【WPF】WPF DataGrid List数据源 双向绑定通知机制之ObservableCollection使用以及MultiBinding 的应用

以下代码实现了DataGrid的简单绑定List数据源

重点要提一下的是，绑定List数据源，但是不能直接用List。比如下面的代码，使用List<GridItem>只能实现数据修改的绑定，但是数据添加，删除都无法实现双向绑定。所以这里要改用ObservableCollection<GridItem>，其他代码都不用改。只要类型改下即可，WPF内部已经实现了添加，删除等的双向绑定功能。

接下去，就直接上代码了....

1、Model

public class GridModel
    {

        public GridModel()
        {
            GridData = new ObservableCollection<GridItem>();
        }
        public ObservableCollection<GridItem> GridData
        {
            get
            {
                return _griddata;
            }
            set
            {
                _griddata = value;
            }
        }

        private ObservableCollection<GridItem> _griddata;
    }

GridItem数据类

public class GridItem : INotifyPropertyChanged
    {
        public GridItem(string name, string sex, bool chk = false)
        {
            Name = name;
            Sex = sex;
            UserChecked = chk;
        }
        public string Name
        {
            get { return _name; }
            set {
                if (_name != value)
                {
                    _name = value;
                    OnPropertyChanged("Name");
                }
            }
        }
        public string Sex
        {
            get { return _sex; }
            set
            {
                if (_sex != value)
                {
                    _sex = value;
                    OnPropertyChanged("Sex");
                }
            }
        }
        public bool UserChecked
        {
            get { return _userchecked; }
            set
            {
                if (_userchecked != value)
                {
                    _userchecked = value;
                    OnPropertyChanged("UserChecked");
                }
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        private string _name;
        private string _sex;
        private bool _userchecked;
    }

2、ViewModel

public class GridViewModel
    {
        public GridViewModel()
        {
            GridSource = new GridModel();
            GridSource.GridData.Add(new GridItem("王路飞", "男"));
            GridSource.GridData.Add(new GridItem("娜美", "女", true));
            AddCommand = new DelegateCommand(Add, (obj) => true);
            DecCommand = new DelegateCommand(Dec, (obj) => true);
            ModifyCommand = new DelegateCommand(Modify, (obj) => true);
            ShowCommand = new DelegateCommand(Show, (obj) => true);
        }
        public GridModel GridSource
        { get; set; }

        public ICommand AddCommand
        { get; set; }
        public ICommand DecCommand
        { get; set; }
        public ICommand ModifyCommand
        { get; set; }
        public ICommand ShowCommand
        { get; set; }

        private void Add(object obj)
        {
            GridSource.GridData.Add(new GridItem("Luffy", "man",true));
        }
        private void Dec(object obj)
        {
            GridSource.GridData.RemoveAt(0);
        }
        private void Modify(object obj)
        {
            GridSource.GridData[0].Name = "路飞";
            GridSource.GridData[0].Sex = "女";
            GridSource.GridData[0].UserChecked = true;
        }
        private void Show(object obj)
        {
            MessageBox.Show(GridSource.GridData[0].Name + "," + GridSource.GridData[0].Sex + "," + GridSource.GridData[0].UserChecked);
        }
    }

