Question

我希望我的自定义网格（对象）能够在viewmodel中“执行”某些内容。 - 通过谷歌搜索分割它的正确方法是使用带有Grid.InputBindings字段的命令。

但是，我似乎完全不知道如何让它发挥作用。我的代码如下：

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace testit
{

    public class ViewModel
    {

        public static readonly RoutedCommand ClickCommand =
            new RoutedUICommand("ClickCommand", "ClickCommand", typeof(ViewModel));
        void SelectElementCanExecute(object sender, CanExecuteRoutedEventArgs e) {
            // The Window gets to determine if the Foo 
            // command can execute at this time.
            e.CanExecute = true;
        }
        void SelectElementExecute(object sender, ExecutedRoutedEventArgs e) {
            // The Window executes the command logic when the user wants to Foo.
            MessageBox.Show("The Window is Fooing...");
        }
    }

    public class CustomGrid : Grid
    {
        private TextBlock tb;
        public CustomGrid(ViewModel model) {
            tb = new TextBlock();
            tb.Text = "hello world";
            Children.Add(tb); // just to show something
            Background = new SolidColorBrush(Colors.LightGray);


            DataContext = model;
            var binding = new MouseBinding(ViewModel.ClickCommand,
                new MouseGesture(MouseAction.LeftClick));
            InputBindings.Add(
                binding
            );
        }
    }

    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private ViewModel vm;
        public MainWindow() {
            InitializeComponent();
            var t = Content as Grid;
            vm = new ViewModel();
            t.Children.Add(new CustomGrid(vm));
        }
    }
}

我希望网格视图显示网格 - 当我点击它时会显示一个消息框。 - 或者至少调试器应该停在我放在那里的断点上。

但似乎没有发生任何事情：好像网格没有正确调用ClickCommand。 - 显然我没有正确注册一切。这样做的正确方法是什么？

为了完整性，这里是xaml（虽然我不希望在xaml文件中设置绑定，但我希望以编程方式执行此操作）：

<Window x:Class="testit.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
            xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
            xmlns:local="clr-namespace:testit"
            mc:Ignorable="d"
            Title="MainWindow" Height="350" Width="525">
    <Grid>
    </Grid>
</Window>

Answer 1

您错过了CommandBinding：

public class CustomGrid : Grid
{
    private TextBlock tb;
    public CustomGrid(ViewModel model)
    {
        tb = new TextBlock();
        tb.Text = "hello world";
        Children.Add(tb); // just to show something
        Background = new SolidColorBrush(Colors.LightGray);


        DataContext = model;
        var binding = new MouseBinding(ViewModel.ClickCommand, new MouseGesture(MouseAction.LeftClick));
        InputBindings.Add(binding);
        var commandBinding = new CommandBinding(ViewModel.ClickCommand, SelectElementExecute);
        CommandBindings.Add(commandBinding);
    }

    void SelectElementExecute(object sender, ExecutedRoutedEventArgs e)
    {
        // The Window executes the command logic when the user wants to Foo.
        MessageBox.Show("The Window is Fooing...");
    }
}

使网格具有左键单击命令，用于动态（以编程方式）生成的网格

1 个答案: