如何将DataGridComboBoxColumn.ItemsSource绑定到DataGrid行的不同派生类Enum集合

1. 重构基类与派生类，实现枚举的抽象暴露 #

首先得给基类加两个抽象属性，让每个派生类自行返回对应的枚举选项和选中的命令，同时补全INotifyPropertyChanged的实现——你原来的基类只继承了接口但没实现通知方法，这会导致绑定不更新：

修正后的基类Base #

public abstract class Base : INotifyPropertyChanged
{
    public abstract event EventHandler<DataEventArgs> dataUpdate;
    public string? addr { get; set; }
    public string? name { get; set; }
    public string? port { get; set; }

    // 让派生类返回自己的枚举列表
    public abstract IEnumerable<object> CommandOptions { get; }
    // 保存当前选中的命令，派生类要转成自己的枚举类型
    public abstract object SelectedCommand { get; set; }

    // 实现属性变更通知
    public event PropertyChangedEventHandler? PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string? propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

调整Derived类 #

public class Derived : Base
{
    public override event EventHandler<DataEventArgs>? dataUpdate;

    public enum CMDS
    {
        CMD1 = 0x024F032E,
        CMD2 = 0x0253032A,
        CMD3 = 0x0252032B,
        CMD4 = 0x0250032D,
        CMD5 = 0x0270030D,
        CMD6 = 0x02570326
    }

    private CMDS _selectedCmd;
    // 实现基类的选中命令属性，只接受自己的枚举类型
    public override object SelectedCommand
    {
        get => _selectedCmd;
        set
        {
            if (value is CMDS cmd)
            {
                _selectedCmd = cmd;
                OnPropertyChanged();
            }
        }
    }

    // 返回当前类的所有枚举值
    public override IEnumerable<object> CommandOptions => Enum.GetValues(typeof(CMDS)).Cast<object>();
}

调整Derived2类 #

public class Derived2 : Base
{
    public override event EventHandler<DataEventArgs>? dataUpdate;

    public enum CMDS
    {
        CMD1 = 0x024F332E,
        CMD2 = 0x0224F32A,
        CMD3 = 0x0252032B
    }

    private CMDS _selectedCmd;
    public override object SelectedCommand
    {
        get => _selectedCmd;
        set
        {
            if (value is CMDS cmd)
            {
                _selectedCmd = cmd;
                OnPropertyChanged();
            }
        }
    }

    public override IEnumerable<object> CommandOptions => Enum.GetValues(typeof(CMDS)).Cast<object>();
}

2. 用DataGridTemplateColumn替换DataGridComboBoxColumn #

DataGridComboBoxColumn的ItemsSource只能绑定到列级上下文，没法拿到当前行的派生类实例，所以必须换成DataGridTemplateColumn，里面嵌套ComboBox，这样就能直接绑定到每行的数据：

修改后的XAML #

<DataGrid ItemsSource="{Binding Collection}" AutoGenerateColumns="False" CanUserAddRows="False">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Name" Binding="{Binding name}"/>
        <DataGridTextColumn Header="IP Address" Binding="{Binding addr}"/>
        <DataGridTextColumn Header="Port" Binding="{Binding port}"/>
        <!-- 动态加载对应派生类枚举的ComboBox列 -->
        <DataGridTemplateColumn Header="Command">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <ComboBox ItemsSource="{Binding CommandOptions}"
                              SelectedItem="{Binding SelectedCommand, Mode=TwoWay}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
            <DataGridTemplateColumn.CellEditingTemplate>
                <DataTemplate>
                    <ComboBox ItemsSource="{Binding CommandOptions}"
                              SelectedItem="{Binding SelectedCommand, Mode=TwoWay}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellEditingTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

为什么原来的方法行不通？ #

• 你之前在基类加CmdsList的问题：基类不知道具体派生类的枚举，没法动态返回对应的值，而且绑定到Window的DataContext只能拿到基类的属性，区分不了每行的派生类型。
• DataGridComboBoxColumn的局限性：它的ItemsSource是列共享的，没法针对每行加载不同的选项，必须用模板列才能实现行级的动态绑定。

内容的提问来源于stack exchange，提问作者gwiz_kid