3、XMAL

<Grid>
        <TextBox x:Name="textBox" HorizontalAlignment="Left" Height="23" Margin="27,25,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120">
        </TextBox>
        <Label x:Name="label" Content="Label" Margin="173,23,79,0" VerticalAlignment="Top"/>
        <Label x:Name="label1" Content="Label" Margin="233,23,19,0" VerticalAlignment="Top"/>
        <DataGrid x:Name="dataGrid" Margin="16,71,19,44" ItemsSource="{Binding GridSource.GridData}" AutoGenerateColumns="False">
            <DataGrid.Columns>
                <DataGridTemplateColumn Header="选中" Width="40">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <CheckBox IsChecked="{Binding UserChecked, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"></CheckBox>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
                <DataGridTextColumn Header="用户名" Width="80" Binding="{Binding Name, Mode=TwoWay}"/>
                <DataGridTextColumn Header="用户性别" Width="80" Binding="{Binding Sex, Mode=TwoWay}"/>
            </DataGrid.Columns>
        </DataGrid>
        <Button x:Name="button"  Content="添加" Command="{Binding AddCommand}" HorizontalAlignment="Left" Margin="16,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>
        <Button x:Name="button_Copy" Content="删除" Command="{Binding DecCommand}" HorizontalAlignment="Left" Margin="83,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>
        <Button x:Name="button_Copy1" Content="修改" Command="{Binding ModifyCommand}" HorizontalAlignment="Left" Margin="151,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>
        <Button x:Name="button_Copy2" Content="显示" Command="{Binding ShowCommand}" HorizontalAlignment="Left" Margin="220,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>

    </Grid>

4、后台代码

 this.DataContext = new ViewModel.GridViewModel();

功能补充：一个文本框绑定2个属性X+Y形式

1、XMAL修改，主要是绑定使用MultiBinding （红色是新增的）

<Window x:Class="AddMessage.BindingTest"
        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:AddMessage"
        xmlns:localmodel="clr-namespace:AddMessage.Model"
        mc:Ignorable="d"
        Title="BindingTest" Height="300" Width="300" WindowStartupLocation="CenterScreen">
    <Window.Resources>
        <localmodel:TextConverter x:Key="TxtConvert"></localmodel:TextConverter>
    </Window.Resources>
    <Grid>
        <TextBox x:Name="textBox" HorizontalAlignment="Left" Height="23" Margin="27,25,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120">
            <TextBox.Text>
                <MultiBinding Converter="{StaticResource TxtConvert}">
                    <Binding Path="Text" ElementName="lblleft"/>
                    <Binding Path="Text" ElementName="lblright"/>
                </MultiBinding>
            </TextBox.Text>
        </TextBox>
        <TextBox x:Name="lblleft" Text="1" Margin="173,23,79,0" Height="25" VerticalAlignment="Top"/>
        <TextBox x:Name="lblright" Text="2" Margin="233,23,19,0" Height="25" VerticalAlignment="Top"/>
        <DataGrid x:Name="dataGrid" Margin="16,71,19,44" ItemsSource="{Binding GridSource.GridData}" AutoGenerateColumns="False">
            <DataGrid.Columns>
                <DataGridTemplateColumn Header="选中" Width="40">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <CheckBox IsChecked="{Binding UserChecked, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"></CheckBox>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
                <DataGridTextColumn Header="用户名" Width="80" Binding="{Binding Name, Mode=TwoWay}"/>
                <DataGridTextColumn Header="用户性别" Width="80" Binding="{Binding Sex, Mode=TwoWay}"/>
            </DataGrid.Columns>
        </DataGrid>
        <Button x:Name="button"  Content="添加" Command="{Binding AddCommand}" HorizontalAlignment="Left" Margin="16,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>
        <Button x:Name="button_Copy" Content="删除" Command="{Binding DecCommand}" HorizontalAlignment="Left" Margin="83,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>
        <Button x:Name="button_Copy1" Content="修改" Command="{Binding ModifyCommand}" HorizontalAlignment="Left" Margin="151,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>
        <Button x:Name="button_Copy2" Content="显示" Command="{Binding ShowCommand}" HorizontalAlignment="Left" Margin="220,0,0,5" Width="53" Height="29" VerticalAlignment="Bottom"/>

    </Grid>
</Window>

 2、TextConverter 格式转换类，即处理，将2个文本合并成一个文本

public class TextConverter : IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            string val = "";
            foreach (var v in values)
            {
                if (val == "")
                    val = v.ToString();
                else
                    val += "+" + v;
            }
            return val;
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            string val = value.ToString();
            string[] vals = val.Split('+');
            return vals;
        }
    }