DataGrid 数据绑定使用小结三(数据绑定)

上一节记录了数据绑定的自定义模板,可以在显示和编辑模板中添加任意控件实现业务需求,但出现一个问题

在编辑模板中进行编辑后却没有影响数据对象.这里要讲的是绑定的三种模式OneTime,OneWay,TwoWay

OneTime模式是在数据加载的时候显示数据,不影响数据对象也不被数据对象影响

OneWay模式受数据对象的变化而变化

TwoWay模式可以影响数据对象,也可以被数据对象影响

在上一节的代码中没有指定绑定的Mode(绑定模式),即系统默认为OneWay

但这里的绑定模式对数据对象有个要求,就是它要实现INotifyPropertyChange接口,(通知属性修发)

如果数据对象没有继承该接口,则数据对象改变后不会通知数据绑定控件属性修改事件

在继承了该接口后,上述三种模式才会显示其作用

数据对象类

/// <summary>
    /// DataGrid自定义列
    /// </summary>
    public class BookClass2 : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        private bool _isselect;
        private string _title;
        private double _price;
        private string _author;
        private DateTime _time;
        private string _sendmessage;
        private string _entity;

        /// <summary>
        /// 是否选择
        /// </summary>
        public bool IsSelect//DataGridCheckBoxColumn模板，模式不对其作用
        {
            get { return _isselect; }
            set { _isselect = value; }
        }
        /// <summary>
        /// 书名
        /// </summary>
        public string Title { get { return _title; } set { _title = value; NotifyProperty("Title"); } }//DataGridTextColumn模板，模式不对其作用
        /// <summary>
        /// 价格
        /// </summary>
        public double Price { get { return _price; } set { _price = value; NotifyProperty("Price"); } }//DataGridTemplateColumn模板，模式:OneWay，不改变数据对象，但受数据对象影响
        /// <summary>
        /// 作者
        /// </summary>
        public string Author { get { return _author; } set { _author = value; NotifyProperty("Author"); } }//DataGridTemplateColumn模板，编辑模板是ComboBox，模式:OneWay,改变数据对象用SelectionChanged事件
        /// <summary>
        /// 发布日期
        /// </summary>
        public DateTime Time { get { return _time; } set { _time = value; NotifyProperty("Time"); } }//DataGridTemplateColumn模板，显示模式:OneTime，只接受一次数据，不受数据对象改变影响
        /// <summary>
        /// 给该书留言
        /// </summary>
        public string SendMessage { get { return _sendmessage; } set { _sendmessage = value; NotifyProperty("SendMessage"); } }//DataGridTemplateColumn模板,模式：TwoWay，可以改变数据对象，也可以受数据对象影响
        /// <summary>
        /// 作者列表
        /// </summary>
        public List<Auth> AuthorList { get; set; }//ComboBox数据源
        /// <summary>
        /// 简介
        /// </summary>
        public string Entity { get { return _entity; } set { _entity = value; NotifyProperty("Entity"); } }//RowDetailsTemplate模板
        /// <summary>
        /// 实例化
        /// </summary>
        /// <param name="isselect">是否选择</param>
        /// <param name="title">书名</param>
        /// <param name="author">作者</param>
        /// <param name="entity">简介</param>
        /// <param name="price">价格</param>
        public BookClass2(bool isselect, string title, string author, string entity, double price)
        {
            IsSelect = isselect;
            Title = title;
            Author = author;
            Entity = entity;
            Time = DateTime.Now;
            AuthorList = Auth.List;
            Price = price;
        }


        #region INotifyPropertyChanged 成员
        private void NotifyProperty(string name)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(name));
        }

        #endregion
    }
    /// <summary>
    /// 作者类
    /// </summary>
    public class Auth
    {
        public string AuthName { get; set; }
        public static List<Auth> List = new List<Auth>() 
            { 
                new Auth { AuthName = "tnspop" },
                new Auth { AuthName = "tnsstar" }, 
                new Auth { AuthName = "tnssun" } 
            };
    }

DataGrid控件

<UserControl xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"  
             xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"  
             x:Class="DataGridTest.Control.DataGridBook2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="500">
    <StackPanel Orientation="Vertical">
        <data:DataGrid Name="gridSetColumns" AutoGenerateColumns="False">
            <data:DataGrid.Columns>
                <data:DataGridCheckBoxColumn Header="操作" Binding="{Binding IsSelect}"/>
                <data:DataGridTextColumn Header="书名" Binding="{Binding Title,Mode=OneTime}"/>
                <data:DataGridTemplateColumn Header="价格">
                    <data:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Price}"/>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellTemplate>
                    <data:DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <TextBox Text="{Binding Price,Mode=OneWay}"/>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellEditingTemplate>
                </data:DataGridTemplateColumn>
                <data:DataGridTemplateColumn Header="作者">
                    <data:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Author}"/>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellTemplate>
                    <data:DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <ComboBox ItemsSource="{Binding AuthorList}" SelectionChanged="ComboBox_SelectionChanged">
                                <ComboBox.ItemTemplate>
                                    <DataTemplate>
                                        <TextBlock Text="{Binding AuthName}"/>
                                    </DataTemplate>
                                </ComboBox.ItemTemplate>
                            </ComboBox>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellEditingTemplate>
                </data:DataGridTemplateColumn>
                <data:DataGridTemplateColumn Header="给作者留言">
                    <data:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding SendMessage}"/>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellTemplate>
                    <data:DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <TextBox Text="{Binding SendMessage,Mode=TwoWay}"/>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellEditingTemplate>
                </data:DataGridTemplateColumn>
                <data:DataGridTemplateColumn Header="发布日期">
                    <data:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Time,Mode=OneTime}"/>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellTemplate>
                    <data:DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <controls:DatePicker SelectedDate="{Binding Time,Mode=TwoWay}"></controls:DatePicker>
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellEditingTemplate>
                </data:DataGridTemplateColumn>
            </data:DataGrid.Columns>
            <data:DataGrid.RowDetailsTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding Entity}"/>
                </DataTemplate>
            </data:DataGrid.RowDetailsTemplate>
        </data:DataGrid>
        <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
            <Button Name="btnTest" Content="检测" Click="Button_Click" Width="60" Height="24" VerticalAlignment="Bottom" />
            <Button Name="btnUpdate" Content="修改数据对象" Click="btnUpdate_Click" Width="60" Height="24" VerticalAlignment="Bottom" />
        </StackPanel>
        <StackPanel Orientation="Vertical" Name="stackJC">
            <CheckBox IsChecked="{Binding IsSelect}" Name="chkisselct"/>
            <TextBox Text="{Binding Title}" Name="txttitle"/>
            <TextBox Text="{Binding Price}" Name="txtprice"/>
            <TextBox Text="{Binding Author}" Name="txtauthor"/>
            <TextBox Text="{Binding SendMessage}" Name="txtsendmessage"/>
            <TextBox Text="{Binding Time}" Name="txttime"/>
            <TextBox Text="{Binding Entity}" Name="txtentity"/>
        </StackPanel>
    </StackPanel>
</UserControl>

后台CS代码

public partial class DataGridBook2 : UserControl
    {
        List<BookClass2> list = new List<BookClass2>() 
            { 
                new BookClass2(true, "坏蛋是怎样炼成的", "tnspop","这本书讲了谢文东是如何从一个弱者变成一个强者的",12),
                new BookClass2(false, "咸郎平说", "tnsstar","这本书讲了一些常见的经济问题,分析的很透彻",43),
                new BookClass2(true, "帝国主义在中国", "tnssun","这本书讲了那些资本投资的金融学家在中国的一些见不得光的事情",26) 
            };
        BookClass2 bc;
        public DataGridBook2()
        {
            InitializeComponent();
            Databinding();
        }

        private void Databinding()
        {

            gridSetColumns.ItemsSource = list;
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            if (gridSetColumns.SelectedIndex == -1)
            { 
                MessageBox.Show("请选择一行"); 
                return; 
            }
            bc = list[gridSetColumns.SelectedIndex];
            stackJC.DataContext = bc;
        }

        /// <summary>
        /// 修改数据对象
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnUpdate_Click(object sender, RoutedEventArgs e)
        {
            if (bc == null) 
                return;
            bc.IsSelect = chkisselct.IsChecked.Value;
            bc.Author = txtauthor.Text;
            bc.Entity = txtentity.Text;
            bc.Price = double.Parse(txtprice.Text);
            bc.SendMessage = txtsendmessage.Text;
            bc.Time = DateTime.Parse(txttime.Text);
            bc.Title = txttitle.Text;
        }

        private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            (gridSetColumns.SelectedItem as BookClass2).Author = ((sender as ComboBox).SelectedItem as Auth).AuthName;
        }
    }

通过这个案例,我们可以看到

Mode=OneWay,则数据对象改变则可以影响DataGrid行,DataGrid行中修改数据不会影响数据对象

Mode=OneTime,则数据对象改变不会影响DataGrid行,DataGrid行中修改数据不会影响数据对象

Mode=TwoWay,则数据对象改变可以影响DataGrid行,DataGrid行中修改数据可以影响数据对象

在你双击行的时候如果有编辑模板的话,会从数据对象中重新获取数据.