Revit 2021.1：DataGridRow选中时IsSelected属性不始终为True

问题描述 #

开发Revit 2021.1插件时，使用WPF DataGrid将行的IsSelected属性绑定到ElementParameterWrapper类的IsObjectSelected属性，但出现异常：即使DataGrid行已显示选中状态，IsObjectSelected有时仍为False。怀疑该问题与同时在两个DataGrid中选择对象有关。

涉及代码 #

XAML中的DataGrid及RowStyle

<DataGrid Grid.Row="1"
          Grid.Column="0"
          HorizontalAlignment="Left"
          Margin="10,0,10,10"
          ItemsSource="{Binding ListOfElementParameterWrappers, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
          RowStyle="{StaticResource RowToBeSelectedStyle}"
          AutoGenerateColumns="False"
          VerticalScrollBarVisibility="Auto"
          HorizontalScrollBarVisibility="Hidden"
          CanUserAddRows="False"
          CanUserResizeColumns="False"
          CanUserSortColumns="False"
          IsReadOnly="False"
          SelectionMode="Single"
          SelectionUnit="FullRow">
</DataGrid>

<Window.Resources>
    <Style x:Key="RowToBeSelectedStyle" TargetType="{x:Type DataGridRow}">
        <Setter Property="IsSelected" Value="{Binding IsObjectSelected}"/>
    </Style>
</Window.Resources>

ElementParameterWrapper类代码

public ElementParameterWrapper(Parameter parameter)
{
    Name = parameter.Definition.Name;
    Id = parameter.Id;
    if (parameter.IsShared)
    {
        GUID = parameter.GUID;
    }
}
public string Name { get; set; }
public ElementId Id { get; set; }
public Guid GUID { get; set; }
private bool isObjectSelected;
public bool IsObjectSelected
{
    get { return isObjectSelected; }
    set { isObjectSelected = value; }
}

解决方案 #

1. 明确绑定的双向模式与更新时机 #

默认绑定可能未启用双向同步，或更新触发时机滞后。修改RowStyle中的绑定配置：

<Style x:Key="RowToBeSelectedStyle" TargetType="{x:Type DataGridRow}">
    <Setter Property="IsSelected" Value="{Binding IsObjectSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Style>

2. 实现INotifyPropertyChanged接口 #

ElementParameterWrapper未实现属性变更通知，会导致UI与ViewModel状态同步中断。修改类代码：

public class ElementParameterWrapper : INotifyPropertyChanged
{
    public ElementParameterWrapper(Parameter parameter)
    {
        Name = parameter.Definition.Name;
        Id = parameter.Id;
        if (parameter.IsShared)
        {
            GUID = parameter.GUID;
        }
    }

    public string Name { get; set; }
    public ElementId Id { get; set; }
    public Guid GUID { get; set; }

    private bool isObjectSelected;
    public bool IsObjectSelected
    {
        get { return isObjectSelected; }
        set 
        { 
            if (isObjectSelected != value)
            {
                isObjectSelected = value;
                OnPropertyChanged(nameof(IsObjectSelected));
            }
        }
    }

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

3. 解决多DataGrid选择冲突 #

若两个DataGrid共享关联数据源，易出现选中状态互相覆盖：

• 确保两个DataGrid的SelectionMode和SelectionUnit配置一致；
• 避免两个DataGrid绑定的集合存在重复对象引用；
• 在ViewModel中为每个DataGrid单独维护选中项属性，替代依赖对象自身的IsObjectSelected：

  // ViewModel中新增两个选中项属性
  private ElementParameterWrapper _selectedItemGrid1;
  public ElementParameterWrapper SelectedItemGrid1
  {
      get => _selectedItemGrid1;
      set 
      {
          _selectedItemGrid1 = value;
          OnPropertyChanged(nameof(SelectedItemGrid1));
          // 可选：同步更新对象选中状态
          if (_selectedItemGrid1 != null)
              _selectedItemGrid1.IsObjectSelected = true;
      }
  }
  
  private ElementParameterWrapper _selectedItemGrid2;
  public ElementParameterWrapper SelectedItemGrid2
  {
      get => _selectedItemGrid2;
      set 
      {
          _selectedItemGrid2 = value;
          OnPropertyChanged(nameof(SelectedItemGrid2));
          if (_selectedItemGrid2 != null)
              _selectedItemGrid2.IsObjectSelected = true;
      }
  }
  

  对应XAML中给每个DataGrid绑定SelectedItem：

  <!-- 第一个DataGrid -->
  <DataGrid ... SelectedItem="{Binding SelectedItemGrid1, Mode=TwoWay}" />
  
  <!-- 第二个DataGrid -->
  <DataGrid ... SelectedItem="{Binding SelectedItemGrid2, Mode=TwoWay}" />
  

4. 处理Revit线程调度问题 #

Revit API要求操作必须在主线程执行，若绑定涉及Revit对象，需确保数据更新在正确线程：

// 使用Dispatcher确保在UI线程更新属性
Application.Current.Dispatcher.Invoke(() =>
{
    // 更新ViewModel属性或集合的操作
});

内容的提问来源于stack exchange，提问作者jazlik