Visual Studio 问题：MSDN XAML 代码不起作用

Question

我问了一个问题，我不能让我的内容出现在我的 DataGrid 中，然后我想我尝试了一个可行的解决方案并从那里开始。但是，当我偶然发现this MSDN article 并将其 XAML 内容复制粘贴到我新创建的窗口中（在我新的空 WPF 应用程序中）时，问题仍然存在：DataGrid 中没有出现任何内容。 这是我的 Window 的 XAML：

<Window x:Class="DataGridTry.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:DataGridTry"
    mc:Ignorable="d"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <Grid.Resources>
        <!--DataTemplate for Published Date column defined in Grid.Resources.  PublishDate is a property on the ItemsSource of type DateTime -->
        <DataTemplate x:Key="DateTemplate" >
            <StackPanel Width="20" Height="30">
                <Border Background="LightBlue" BorderBrush="Black" BorderThickness="1">
                    <TextBlock Text="{Binding PublishDate, StringFormat={}{0:MMM}}" FontSize="8" HorizontalAlignment="Center" />
                </Border>
                <Border Background="White" BorderBrush="Black" BorderThickness="1">
                    <TextBlock Text="{Binding PublishDate, StringFormat={}{0:yyyy}}" FontSize="8" FontWeight="Bold" HorizontalAlignment="Center" />
                </Border>
            </StackPanel>
        </DataTemplate>
        <!--DataTemplate for the Published Date column when in edit mode. -->
        <DataTemplate x:Key="EditingDateTemplate">
            <DatePicker SelectedDate="{Binding PublishDate}"  />
        </DataTemplate>
    </Grid.Resources>
    <DataGrid Name="DG1" ItemsSource="{Binding}" AutoGenerateColumns="False" >
        <DataGrid.Columns>
            <!--Custom column that shows the published date-->
            <DataGridTemplateColumn Header="Publish Date" CellTemplate="{StaticResource DateTemplate}" CellEditingTemplate="{StaticResource EditingDateTemplate}" />
        </DataGrid.Columns>
    </DataGrid>
</Grid>

如您所见，只是复制粘贴，但仍然没有给出预期的结果。我要重新安装VS吗？ （使用 2015 ATM）。什么可能导致问题？

Answer 1

您没有正确绑定 DataGrid。您尚未发布模型，但作为示例，请尝试在新窗口的代码隐藏中创建 ObservableCollection 并将您的 DataGrid 绑定到该集合：

    <Window x:Class="DataGridTry.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:DataGridTry"
    mc:Ignorable="d" Name="Root"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <Grid.Resources>
        <!--DataTemplate for Published Date column defined in Grid.Resources.  PublishDate is a property on the ItemsSource of type DateTime -->
        <DataTemplate x:Key="DateTemplate" >
            <StackPanel Width="20" Height="30">
                <Border Background="LightBlue" BorderBrush="Black" BorderThickness="1">
                    <TextBlock Text="{Binding PublishDate, StringFormat={}{0:MMM}}" FontSize="8" HorizontalAlignment="Center" />
                </Border>
                <Border Background="White" BorderBrush="Black" BorderThickness="1">
                    <TextBlock Text="{Binding PublishDate, StringFormat={}{0:yyyy}}" FontSize="8" FontWeight="Bold" HorizontalAlignment="Center" />
                </Border>
            </StackPanel>
        </DataTemplate>
        <!--DataTemplate for the Published Date column when in edit mode. -->
        <DataTemplate x:Key="EditingDateTemplate">
            <DatePicker SelectedDate="{Binding PublishDate}"  />
        </DataTemplate>
    </Grid.Resources>
    <DataGrid DataContext="{Binding ElementName=Root}" Name="DG1" ItemsSource="{Binding PublishedDateModels}" AutoGenerateColumns="False" >
        <DataGrid.Columns>
            <!--Custom column that shows the published date-->
            <DataGridTemplateColumn Header="Publish Date" CellTemplate="{StaticResource DateTemplate}" CellEditingTemplate="{StaticResource EditingDateTemplate}" />
        </DataGrid.Columns>
    </DataGrid>
</Grid>

示例模型：

public class PublishedDateModel : INotifyPropertyChanged
    {
        private DateTime _publishDate;

        public DateTime PublishDate
        {
            get { return _publishDate; }
            set
            {
                if (value.Equals(_publishDate)) return;
                _publishDate = value;
                OnPropertyChanged();
            }
        }

        public PublishedDateModel(DateTime date)
        {
            PublishDate = date;
        }


        public event PropertyChangedEventHandler PropertyChanged;

        [NotifyPropertyChangedInvocator]
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

在您的 MainWindow.cs 文件中：

public ObservableCollection<PublishedDateModel> PublishedDateModels { get; set; }

        public MainWindow()
        {
            PublishedDateModels = new ObservableCollection<PublishedDateModel>(new[]
            {
                new PublishedDateModel(DateTime.Now), 
                new PublishedDateModel(DateTime.Now.AddDays(1)), 
                new PublishedDateModel(DateTime.Now.AddDays(-1)), 
            });
            InitializeComponent();
        }

Answer 2

XAML 没有任何问题。只是不完整。

 Name="DG1" ItemsSource="{Binding}"

DataGrid DG1 需要绑定数据。

举个简单的例子，将其添加到代码隐藏 (MainWindow.xaml.cs)：

using System.Collections.ObjectModel;

namespace DataGridTry
{
    public class ThingBeingPublished
    {
        public DateTime PublishDate { get; set; }
    };

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            var listOfThings = new ObservableCollection<ThingBeingPublished();

            listOfThings.Add(new ThingBeingPublished() { PublishDate = DateTime.Now.AddDays(-2) });
            listOfThings.Add(new ThingBeingPublished() { PublishDate = DateTime.Now.AddDays(-1) });
            listOfThings.Add(new ThingBeingPublished() { PublishDate = DateTime.Now });

            DG1.ItemsSource = listOfThings;
        }
    }
}

现在你应该看到：

理想情况下，这不会在代码隐藏中完成。