Question

早上好。

我正在尝试从Create a custom DataGrid's ItemsSource复制解决方案，但我的行没有填充。

列显示正确的标题，但网格中没有数据。

我是WPF和XAML的新手，有谁能告诉我我做错了什么？

using System;
using System.Windows;
using System.ComponentModel;
using System.Collections.ObjectModel;
using System.Runtime.CompilerServices;

namespace WPFBindingDataGridTest2
{
    public partial class MainWindow : Window
    {
        public ObservableCollection<MyObject> myList { get; set; }

        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;

            testClass = new ObservableCollection<TestClass>();
            testClass.Add(new TestClass(NameValue: "John"));
            testClass.Add(new TestClass(NameValue: "Frank"));
            testClass.Add(new TestClass(NameValue: "Sarah"));
            testClass.Add(new TestClass(NameValue: "David"));


        }
    }

    class TestClass : INotifyPropertyChanged
    {
        private string name;

        public TestClass(string NameValue)
        {
            this.Name = NameValue;
        }

        public String Name
        {
            get { return name; }
            set { this.name = value; NotifyPropertyChanged(); }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
        {
            if (this.PropertyChanged != null)
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

和XAML ......

<Grid>
    <DataGrid x:Name="dataGrid" ItemsSource="{Binding testClass}" AutoGenerateColumns="False">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Name" Binding="{Binding Name}"/>
        </DataGrid.Columns>
    </DataGrid>
</Grid>

我得到的错误是

System.Windows.Data Error: 40 :  
BindingExpression path error:  
'testClass' property not found on 'object'''MainWindow' 
(Name='')'.BindingExpression:  
Path=testClass;  
DataItem='MainWindow' (Name='');  
target element is 'DataGrid' (Name='dataGrid');  
target property is 'ItemsSource' (type 'IEnumerable')

我觉得我如此接近这一点，但我只是缺少一件事可能数据上下文错了吗？

Answer 1

分配DataContext时，myList为null。在以后创建时，属性不会报告有关更改（通过事件）

的信息

快速解决方法是更改操作顺序：

public MainWindow()
{
    myList = new ObservableCollection<MyObject>
    {
      new MyObject() { MyID = "6222" },
      new MyObject() { MyID = "12" },
      new MyObject() { MyID = "666" }
    };
    this.DataContext = this;
    InitializeComponent();
}

还修复了列绑定（Binding="{Binding MyID}"）或属性名称（MyId），因为绑定路径应该与属性名称匹配

但我建议使用INotifyPropertyChanged属性创建一个单独的类（实现myList），并使用该类的实例（视图模型）来设置窗口的DataContext。

Answer 2

想出来。

var arrayOne = [{"Name":"job","SubscriptionGUID":"8ead7edfa460"},{"Name":"TestJobSQL","SubscriptionGUID":"09e7dbff7779"}];
var arrayTwo = [{"UserSubscriptionID":13,"SubscriptionGUID":"8ead7edfa460","Name":"job"}];
var arrayDiff = [];
arrayOne.forEach(function(item, index){
    var found = false;
    arrayTwo.forEach(function(item1, index1){
        if(item.Name == item1.Name) {
            found = true;
        }   
    })
    if(found == false) {
        arrayDiff.push({ Name : item.Name});
    }
})
console.log(arrayDiff);

XAML

using System;
using System.Windows;
using System.ComponentModel;
using System.Collections.ObjectModel;
using System.Runtime.CompilerServices;

namespace WPFBindingDataGridTest2
{
    public partial class MainWindow : Window
    {
        private ObservableCollection<TestClass> testClass;

        public MainWindow()
        {
            InitializeComponent();

            testClass = new ObservableCollection<TestClass>();
            testClass.Add(new TestClass(NameValue: "John"));
            testClass.Add(new TestClass(NameValue: "Frank"));
            testClass.Add(new TestClass(NameValue: "Sarah"));
            testClass.Add(new TestClass(NameValue: "David"));

            // this.DataContext = this does not appear to be nessecary if it the class is stored in the main window
            dataGrid.ItemsSource = testClass;

        }
    }

    class TestClass : INotifyPropertyChanged
    {
        private string name;

        public TestClass(string NameValue)
        {
            this.Name = NameValue;
        }

        public String Name
        {
            get { return name; }
            set { this.name = value; NotifyPropertyChanged(); }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
        {
            if (this.PropertyChanged != null)
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

创建自定义DataGrid的ItemsSource - 无法正常工作

2 个答案: