WPF DataGrid自定义DataGridTemplateColumn.CellTemplate中ComboBox绑值问题

如有不理解的地方请留言。

1.主要解决问题：DataGrid滚动条拉动导致表格数据混乱、数据双向绑定、ComboBox数据源更改后默认显示空值（设置SelectedIndex为0无效

2.解决问题

2.1DataGrid滚动条拉动导致表格数据混乱

将DataGrid中EnableRowVirtualization属性值改为False，不进行动态数据显示。

EnableRowVirtualization="False"

2.2数据双向绑定

1.绑定数据源时设置ComboBox的两个关键属性

ItemsSource="{Binding ItemList,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"

2.数据源继承上INotifyPropertyChanged接口，实现接口成员方法，实现当数据源发生变化时通知控件数据源的更新

如：

public class ABC : INotifyPropertyChanged
    {
        public ABC()
        {
        }
        public string id;
        public string ID
        {
            get
            {
                return id;
            }
            set
            {
                id = value;
                OnPropertyChanged("ID");
            }
        }
        public string des;
        public string Des
        {
            get
            {
                return des;
            }
            set
            {
                des = value;
                OnPropertyChanged("Des");
            }
        }
        public string name;
        public string Name
        {
            get
            {
                return name;
            }
            set
            {
                name = value;
                OnPropertyChanged("Name");
            }
        }
        protected internal virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }

 

2.3ComboBox数据源更改后默认显示空值

ComboBox数据源更新后会执行一遍SelectionChanged事件，这时返回的SelectedIndex为-1，SelectedItem也是null；

解决方法：手动绑定SelectedIndex或SelectedItem值实现跟随数据源变化而变化（需要ComboBox数据源每项必须存在一个是否被选中的属性），我这边用的SelectedIndex。

自定义ComboxSelIndexConverter会在下面cs中贴出。

在window标签中加入：

xmlns:ValueConverter="clr-namespace:WpfTempleate.Converts"

在Window.Resources中加入：

<Window.Resources>
<ValueConverter:ComboxSelIndexConverter x:Key="ComboxSelIndexConverter"/>
</Window.Resources>

ComboBox中加入：

SelectedIndex="{Binding ItemList,Converter={StaticResource ComboxSelIndexConverter},Mode=OneWay}"

 对应的Class->ComboxSelIndexConverter.cs在下面贴出。

 

3.描述：

xaml->DataGrid

ItemsSource="{Binding People,ElementName=root}"
其中root是当前页面的name值，绑定上下文为当前页面对象，相当于DataContext="{Binding ElementName=root}"

People是DataGrid绑定的数据源(集合)

xaml->ComboBox

ItemsSource="{Binding ItemList,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
其中ItemList是ComboBox绑定的数据源（集合）
其中UpdateSourceTrigger=PropertyChanged是表示ComboBox发生变化时触发更新数据源

贴出代码

xaml：

<DataGrid  Width="500" Height="400" x:Name="dataGrid"
                        ScrollViewer.VerticalScrollBarVisibility="Auto"
                        ScrollViewer.HorizontalScrollBarVisibility="Auto"
                        VerticalScrollBarVisibility="Visible"
                        HorizontalScrollBarVisibility="Visible"
                        ItemsSource="{Binding People,ElementName=root}"
                        GridLinesVisibility="All"
                        BorderThickness="1,1,2,1"
                        CanUserDeleteRows="False"
                        CanUserAddRows="False"
                        AutoGenerateColumns="False"
                        EnableRowVirtualization="False">
                <DataGrid.Columns>
                    <DataGridTemplateColumn Header="Operation" IsReadOnly="True" x:Name="abc" >
                        <DataGridTemplateColumn.CellTemplate>
                            <DataTemplate >
                                <StackPanel Orientation="Horizontal">
　　　　　　　　　　　　　　　　　　　　　　<ComboBox x:Name="comList" 
                                                  IsReadOnly="True" 
                                                  IsEditable="True" 
                                                  Tag="{Binding ID}" 
                                                  HorizontalContentAlignment="Center" 
                                                  SelectionChanged="ComboBox_SelectionChanged" 
                                                  DisplayMemberPath="Name" 
                                                  SelectedValuePath="Value" 
                                                  SelectedIndex="{Binding ItemList,Converter={StaticResource ComboxSelIndexConverter},Mode=OneWay}" 
                                                  ItemsSource="{Binding ItemList,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
                                　　</ComboBox>
                         　　　　</StackPanel>
                　　　　　　　　</DataTemplate>
            　　　　　　　　</DataGridTemplateColumn.CellTemplate>
        　　　　　　　　</DataGridTemplateColumn>
    　　　　　　　　</DataGrid.Columns>
</DataGrid>                    

 

cs：

ComboxSelIndexConverter.cs

 

 

 

 

public class ComboxSelIndexConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            var abcs = (ObservableCollection<ABC>)value;
            if (abcs == null)
            {
                return -1;
            }
            else
            {
                if (abcs.Count == 0)
                {
                    return -1;
                }
                var abc = abcs.FirstOrDefault(f => f.Des == "1");
                if (abc != null)
                {
                    return abcs.IndexOf(abc);

                }
                return -1;
            }
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

 

Model数据源模型

 public class ABC : INotifyPropertyChanged
    {
        public ABC()
        {
        }
        public string id;
        public string ID
        {
            get
            {
                return id;
            }
            set
            {
                id = value;
                OnPropertyChanged("ID");
            }
        }
        public string des;
        public string Des
        {
            get
            {
                return des;
            }
            set
            {
                des = value;
                OnPropertyChanged("Des");
            }
        }
        public string name;
        public string Name
        {
            get
            {
                return name;
            }
            set
            {
                name = value;
                OnPropertyChanged("Name");
            }
        }
        protected internal virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }
    public class People : INotifyPropertyChanged
    {
        public People()
        {
            Genre = new Genre();
            ItemList = new ObservableCollection<ABC>(){
                new ABC(){ ID = "1",Name = "AAA",des="1"},
                new ABC(){ ID = "2",Name = "BBB",des="0"}
            };
        }
        public string ID { get; set; }
        public string Name2 { get; set; }
        public string Name { get; set; }
        public string Price { get; set; }
        public ObservableCollection<ABC> itemList;
        public ObservableCollection<ABC> ItemList
        {
            get
            {
                return itemList;
            }
            set
            {
                itemList = value;
                OnPropertyChanged("ItemList");
            }
        }
        public Genre Genre;

        protected internal virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }
    public class Genre
    {
        public string Name { get; set; }
    }

 

数据源绑定

public partial class MainWindow : Window, INotifyPropertyChanged
{
        public MainWindow()
        {
            InitializeComponent();
        }
        ObservableCollection<People> m_Peoples = new ObservableCollection<People>();

        public event PropertyChangedEventHandler PropertyChanged;
        protected internal virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }

        public ObservableCollection<People> People
        {
            get
            {
                return m_Peoples;
            }
            set
            {
                m_Peoples = value;
                OnPropertyChanged("People");
            }
        }
     　　public static ObservableCollection<People> GetPeopleAll()
        {
            ObservableCollection<People> People = new ObservableCollection<People>();
            for (int i = 0; i < 4; i++)
            {
                People.Add(new People() { ID = (i + 1).ToString(), Name = "李四" + (i + 1).ToString(), Name2 = "测试文本" + (i + 1).ToString(), Genre = new Genre() { Name = "张三" + (i + 1).ToString() }, Price = "100" + (i + 1).ToString() });

            }
            return People;
        }
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            
            People = GetPeopleAll();
            dataGrid.DataContext = People;
        }
}