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
<UserControl.Resources>
    <test:ListViewModel x:Key="Test"></test:ListViewModel>
</UserControl.Resources>
<Grid>
    <ListView ItemsSource="{Binding ShowList}">
        <ListView.ItemTemplate>
            <DataTemplate>
                <CheckBox Content="{Binding name}">
                    <i:Interaction.Triggers >
                        <i:EventTrigger EventName="Checked">
                            <i:InvokeCommandAction  Command="{Binding DataContext.EventChecked, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type test:ListViewModel}}}"></i:InvokeCommandAction>
                        </i:EventTrigger>
                    </i:Interaction.Triggers>
                </CheckBox>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>
</Grid>

在这种情况下我有错误

"System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='ManyViews.ViewModel.ListViewModel', AncestorLevel='1''. BindingExpression:Path=DataContext.EventChecked; DataItem=null; target element is 'InvokeCommandAction' (HashCode=43550996); target property is 'Command' (type 'ICommand')"

Answer 1

AncestorType={x:Type test:ListViewModel} 是你的问题。

可视化树中没有比当前项目更高的test:ListViewModel。只有不同的控件，没有( View )模型。

将其更改为搜索 ListView:

<i:InvokeCommandAction  
     Command="{Binding DataContext.EventChecked, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListView}}}">
</i:InvokeCommandAction>